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Stretch the glide

In the event of an engine failure, airplanes have a distinct advantage of being able to glide farther than helicopters, hopefully far enough for a safe forced landing.  While helicopters can’t glide as far, they do have the great benefit of being able to land with little to no groundspeed, greatly improving the survivability of those on board. The best of both worlds would be to be able to glide efficiently and then land without any groundspeed. While a helicopter is able touch down with little to no groundspeed, a glide angle of about 18 degrees won’t garner much range. However, there is a technique, not included in the FAA Rotorcraft Flying Handbook, that can be used to extend the range and in some cases help reach a more desirable landing area.

During an autorotation there are many things a pilot can do when too high; turns, slips/skids, or airspeed adjustments. However, when faced with the situation of being too low, there is only one thing a pilot can do.  Extend the autorotation glide.

There are four factors in an autorotation that affect the descent rate: density altitude, gross weight, rotor RPM, and forward airspeed.  While we can’t control density altitude or gross weight (unless jettisoning an external load), we can control rotor RPM and forward airspeed. In a forward flight autorotation one can significantly increase the range by increasing airspeed and lowering rotor RPM, while still complying with the Rotorcraft Flight Manual limitations for that particular helicopter.

Let’s take airspeed first, using the Agusta Westland 139 as an example, referring to the RFM limitations and emergency procedures sections. The AW139 has a minimum autorotational airspeed of 40 knots, a minimum rate of descent autorotational airspeed of 80 knots, and a best range autorotational airspeed of 100 knots. Some helicopters may not have a best range airspeed published, but instead a maximum autorotational airspeed. In any case, one would use the autorotational maximum airspeed or best range airspeed to extend the power-off glide. Note, the minimum rate of descent airspeed also corresponds with the best rate of climb airspeed (Vy), as this is the airspeed where the coefficient of the lift to drag ratio is highest. The farther one deviates from Vy the greater the descent rate. Know that exceeding the maximum or best range autorotation speed can cause rotor RPM decay and put undue stress on the rotor blades, and we certainly don’t want to decay rotor RPM because we want to use it for lift to extend the range in an autorotation.

We have increased speed to the maximum allowable, but are now faced with an increased descent rate as the helicopter is now faster than Vy. However, this can be compensated for by increasing collective and reducing rotor RPM to minimum allowable, which decreases the descent rate.  The AW139 has a power-off rotor RPM limitation of 95-110 percent, not counting transient limitations.  In order to maximize the autorotational range of the AW139, fly at 100 knots and 95 percent RPM. At some point with ample altitude remaining, the pilot would reduce the airspeed to the recommended 80 knots and increase the RPM to the recommended 110 percent. This provides as much energy as possible to the rotor system for landing. Aircraft vary as to how quickly they can recover rotor RPM, and while a low inertia rotor system will recover quicker it will also have less energy during pitch pull before touchdown.

There is really just one reason to fly an autorotation at the maximum airspeed and lower range of rotor RPM, and that is to increase the range of the helicopter. As we increase collective, pitch is increased and the L/D (lift drag ratio) of the rotor system becomes more efficient and more lift is produced.

Next training session, try a couple of extended range autorotations and compare them to the standard ones. Results vary with the type of helicopter, but the difference is very significant in the aircraft I have flown.  ou will likely find the rate of descent at high speed/low RPM to be even less than the rate at Vy/normal RPM. A lower descent rate coupled with a higher airspeed greatly enhances the range, which could make all the difference someday.

Markus Lavenson is currently flying for Era Helicopters as a captain in the Sikorsky S92 and Leonardo Helicopters AW139 in Alaska and the Gulf of Mexico in oil and gas support missions. His varied career began shortly after graduating from the University of California at Davis, and has included everything from flight instruction and powerline patrol to HEMS and external load operations. His more than 10,000 hours of flight time comes from more than a dozen different types of helicopters and airplanes. Holding an ATP helicopter and commercial multi-engine fixed-wing, he also is a flight instructor fixed-wing and instrument flight instructor helicopters. Lavenson enjoys the intricate work of helicopter instrument flying, whether it’s to an airport on Alaska’s North Slope or one he creates to an oil rig hundreds of miles offshore.

Using a big fan

When I bought my helicopter back in 2005, I was living in the Phoenix area. Arizona is nice — in the spring, summer, and autumn. But in the summer it’s brutally hot and no amount of air conditioning (which I didn’t have in my helicopter anyway) can make it bearable when you’ve parked on the tarmac with your cockpit in the sun waiting for a client. That’s if you can get any flying work at all.

After the summer of 2005, I’d had enough of it. Since another season at the Grand Canyon was out of the question, I began looking for other work for the summer of 2006. I was hoping that a tour operator in a cooler place would need an extra ship for their busy season.

What I got instead was a call from a guy named Erik based in the Seattle area. He told me that he was doing cherry drying work every summer and was always looking for pilots to help.

Cherry drying, explained

The explanation is simple: During the last three to four weeks before harvest, cherries are susceptible to damage from rain. If water from a rainfall is allowed to sit on the fruit, it can be absorbed through the skin, causing the cherries to expand and split. Moisture on the cherries can also cause mold and mildew. Any of these things can make the cherry unsalable. If 50 percent or more of an orchard’s crop is damaged, the orchardist won’t even bother picking and the whole crop will be lost.

To protect the cherries, orchardists hire helicopter pilots to stand by in the area with their helicopters. When it rains, they call the pilots out to fly, low and slow, over the treetops. The down wash from the rotor blades blows down into the tree’s branches, causing them to wave violently and shake the water off the fruit. Many orchardists refer to this as “cherry blowing,” which is a far more accurate description of what’s being done.

About cherry drying contracts

Cherry drying is contract work. Although it’s done in California, Oregon, and Washington, most of the cherry orchards and work is in Washington. The season is relatively short, starting as early as April in California and ending as late as August in some areas of Washington. Pilots are contracted either directly by orchardists or by service providers who are contracted by the orchardists who then subcontract out to pilots. Contracts are usually no shorter than 3 weeks; most include the possibility of “extensions” that may add days or weeks to that.

During the course of the contract, the pilot is required to base himself and his aircraft in the service area and stay there. That means getting lodging nearby and a means of transportation to get to and from the helicopter. Pilots are on call any time it’s light enough to fly — unlike frost control work, which I’ll cover in my next blog post, no flying is done in the dark. In Washington in June and July, the days are very long. Following the “eight hours from bottle to throttle” rule, it’s unlikely that you’ll go out drinking with your fellow pilots in the evening; you could get called before dawn the next day.

Pilots are expected to be airborne within minutes of getting the call. For this reason, they should be keeping an eye on the weather. If rain is in the area, the pilot should have the helicopter all fueled, preflighted, and ready to go. The pilot needs to get out to the orchard needing service and get right to work flying over the trees. To do that, the pilot needs to know exactly where each of his orchards are and be familiar with their boundaries and obstacles before the first call comes.

Contract terms have two parts: standby and fly time. Standby is the amount received for having the helicopter based at or near the orchards under contract. This daily rate should cover the cost of lodging and transportation for the pilot, as well as repositioning the helicopter to and from the contract base from home. It should also provide some sort of compensation for having the helicopter offline from other work. Obviously, the longer the contract, the more standby money is available to cover costs and possibly build a profit. Fly time is straightforward: it’s hourly pay for when the helicopter is actually flying over an orchard.

The work

When I say we fly “low and slow,” I need to make it clear just how low and slow we fly. My rule of thumb is 5-10 feet off the treetops and 5-10 miles per hour (or knots). It’s not unusual for me to come back from a flight with cherry tree leaves stuck in my skids where the ground handling wheels connect to my R44. Of course, with certain types of cherries — Rainiers, for example — a pilot needs to fly higher to prevent the more delicate fruit from getting damaged. And if a pilot is flying something bigger — say a Huey or S55, both of which are used in my area of Washington — he’ll need to fly higher so he doesn’t damage the trees.

A cockpit shot during a typical cherry drying flight. Note that the sun is out and my door is off.

A cockpit shot during a typical cherry drying flight. Note that the sun is out and my door is off.

Here's an example of a track for a quick dry of a large orchard. Areas I didn't cover were already picked.

Here’s an example of a track for a quick dry of a large orchard. Areas I didn’t cover were already picked.

How a pilot flies the rows of trees is something that varies depending on how dense the trees are. That varies with height, pruning, variety, age, distance apart, etc. Flying every other row is usually enough for most orchards. It’s even overkill for others. It really depends.  Depending on the orchard layout and obstacles, an R44 can dry 30 to 50 acres in an hour. The goal is to get the fruit as dry as possible as quickly as possible.

Because yes: the click is ticking. I’ve gotten all kinds of numbers from a variety of sources, but most of them agree that the cherries need to be dried within two to three hours of getting wet. That time is shortened if it gets warm and sunny out, which it usually does.

Although it’s usually done raining when a dry call comes, some orchardists will call to begin drying when it’s still raining. Some of them do this to make sure the pilot gets to their orchards first — with several (or even many) orchards assigned to a pilot, there’s a real competition between orchardists to get their pilot before another orchardist does. Sometimes a pilot will have to fly through a storm to get to an orchard on the other side of it where the rain has already stopped. (I’ve flown through more thunderstorms than I care to remember just getting from one orchard to another.) Sometimes a pilot will be halfway through an orchard when another rainstorm moves in; what he does then depends on orders from the person who hired him.

A fly call can come as early as 4 a.m. if it rained overnight. That doesn’t mean a pilot has to launch then, but it does mean he has to get ready to launch. I’ve spent more than a few predawn minutes sitting in my cockpit, waiting to see the horizon so I could crank the engine and prepare to depart. The earliest I’ve ever been over an orchard was 4:30 a.m.; although it was still quite dark, I was very familiar with the orchard and felt confident about flying it with the aid of my landing lights. Other times, I’ve flown past sunset. My rule is: if I can see, I’ll fly. When I can’t see, it’s time to go back to base.

When the sun comes out during a flight — which it almost always does — it can get unbelievably hot in the cockpit. It’s a miserable feeling to have stinging sweat dripping off your forehead and into your eyes and not be able to use either hand to wipe the sweat away. For this reason, I always fly with one door off. No matter how cold and cloudy and possibly even still rainy it is when I launch, I’ll be very glad I took that door off when the sun comes out.

Skilled pilots needed

The flying is intense. Both hands and feet are on the controls making tiny adjustments to all flight controls for hours at a time. Excellent hovering skills and familiarity with the aircraft are vital. A tailwind will have a pilot working the pedals just to keep flying straight. And if the orchard is on a hill, there’s plenty of sideways flying to keep the tail rotor out of the trees when flying downhill in order to remain close enough to the trees to stay effective.

Obstacles can include power lines, sometimes with poles right in the orchard.

Obstacles can include power lines, sometimes with poles right in the orchard.

With cherry trees 10 to 30 feet tall, all flights are well within the Deadman’s Curve. No doubt about it: if there’s  an engine failure, the helicopter is going down into the trees. The pilot has to hope the trees break the fall and keep the main rotor blades from entering the cockpit. (That’s one of the reasons I fly over aisles between trees and not the trees themselves.) Pilots who are squeamish about things like this need not apply.

The flying can be dangerous, especially when pilots lack the required skills or become too complacent to stay focused. We normally have at least one bad crash a year. Want to read up on some of the accidents? Here are some links to get you started; the two Sikorsky crashes happened on the same day:

(*Apparently, some operators are conducting “training” flights while on actual cherry drying missions. I think this is a huge mistake.)

Finally, drying cherries is not a time-building job. My first season, back in 2008, was 7 weeks long. During that time, I flew about 5 hours. The following year I had 11 weeks of contract work and also flew only 5 hours. Since then, it’s been a bit rainier each season, but I still average less than 3 hours of flight time per week. Last year was especially disappointing, with two of my pilots not getting any flight time at all.

Getting Started

If you like what you’ve read and think you want to try a season of cherry drying, the best way to get started is to keep your ears open for service providers looking for helicopters. Unfortunately, they’re not looking for pilots unless those pilots can bring a helicopter. So don’t bother calling around unless you also have a helicopter lined up to bring with you.

R44 helicopters are the ones most commonly used for cherry drying. Why? Because they’re cheap to operate and they move a lot of air. (I’ll argue that they move as much air as a JetRanger.) Generally anything relatively large with a two-bladed rotor system will do the job well. R22s are too small to cover a large orchard quickly, although they’re handy for small orchards with lots of obstacles and tight space. Ditto for Schweizers, although I think they push more air than R22s. The owners of large orchards prefer larger helicopters because they can blow more cherries faster.

Most service providers hire pilots/helicopters for a minimum contract term of three weeks with an option to extend by days or weeks as needed. In most cases, need is determined by the acres of unpicked cherries and the upcoming weather forecast. Each pilot gets a handful of orchard photos or Google satellite view images with coordinates and is expected to learn them. There usually isn’t any overlap; a pilot is responsible for just his orchards. That’s a two-edged sword: if it rains in a pilot’s area, he can do a lot of flying. If it rains elsewhere, he won’t do any flying at all.

I work my contracts with other pilots work a little differently. Last season, I hired four guys to work with me with contracts of at least four weeks each. We work together in two teams serving two different geographical areas. Each team knows where all the orchards are in their area. When the calls start coming, I start dispatching us to orchards. My goal is to to provide my clients with the fastest service possible, making the most of my assets (the pilots and their helicopters). If only one big orchard gets rained on, it’s not usual for me to put two or even three helicopters on it. But if rain is widespread, so are we — covering individual orchards as quickly as we can. Although I try to dispatch based on area, when there’s a lot of rain, all of the helicopters are in the air, even if that means a pilot has to fly across town to get to the next orchard that needs attention.

Of course, of the two areas we serve, one didn’t get any rain at all. Those two pilots didn’t fly; it simply didn’t make sense to fly them to the other area where they might have gotten an hour or two of flight time. But if a pilot can’t make it work financially based on the standby portion of the contract, he probably shouldn’t bother taking the contract at all. You have to go into a contract assuming it won’t rain — and be very happy when it does.

When the weather is clear and sunny and there’s no rain in the forecast, pilots are pretty much free to do whatever they like — as long as they watch the weather and can get back to base in a hurry if things change. Hiking, bicycling, swimming, paddling — there’s plenty to do in the area to keep busy. I used to think of it as a paid vacation with a handful of days when I needed to work. While it isn’t for every pilot, I certainly enjoy it.

I can hear the radios and smell the smoke

Meet Joe Kline.

I first met Kline 15 years ago, and recently had the pleasure of seeing him again. His art brings to life and honors those who lived and died flying the helicopters of the Vietnam War.

Joe is an acclaimed artist painting military aircraft and the people who crewed them. His primary focus is on Army helicopters of Vietnam where he served in the 101st Airborne. His paintings grace the rooms of several museums, including the Smithsonian Air and Space Museum.

Kline

Joe’s father was a bombardier on a B-25 Mitchell during World War II, so it was only natural he grew up with a passion for military aviation. During the Vietnam War Joe joined the Army and tested high for a mechanical aptitude. He was assigned to helicopter maintenance unit in Qui Nhon, but he wanted to fly.  Joe soon got his wish and was transferred to Camp Eagle in Hue. He was now in the esteemed 101st Airborne, as a crew chief and door gunner of a Bell UH1 Huey.

While in the 101st Joe saw a lot of action and was involved in the Lam Son 719 offensive in 1971, where 10 percent of the total helicopter losses of the war occurred. While he managed to get some photographs, there wasn’t a lot of time nor was it the place for his artistic talents. The 101st did not encourage nose art on the aircraft, but Joe did manage to design and paint a few unit emblems.

Joe Kline

Joe Kline

Joe now honors those who served by creating historically accurate paintings. He tells me he must be completely accurate, if a rivet is out of place or a control surface in the incorrect position for a particular regime of flight, he will hear about it from someone.

Joe gets the most satisfaction when his art touches people and helps them reconnect. He once painted a Huey, hovering full of ground troops taking an RPG (rocket propelled grenade) while a gunship provided cover from above. Like all his paintings, this was a true event that took place in 1967. It appeared on the cover of Vietnam magazine and was recognized by one of the survivors. The gunship pilot saw the picture and began reaching out to the others.  He eventually reunited with the copilot of the downed Huey, and in turn contacted other survivors of that tragic day.

In addition to reuniting people, Joe gets satisfaction when a veteran stares at his work and quietly says, “I can hear the radios and smell the smoke.”

You see some of Joe’s work at www.joeklineart.com

Markus Lavenson is currently flying for Era Helicopters as a captain in the Sikorsky S92 and Leonardo Helicopters AW139 in Alaska and the Gulf of Mexico in oil and gas support missions. His varied career began shortly after graduating from the University of California at Davis, and has included everything from flight instruction and powerline patrol to HEMS and external load operations. His more than 10,000 hours of flight time comes from more than a dozen different types of helicopters and airplanes. Holding an ATP helicopter and commercial multi-engine fixed-wing, he also is a flight instructor fixed-wing and instrument flight instructor helicopters. Lavenson enjoys the intricate work of helicopter instrument flying, whether it’s to an airport on Alaska’s North Slope or one he creates to an oil rig hundreds of miles offshore.

Runways are for beauty queens

“Hey, is that your helicopter?”

Naturally, he had to be talking to me, being the only one in the room remotely looking like a helicopter pilot. I was wearing a nomex flight suit with black boots, surrounded by corporate pilots decked out in suits and ties. I stood out as much as my Bell 222 out on the ramp with a covey of corporate jets. We both looked out of place at the San Francisco International Airport FBO.

After I said it was, he asked, “How fast does it go?”

I thought jeez here we go again, what is it with jet guys? It’s like an Indy driver asking how fast a four-wheel drive truck can go.

“Oh, she will cruise about 130 knots,” I said. I heard a few snickers around the room from the younger copilots. The older captains seemed bored reading their newspapers.

Okay my turn I thought.  “Which airplane are you flying?” I innocently asked, as he proudly pointed to one of the sleek jets.

“Nice. How slow can it fly?”

“What do you mean?” he asked, somewhat flustered.

“How slow can it fly?” I repeated.

He looked at me a little perplexed and said, “Well, in a landing configuration, we can do about 105 knots.”

“You’re kidding right?  Is that as slow as you can possibly get that thing?” I said with feigned incredulity. I noticed the newspapers being lowered and the captains didn’t look bored anymore.

He said “No, that’s about as slow as they can fly,” looking around the room for a little help.

I said, while nodding my head sympathetically, “That is a severe limitation, but if you stick to runways you should be okay.”

“The helicopter is ultimate off-road vehicle,” I said. “I can put it on a mountaintop, highway, beach, or rooftop helipad anytime of day or night. I can pick up an accident victim having the worst day of her life and fly her to a trauma center in a matter of minutes. That helicopter is a single-pilot IFR capable aircraft that flies about 400 patients a year, and it rarely uses a runway. It isn’t the fast, but the slow that matters in my world.”

We all had a good laugh, and one of the captains said, “Well, nobody in this room is ever going to ask another helicopter pilot how fast their helicopter can fly.”

As I left the room I looked through the window at all the beautiful, though severely limited corporate jets and said, “Runways are for beauty queens.”

Out on the ramp, thinking about the comparison of airplanes and helicopters, I thought back to the 1980s when I had introduced a friend to helicopters for the first time.

We had met flying Beech 18s and a Cessna 182 for a skydiving operation on weekends. He had never been in a helicopter, so early one evening after flying a powerline patrol I took him up for a short ride. I removed the doors, my preferred way of flying in those days, and we enjoyed the cool Carolina air.

After flying around for a bit we returned to the airport and I figured I would demonstrate some of the unique abilities of the helicopter. On final approach to a runway, I bled off airspeed while maintaining altitude at 400 feet. As the airspeed indicator crept lower and lower, my friend sat straighter and straighter in his seat.

I said, “This must feel a little strange to you?”

“Yep,” was all he could muster.

Eventually, he was gripping the sides of the seats in true white-knuckle fashion as the airspeed indicator reached zero. We remained motionless at a high hover, with the runway right in front of us.

“Pretty cool, huh?” I said, as he stared at the airspeed indicator.

He said nothing.

“Isn’t this awesome?” I tried again.

“Everything I fly would be falling out of the sky,”  he replied tersely.

After a minute, I noticed the blood was returning to his fingers. He was relaxing and getting used to the idea that airspeed was totally unnecessary for powered flight. I then lowered the collective slightly, dropped the nose and swooped in a shallow approach profile for the runway doing a quick stop at a taxiway intersection. I then continued down the runway at a hover taxi speed with a couple of 360-degree pedal turns thrown in for practice.

Minutes later, as we air-taxied behind one of the Beech 18s and gently set down on the grass, he said, “Okay, tell me about how long and how much to get my helicopter pilot license.” He had gone from white knuckles to wanting to fly helicopters, and in just a few minutes.

I believe deep down his heart was saying, “Yeah, runways are for beauty queens.”

This is all meant in good fun, and mainly, in awe of our machines. Have a “runways are for beauty queens” story?  Share it below in the comments section.

Markus Lavenson is currently flying for Era Helicopters as a captain in the Sikorsky S92 and Leonardo Helicopters AW139 in Alaska and the Gulf of Mexico in oil and gas support missions. His varied career began shortly after graduating from the University of California at Davis, and has included everything from flight instruction and powerline patrol to HEMS and external load operations. His more than 10,000 hours of flight time comes from more than a dozen different types of helicopters and airplanes. Holding an ATP helicopter and commercial multi-engine fixed-wing, he also is a flight instructor fixed-wing and instrument flight instructor helicopters. Lavenson enjoys the intricate work of helicopter instrument flying, whether it’s to an airport on Alaska’s North Slope or one he creates to an oil rig hundreds of miles offshore.

Slinging IFR

Flying helicopters IFR with a sling load presents unique challenges, requiring specific skills of the pilot.  One must obviously be able to control the helicopter without any outside visual references. Less obvious, one must also be able to correctly interpret the instruments, which reflect both the behavior of the load and the orientation of the helicopter. A Class B external load (sling load) is one that is free of the earth’s surface and is attached to the helicopter by a synthetic or wire line. The pilot is “flying” both the helicopter and the load, which at times can seem to have a mind of its own.

Today slinging IFR is not a common practice, though there was a time on the North Slope of Alaska where it was employed regularly. I thought it might be interesting to look at this operation in some detail.

 

An AW139 lifts off for an external load training flight out of Deadhorse Alaska.  Photo by Dan Adams

An AW139 lifts off for an external load training flight out of Deadhorse Alaska. Photo by Dan Adams

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Controlling the sling load

Normally one can see the external load, and make the necessary corrections. Lateral swinging is more common than a fore-aft motion or a circular motion, so we will focus on that. A quick lateral cyclic input towards the load, just as it reaches its apex, moves the aircraft over the load neutralizing its motion. You are essentially moving the aircraft over the load after it has swung out to the side. This dampens the movement of the load and stabilizes it. However, when flying IFR the instruments must be used to indicate the loads’ position and movement. The best way to learn how the instruments reflect the movements of the load is during VFR flight, when the load and gauges can be seen together.

Flying IFR with a sling it is important not to make corrections reflecting the gauges as one normally would, but instead understand exactly what the load is doing beneath you. The attitude indicator reflects rhythmic changes in bank angle from the load tugging the helicopter laterally side to side, as does the ball in the inclinometer. The inclinometer is used to indicate when and how much lateral cyclic input is necessary for a correction, though there is a natural lag. The load will reach its apex prior to the inclinometer, and the pilot must compensate for this natural lag. When the ball starts to swing out of center to the right and is about half way from its apex, the load is almost at its apex to the left, the pilot then uses left lateral cyclic as a correction. The rhythmic oscillations in the attitude indicator and inclinometer reflect the movements of the load, and the average of these movements are the actual orientation of the aircraft.  The pilot learns to mentally average these oscillations in order to control the pitch, roll, and yaw of the aircraft itself.

“An ounce of prevention is worth a pound of cure”, so one learns to make flight control inputs very smoothly so as to not aggravate the load. Turns are initiated slowly, and half standard rate turns are sometimes prudent.

Determining cruise airspeed

Another consideration is determining the target airspeed at which to fly.  This must be greater than Vmini (minimum IFR speed) and less than the loads effective Vne. While the aircraft will have an external load airspeed limitation, this may not be possible if the load is unstable at a lower speed. Many loads cannot be flown at the external load Vne, and the effective Vne must be determined. As the pilot slowly accelerates during takeoff, the load is carefully watched prior to IMC to determine what airspeed above Vmini the load can be flown at. Once that airspeed is determined, it is maintained for the entire flight.

Should the load show signs of instability below Vmini or only slightly above so as to not provide a safe and adequate airspeed window, the takeoff is aborted while still VMC.

One should be sure of a load’s stability and capability at a safe airspeed prior to IMC, and one should only fly known loads in IFR or at night. A known load is one that is similar to one previously flown during the day. The load characteristics are predictable and stable.

Autopilots and external load operations

Autopilots and external loads don’t usually mix, and many Rotorcraft Flight Manuals prohibit autopilot coupling during external load operations. The autopilot can be too abrupt in pitch attitude and roll, particularly when initiating and terminating turns. A pilot can make changes with a more gentle touch; such as slowly entering a half-standard rate turn when necessary. The autopilot can be used for stability augmentation; it just shouldn’t be coupled to the flight director directly controlling the aircraft.

Horizontal and vertical situational awareness

Class B sling loads can be jettisoned, either intentionally or unintentionally. The hook release is typically electric and controlled by the pilot. Under normal operation the load is released once it has been placed gently on the ground; however, in the case of an emergency the pilot may opt to release it in flight. Due to the possibility of the load being released in flight, persons or property are never overflown. This requires horizontal situational awareness; easy enough VFR, but IFR is another matter. Fortunately, the North Slope of Alaska provides assurance due to its desolate nature.

Vertical situational awareness must also be considered, not just for the helicopter but also for the load hanging underneath. With the typical 25 to 50’ line, the altitude of the load isn’t a factor in cruise flight; however, during the instrument approach it must be considered.

The Instrument Approach

As much fun controlling the helicopter and load may be in IFR conditions, eventually we do need to land. For that we need to fly an instrument approach. Let’s stick with the North Slope of Alaska, using the Deadhorse (PASC) ILS 05 as an example, using a little simple math.

A load 5 feet high hanging on a 50 foot line would require a 55 foot adjustment factor to the decision altitude. For the Deadhorse ILS, this means increasing the decision altitude of 267 feet to 322 feet, and ALS conditional altitude of 167 feet to 222 feet. It would also be prudent to include this 55 foot altitude adjustment into your preflight IFR planning.

Final Thoughts

While flying slings IFR is no longer common, the training for IFR slings still occurs. Having the skill and confidence to be able to fly a sling IFR is vital should unforecasted adverse weather be encountered, not unheard of on the Alaskan North Slope where the weather can change quickly. Airports and options are few and far between north of the Brooks Range of Alaska. These skills also translate well and are employed for night sling operations, which are still done on a regular basis.

Markus Lavenson is currently flying for Era Helicopters as a captain in the Sikorsky S92 and Leonardo Helicopters AW139 in Alaska and the Gulf of Mexico in oil and gas support missions. His varied career began shortly after graduating from the University of California at Davis, and has included everything from flight instruction and powerline patrol to HEMS and external load operations. His more than 10,000 hours of flight time comes from more than a dozen different types of helicopters and airplanes. Holding an ATP helicopter and commercial multi-engine fixed-wing, he also is a flight instructor fixed-wing and instrument flight instructor helicopters. Lavenson enjoys the intricate work of helicopter instrument flying, whether it’s to an airport on Alaska’s North Slope or one he creates to an oil rig hundreds of miles offshore.

OSAPs, HEDAs, and ARAs oh my!

Imagine being able to create an instrument approach while en-route, and then fly the approach down a minimum of 200 feet and 3/4sm. Not as crazy as it sounds. Here’s why:

IFR helicopters do this regularly, supporting the offshore petroleum industry in the Gulf of Mexico, flying as far as 200 miles offshore to land on ships, drill rigs, spars, and platforms.  All in accordance with Advisory Circular 90-80B: Approval of Offshore Standard Approach Procedures (OSAP), Airborne Radar Approaches (ARA), and Helicopter En Route Descent Areas (HEDA).  The title is certainly a mouthful, and the 58-page document can also be a little daunting. It helps to look at one in action, in this case the popular Copter Delta 30 OSAP, pronounced as “Oh-Sap.”

Before first light, prior to start-up for an IFR flight offshore, which will incorporate an OSAP approach to the destination rig.  Photo by Alex Geacintov

Before first light, prior to start-up for an IFR flight offshore, which will incorporate an OSAP approach to the destination rig. Photo by Alex Geacintov

The Copter Delta 30 OSAP is one of five charted templates in AC90-80B that a pilot can adapt to almost any location offshore. It requires specific two pilot crew training, GPS, ground mapping capable radar, and radio/radar altimeter. It is a SIAP (special instrument approach procedure), and therefore also requires FAA authorization.

While en-route, destination weather is rechecked via radio or satellite phone. If the destination doesn’t have approved weather reporting, normally required under part 135, some operators have an FAA authorization to use remote reporting stations. Operations Specifications are regulatory and issued by the FAA, with some being more restrictive and some less restrictive than the associated FAR. Think of them as an extension of the FARs for specific operators. In this case the Op Spec is less restrictive, which is a good thing because although there are some AWOSs  offshore, there never seem to be enough.

The OSAP Delta 30

The OSAP Delta 30

Wind condition at the destination is used to determine the approach course, which must be into the wind. A DWFAP (down wind final approach point) is typically created 7nm downwind from the destination, on the final approach course. The DWFAP can be created anywhere on the final approach course, as long as it is between 5 and 10nm from the destination. Depending on the en-route direction, a course reversal may be necessary in order to establish the helicopter inbound on course at the DWFAP. All this is planned and created while en-route, and then programmed into the Flight Management System or GPS. Radar in ground-mapping mode is used to determine there are no obstacles within .5nm of the final approach course. The final approach course can be adjusted for obstacles, just as long as it is within 10 degrees of the wind.

When 40nm or less from the destination, a cruise clearance is requested from ATC. This allows an immediate descent to MEA, an eventual descent to 900 MSL 20nm out, and a clearance to fly the approach and missed approach, if necessary.

Once established inbound at the DWFAP, at or below 70 knots (ground speed), a descent from 900MSL to 500MSL can be initiated.

If there are no obstacles within .5nm of course, and the radar and GPS are in agreement within .2nm for the destination target, a further descent from 500MSL to 200RA (radio altitude) can be made.

Radio altitude, from a radio or radar altimeter, is the actual height of the aircraft above the surface, in this case the ocean. The radio altimeter is used to determine the height, while the radar is used to identify obstructions. It’s a dynamic environment and just because an approach was clear of obstacles the day before doesn’t mean a drill ship wasn’t repositioned overnight.

At 1.1nm out, a right or left 30-degree turn is made to avoid overflying the destination, hence the name “Delta 30”. The heading change still has the aircraft converging with the destination, with the MAP (missed approach point) being .6nm away. At the MAP, one can proceed visually to land or go missed approach.

An OSAP is a great procedural tool for the trained two-pilot IFR crew in the offshore environment, providing precision approach-like minimums.

(These views and opinions are my own and do not necessarily reflect the views of Era.)

 

The rig looms ahead after shooting an OSAP Delta 30 instrument approach.  Photo by Paul Patrone

The rig looms ahead after shooting an OSAP Delta 30 instrument approach.  Photo by Paul Petrone

Markus Lavenson is currently flying for Era Helicopters as a captain in the Sikorsky S92 and Leonardo Helicopters AW139 in Alaska and the Gulf of Mexico in oil and gas support missions. His varied career began shortly after graduating from the University of California at Davis, and has included everything from flight instruction and powerline patrol to HEMS and external load operations. His more than 10,000 hours of flight time comes from more than a dozen different types of helicopters and airplanes. Holding an ATP helicopter and commercial multi-engine fixed-wing, he also is a flight instructor fixed-wing and instrument flight instructor helicopters. Lavenson enjoys the intricate work of helicopter instrument flying, whether it’s to an airport on Alaska’s North Slope or one he creates to an oil rig hundreds of miles offshore.

Tips for long cross-country flights

Because I take my helicopter where the work is, I often do long cross-country flights between my permanent and various temporary bases of operation. (After a lot of careful consideration, I’ve decided that it’s safer and more cost-effective to fly the helicopter from point to point than to buy a custom trailer and tow it.) I’ve been making cross-country flights in excess of 500 miles since 2004 and, for six consecutive years, made an annual round trip between the Phoenix area (where I lived) and north central Washington state (where I now live) for cherry drying work. Nowadays, I make an annual round trip between north central Washington and the Sacramento area for frost control. I flew solo on about half of these long flights; the other half was usually spent with a low-time pilot building PIC time at the controls while I tried not to be bored (or sometimes sick from PIO—long story for another time).

I flew home from California in late April. It was another solo flight, one that I’d been looking forward to mostly because I would be doing all the flying. And, instead of the 5-6 hour direct flight, I planned to fly west and then north up the California and Oregon coasts before turning inland again. Total flight time would be about 6-7 hours.

CA Coast

My first look at the California coast on a recent flight from the Sacramento area to Washington State.

Although the flight wasn’t as pleasant and uneventful as I’d hoped, I’m not complaining. But it did remind me of some tips I could share with other pilots preparing to do long cross-country flights.

Planning the Flight

Whether you plan to file a flight plan (which I recommend doing) or not, it’s important to plan for the flight. This pretty much goes without saying. In addition to the usual things to check in advance–weather, fuel availability, TFRs, route options–consider the following:

  • Make your flight segments shorter than they have to be. Sure, Robinson Helicopter claims I can get 16 gallons per hour in my R44 so I should be able to fly 3 hours (less 20 minutes reserve) between stops. But do I really want to fly that long without a break? Probably not–especially after those first two cups of coffee. Yet I’ve seen more than a few flight plans that had us in the air as long as possible.
  • Don’t just study your route before the trip—study everything around it. How many times have I tried to fly up or down the coast, only to be forced inland by a typical “marine layer” of fog? Too many to count. I’ve learned to study my route and alternate routes that would be easy to get to if I needed to change course.
  • Know where the fuel is along the way. Do you think you could make a planned fuel stop if you hit  30 mph headwinds that weren’t in the forecast (or flight plan)? This happened to me on my April flight. I was lucky that there were several airports with fuel along my planned route so I could stop sooner than expected.

Preparing for the Flight

Once you’ve planned the flight, you can prepare the aircraft for conducting the flight.

  • Gather and prepare your charts. If you use paper charts, mark them up with your intended route and fold them with the route easy to access. Then stack them in the order of use. That’s how I used to do it when I used paper. Sure beats fumbling around one-handed. Fortunately, we’re in the 21st century and have tools like Foreflight to provide accurate, up-to-date charts. Make sure you’ve loaded and updated all the charts you’ll need. Use the flight planning tools to mark your route. Then make sure you’re fully charged up and, if necessary, have backup power available. A backup device is handy, too. I use, in order: Foreflight on my iPad, Foreflight on my iPhone, and a panel mounted Garmin 430 GPS.
  • Make an airport and frequency list. I don’t do this much anymore–Foreflight makes it easy to get this info on the fly–but when I used paper charts, I also made a list of all the airports along the way that included frequencies for CTAF (or tower) and AWOS/ASOS (or ATIS). I could then program all the airport codes into my Garmin 430 as a flight plan and make frequency changes as I flew from one airport to the next.
  • Bring oil. I use W100Plus oil in my helicopter. It’s isn’t exactly easy to find. That’s why I usually bring along a quart for every expected fuel stop. That’s not to say that I’ll use it all, but it’s there when I need it.
  • Pack snacks. I always have a small cooler on board for long flights and do my best to fill it with ice (or frozen water bottles) and good snacks before I go. Even if you planned a meal stop along the way, circumstances might prevent you from making that stop. Maybe you had to change your route. Maybe the restaurant closed 30 minutes before you arrived. Or maybe the restaurant that was supposed to be a quarter-mile south is really more than a mile and a half from the only airport gate on the north end of the field. Bringing beverages like water or Gatorade-like drinks is also important. You don’t want to get dehydrated.
  • Pack an overnight bag. If you weren’t planning an overnight stay, pretend you were. A change of clothes, toothbrush, and credit card can make an unscheduled overnight stop a lot more pleasant. And if you think roughing it might be necessary, consider a sleeping bag or bedroll, either of which can make sleeping in an FBO–or the helicopter–a lot more comfortable.
  • Pack an emergency kit. I’ve spent so much time flying over remote areas that I forget that many pilots don’t. My helicopter has an emergency kit under the pilot seat that includes a first aid kit and equipment like fire starters, a signal mirror, a “space blanket,” energy bars, water, and so on. If weight is a factor–and it certainly is in my R44–you’ll have to limit what you bring. But some essentials can save your life if you’re forced to land in the middle of nowhere.
  • Make sure any required power supplies, cables, or batteries are handy. If you rely on electronic devices for navigation, you’d better make sure you’ve got back up power for them. My iPad’s battery can’t survive a 7-hour flight with the screen turned on and the GPS running. I use USB cables hooked up to a power supply to keep the battery charged. If you have a battery-powered GPS, make sure you have a spare set of batteries.
  • Set up your tunes. I listen to music or podcasts when I fly solo. My aircraft’s intercom system automatically cuts the music sound when a radio transmission comes through. Handy.

During the Flight

It’s during the flight that your preparation will really pay off. If you’ve done everything right, you’ll be prepared for anything.

  • Open your flight plan. I recommend filing and opening a flight plan for each segment of the flight. Again, with a tool like Foreflight this is very easy. I can open and close a flight plan with a few taps on my iPad screen. This beats the frustration of trying to reach Flight Service on the radio in a mountainous area when only 700 feet off the ground.
  • Remember that your flight plan is not carved in stone. I can’t tell you how many flight plans prepared by pilots who were accompanying me that went out the window before the second fuel stop. Stuff happens–usually related to weather–and changes are a fact of cross-country flying life. The only time I’ve ever done a long cross-country flight plan exactly as planned was on one trip from Wenatchee, WA (EAT) to Phoenix, AZ (PHX), and that’s because our straight line route across the Nevada desert didn’t have any other options for fuel stops. We had to do it as planned.
  • Know when to pull the plug and wait it out. Weather an issue? While scud running is something we’ve all probably done at one time or another, it probably isn’t something we should be doing. Tired? Tired pilots make mistakes. When low visibility, severe turbulence, or simple pilot fatigue makes flying dangerous, it’s time to set the ship down and take a break. If you did all your homework before the flight, you should know whether there’s an airport nearby to make the wait a little more comfortable. I remember unplanned overnight stays in Rosamond, CA (not recommended) and Mammoth Lakes, CA (which would have been nicer if I’d been prepared for snow).

Experience Is Everything

Low Clouds

Hard to believe that only a few hours after hitting the coast I was forced inland by low clouds and rainy weather.

My April flight was a mixed bag. It started with a beautiful but slightly hazy dawn just west of Sacramento, a gorgeous morning on the coast, moderate turbulence with strong headwinds, low clouds, hazy coastal weather, drizzly rain, more low clouds, even lower clouds (and scud running), and bumpy air on a cloudy day. If you’re interested in details, you can read about it in my blog. Although it isn’t common, it is possible for me to have a perfectly uneventful cross-country flight of 500 miles or more in a day.

If you do enough long cross-country flights, planning and conducting a flight becomes second nature. I’m always thinking about what’s up ahead and working on ways to get more information about alternative routes when things aren’t looking as good as you want them to. I’ve occasionally used my phone to call AWOS and ATIS systems at airports I think might be along a better route. I use radar in Foreflight to get a feel for how weather is moving and where it might be better or worse than I am. I’ll change altitude to avoid mechanical turbulence. If I have to do any scud running, I do it slowly and carefully, always aware of exactly where I am and where I can go if things get worse.

It’s all about planning and preparing and using your experience to handle unexpected situations as they come up. After a while, there’s very little than can surprise you.

Fly the cloud: Controlling whiteout and brownout

When landing helicopters in potential obscuration conditions, there are two techniques that have worked well for me over the years.  Whether the rotor wash kicks up loose earth causing a brownout or snow causing a whiteout, the techniques used to mitigate the obscuration are alike. While best to avoid these conditions by having ground personnel pack the snow, wet down a dusty area or find another landing zone, there are ways to manage the risk.

Unless you have a wheeled helicopter and a surface for a safe run-on landing, you likely need to land with zero groundspeed. This can be done safely using one of these techniques, without the risk of losing visual references and basically becoming IMC in a hover.

The Shallow Approach

The shallow approach is my preferred method in flatter terrain and a large area without obstructions.

Before discussing the actual approach, the “rotor wash contact point” should be understood. This is the point where the rotor wash meets the ground, and where the obscuration is formed. Its position, relative to the aircraft, is a function of aircraft airspeed, tilt of the rotor disc, and surface winds. All these variables affect where on the ground the obscuration will be formed and where it will drift after being formed. For example, decreasing airspeed or moving the cyclic aft will move the rotor wash contact point closer and more beneath the aircraft. The pilot can control the position of the obscuration cloud, by managing airspeed and the fore/aft position of the rotor disc.

This picture demonstrates the snow cloud being formed perpendicular to the rotor disc. Though this is actually a takeoff and not a landing, the pilot is using proper technique to maintain required visibility and surface references under applicable FAA regulations (FAR 91.155, 91.157, 135.205, and 135.207).

This picture demonstrates the snow cloud being formed perpendicular to the rotor disc. Though this is actually a takeoff and not a landing, the pilot is using proper technique to maintain required visibility and surface references under applicable FAA regulations (FAR 91.155, 91.157, 135.205, and 135.207).

As the approach is made, allow the aircraft to gradually slow down as you near the landing area.  Looking to the side, you will see the obscuration cloud catching up from behind as you slow. Allow the natural drag of the aircraft to be the cause of slowing, not aft cyclic. Any use of aft cyclic will quickly move rotor wash contact point, and thus the obscuration cloud, forward.

With practice it is possible to make a shallow approach to your precise landing spot without aft cyclic, resulting in a touchdown with the obscuration just reaching the mast area. One caveat is that you need to be sure of your touchdown area; this is not the time for a slope landing or to be unsure if it is a suitable landing area. The procedure is to touch down just as the groundspeed reaches zero, without ever having the rotor disc tilt aft of horizontal.

The wind can be beneficial or detrimental, so be sure to make the approach into the wind, even if just a few knots. A headwind will help keep the obscuration aft as long as possible, and help slow down the helicopter to a zero groundspeed without aft cyclic. If the wind is strong you may even be able to hover, keeping the cloud aft. If you need to slow a little quicker during the approach, use a little pedal to get out of trim and increase the drag. If I’m solo I will use the same pedal as the side I’m sitting on, to better see the obscuration cloud behind. If I have another person on board, I will use opposite pedal so that I can better see the landing area, having them watch the cloud.

For training purposes, I have flown over a snowy field at 50 feet and practiced moving the snowy obscuration cloud fore and aft, using the cyclic, but always keeping it behind. With practice you can position it and keep it exactly where you want as you make your approach. Think of it as flying two objects, the helicopter and the cloud.

The Steep Approach

This is a good technique when the area does not allow for a shallow approach, when unsure of the actual landing area, or when there is a hardpan of dirt or snow just below the loose stuff.  This technique does require more aircraft performance than the shallow approach technique, and an extended period of time hovering out of ground effect. Realistically, I do this technique about 80 percent of the time, and the shallow technique about 20 percent.

Make a slow and steep approach to your landing area, keeping the descent rate less than 300 feet per minute; settling with power considerations. Terminate to a hover, typically between 20 and 100 feet, at the first sign of an obscuration forming on the surface. The height this occurs is a good indicator of how bad the obscuration potential is. (I had a rule of thumb flying EMS at night: anything more than 75 feet was unacceptable and I would opt for another LZ.) Hold the hover as the obscuration dissipates. If there is a hardpan under the loose dirt or snow, it will get better. Adjust your altitude as necessary to remain above and clear of the obscuration. In a no-wind condition, it may take a couple of minutes for the obscuration to dissipate.

The fire truck wet down the area prior to the EMS Bell222A landing, helping mitigate the potential for a brownout.

The fire truck wet down the area prior to the EMS Bell222A landing, helping mitigate the potential for a brownout.

If the obscuration dissipates and you think it safe to land, find an object very close to your landing spot to use as a visual reference, preferably just a few feet in front of you at the 2 to 3 o’clock position (sitting right side). A rock, bush, twig will work; anything that won’t blow away. If the rotor wash unexpectedly kicks up more dirt or snow during landing, this may be your only reference to control the helicopter.

Should you ever find yourself in instrument conditions in a hover from a brownout or whiteout, you basically have two not very good options. If still high above the ground, pull max power and hopefully fly out of it without losing control, or if close to the ground lower collective and hopefully land without rolling the helicopter. Be safe and remember:  it’s better to use superior judgment, avoiding the necessity of superior skill.

(These views and opinions are my own and do not necessarily reflect the views of Era.)

CH53s landing in dusty conditions at sunset in Iraq, by pilot Dan Adams.

CH53s landing in dusty conditions at sunset in Iraq, by pilot Dan Adams.

Markus Lavenson is currently flying for Era Helicopters as a captain in the Sikorsky S92 and Leonardo Helicopters AW139 in Alaska and the Gulf of Mexico in oil and gas support missions. His varied career began shortly after graduating from the University of California at Davis, and has included everything from flight instruction and powerline patrol to HEMS and external load operations. His more than 10,000 hours of flight time comes from more than a dozen different types of helicopters and airplanes. Holding an ATP helicopter and commercial multi-engine fixed-wing, he also is a flight instructor fixed-wing and instrument flight instructor helicopters. Lavenson enjoys the intricate work of helicopter instrument flying, whether it’s to an airport on Alaska’s North Slope or one he creates to an oil rig hundreds of miles offshore.

Just say no to traffic patterns

Over the past eight or so years, I’ve done more than my fair share of long cross-country flights with newly minted commercial pilots or CFIs. In most cases, the purpose of the flight was to reposition my helicopter at a temporary base of operations 500 or more miles away and the typically 300-hour pilot on board with me was interested in building R44 time. I was on board as a passenger and got a chance to observe the things these pilots did–or didn’t do. I think the fact that I’ve never been a flight instructor gives me a unique perspective on what I observed.

One thing I’ve come to realize is that typical flight training does very little to prepare students for a commercial flying career. Instead, students are taught to perform maneuvers “by the book,” often so they can teach those maneuvers to their own students in the future. While it’s obviously important to know how to perform maneuvers properly, there are other concerns that are important to commercial pilots. In my upcoming posts for Hover Power, I’ll tackle a few of them, starting with traffic patterns.

I can tell lots of stories about new commercial pilots and CFIs entering traffic patterns to land for fuel at nontowered airports in the middle of nowhere. I can even tell you about the pilot who landed on the numbers of an empty airport’s runway, hover-taxied to the taxiway, and then hover-taxied a half mile down the taxiway to reach the midfield fuel island. They did this because that’s what they had been trained to do. That’s all they knew about landing at airports.

Our flight training teaches us a few things about airport operations, most of which are school-established routines at the handful of airports where we train. There’s a procedure for departing flight school helipads and there may be a procedure for traveling to a practice field nearby. Once there, it’s traffic patterns, over and over. Normal landing and takeoff, steep approach, maximum performance takeoff, run-on landing, quick stop, autorotation–all of these standard maneuvers are taught as part of a traffic pattern. It gets ingrained into our minds that any time we want to land at an airport, we need to enter a traffic pattern.

The reality is very different. Remember, FAR Part 91.129 (f)(2) states, “Avoid the flow of fixed-wing aircraft, if operating a helicopter.” Your flight school may have complied with this requirement by doing a modified traffic pattern at the airport, operating at a lower altitude than the typical airplane traffic pattern altitude of 1,000 feet, or landing on a taxiway rather than a runway. But despite any modifications, it’s still a traffic pattern.

But is a traffic pattern required for landing? No.

Experienced commercial pilots–and their savvier clients–know that traffic patterns waste time. And while the pilot might not be concerned about an extra few minutes to make a landing, the person paying for the flight will be. Why waste time flying around the airport before landing at it? Instead, fly directly to or near your destination and land there.

Before I go on, take a moment to consider why airplanes use traffic patterns. They enter on a 45-degree angle to the pattern to help them see other traffic already in the pattern. They then follow the same course as the other planes so there are no surprises. This is especially important at nontowered airports that don’t have controllers keeping an eye out for traffic conflicts.

But helicopters are avoiding this flow, normally by flying beneath the airplane TPA. As long as they stay away from areas where airplanes might be flying–remember, avoid the flow–they don’t need to worry much about airplane traffic. Instead, they need to look out for other helicopters and obstacles closer to the ground. If a runway crossing is required, special vigilance is needed to make sure an airplane (or helicopter) isn’t using the runway to take off or land. Obviously, communication is important, especially at a busy airport when a runway crossing is involved.

Now you might be thinking that this advice only applies to nontowered airports, where the pilot is free to do what he thinks is best for the flight. But this can also apply to towered airports.

Airport controllers who are accustomed to helicopter traffic and understand helicopter capabilities may instruct you to fly to and land at your destination on the field. You must be prepared to do this, even at an airport you’ve never been to before. That’s part of what your preflight planning is all about. Consult airport diagrams or even satellite images of the airport. Know where you’ll be flying from and where you need to park. Imagine the route to that spot. Be sure to take note of where the tower is–it’s often a great landmark for navigating while close to the ground. Never assume the controller will put you in a traffic pattern. And don’t be afraid to admit you’re unfamiliar if you didn’t do your homework or if things in real life look different from how they looked on paper or a computer screen.

What if a controller does instruct you to enter a traffic pattern and you don’t want to? As amazing as this might seem to new pilots, you can ask the controller to allow you to go direct to your airport destination.

I’ll never forget the flight I had one day as a passenger on my friend Jim’s Hughes 500c. Jim was a retired airline pilot who had been flying helicopters for at least 10 years. We were flying into Prescott Airport (PRC) in Arizona for lunch. When Jim called the tower, he asked for landing at the restaurant. The controller told Jim to enter a traffic pattern that would have required him to fly all the way around the airport, taking him at least 10 minutes out of his way. “Negative,” Jim barked into his microphone. “One-Two-Three-Alpha-Bravo is a helicopter. We want to land direct at the restaurant.” A new pilot at the time, I was shocked by his tone of voice. There was an uncomfortable silence and then the controller came back on and told him he could fly direct to restaurant parking.

 

The airport diagram for Prescott. The X marks the location of the restaurant and we were coming in from the west. Runways 21L and 21R were active. The tower instructed us to fly all the way around the south end of the airport, at least three miles out, to get into a pattern for Runway 21.

The airport diagram for Prescott. The X marks the location of the restaurant and we were coming in from the west. Runways 21L and 21R were active. The tower instructed us to fly all the way around the south end of the airport, at least three miles out, to get into a pattern for Runway 21.

 

Will the tower always grant your request? It depends on the situation. If a runway crossing is involved and the airport is busy with traffic, they might not. It might be safer or more convenient for them to keep you in a pattern with the airplanes. But it can’t hurt to ask, although I don’t think I’d be as aggressive as Jim was that day.

One of the big challenges of becoming a commercial helicopter pilot is thinking like a commercial helicopter pilot. There are things we can do that seem to conflict with what we were taught. Landing at airports without the formality of a traffic pattern is one of them.

Downwind takeoffs and the inherent danger involved

Humans like to push limits. Many have found themselves coasting into the next gas station on fumes, or worse, on the side of the highway. Sadly, this is the same mindset we can fall in to with downwind takeoffs. “I had no problem with a 5 or 6 knot tailwind takeoff last time,” or “I’ve taken off with a 10 knot tailwind. I don’t know why another 5 knots would hurt anything.” You get the point. “Permissible” downwind takeoff limits have often been debated. After all, the only thing two helicopter pilots can agree on is what the third one is doing wrong.

Our self-rationalization can get us in trouble in a hurry. What was a 5 knot tailwind takeoff one day will build progressively until you “accidentally” find out just what that tailwind limit is! I’m not implying that a 3 to 5 knot tailwind takeoff will get you hurt or killed. What I am saying is don’t fall prey to that “I’ll just go a little more this time” mentality that has been known to find its way inside helicopter cabins. It exists and sadly I see it more frequently than I care to admit.

THE MECHANICS

If a picture is worth a thousand words a diagram is worth a thousand explanations (or at least one). Let’s take a look at the mechanics of downwind takeoffs from a technical, yet practical explanation with a basic graphic representation.

Looking at this generic diagram we see three different helicopters each with a certain amount of power being used depending on the airspeed of the helicopter or the relative wind the blades are utilizing. At first sight of the diagram it should remind you of a basic power curve diagram and the fact that our wonderful machines are the only vehicle known to man that take more power to go slower. The power required curve could represent TQ (torque) required for a turbine helicopter or MP (manifold pressure) required. You will see at the bottom of the power required curve we have the “bucket-speed” or the speed at which we get the greatest airspeed for the smallest amount of power required. This “bucket-speed” area should be familiar as it is normally the best autorotative speed range as well. Looking at Helicopter #1 we see a helicopter at or near max power while in a 0-airspeed hover; in or out of ground effect, it makes no difference for this explanation. Granted, it will not always take max power to hover but consider Helicopter #1 at or very near max power for this explanation. Following along with the example helicopters you will see that helicopter #2 now has 15 knots of forward or headwind airspeed and the amount of power required is substantially less than the power required for that 0-airspeed hover. This concept in and of itself is no surprise (or shouldn’t be) to even the most novice students. It is helicopter #3 where we can get into trouble!

Looking at helicopter #3 we see that we have 15 knots of reward or tailwind airspeed. Looking at the power required we see that it is a mirror image of the power required for helicopter #2. It takes the same amount of power, in theory, to hover with a 15 knot tailwind as it does a 15 knot headwind. If you do this bring your tap shoes because you will be dancing on the pedals. (For the sake of aerodynamic argument tail rotor authority and increases in power required with use of the tail rotor are excluded from the equation.) Another way to look at this explanation is that the blades don’t care where the 15 knots of wind is coming from; in essence, with a 15 knot tailwind you could visualize the retreating and advancing blades (as you know them to be) have essentially traded places. I’m certainly not telling you to make a habit of hovering with a tailwind! A host of factors dictate why you shouldn’t, including loss of tail rotor effectiveness issues; yaw stability; longitudinal stability issues due to wind getting under (or over) large stabilizer surfaces; and potential TOT and compressor stall issues in turbine machines.

So, if we have a 15 knot tailwind as seen with helicopter #3 and we commence a downwind takeoff the rotor system is starting with a minus 15 knots of “support,” and therefore must outrun the tailwind and lose the translational lift that it had while stationary. Guess what? That takes more power! Essentially by taking off with this 15 knot tailwind you must use the power necessary to reach the power required area of a 0-airspeed helicopter as we described with helicopter #1. At this point you have a ground speed of 15 knots but the rotor system is experiencing a forward relative airflow of zero; you are getting no help from translational lift, and soon the helicopter will begin to descend. Remember where you are at this point; at or near max power. With the helicopter sinking you add more power, which increases the need for tail rotor robbing you of even more power. This is why I referenced “at or near max power” above. If you were faced with this situation, heavy, and in less than ideal performance conditions you may not have enough power and pedal to get you “over the hump” of the zero airspeed point. This dangerous and often overlooked downwind takeoff condition sets the table for a hazardous cycle.takeoff cycle

While many have fallen prey to pushing the limit with the low fuel light in their car, one must realize that pushing the limit with downwind takeoffs can lead to disastrous results. We must resist the temptation to gradually increase our accepted risk level regarding downwind takeoffs. Obviously with the right power margin and ideal conditions taking off with a certain amount of tailwind speed gradient is possible and can be made safely. It is human nature that we must avoid.

As always, I may be alone, but I doubt it. What say you?

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