Flying on coconut time

April 29, 2015 by Markus Lavenson

Fresh coconuts everywhere! We hadn’t had any fresh food in the last couple weeks, unless you count coleslaw; nothing lasts longer at sea than cabbage and carrots. I started up the Bell-Soloy helicopter to begin shuttling crew to a Pacific island atoll. We were going grocery shopping.

 

An uninhabited Pacific atoll

An uninhabited Pacific atoll

 

It was 1988 and we had been at sea almost two months and the holds were far from full. My job was to fly the helicopter in search of tuna, and then help catch them by herding them into the net. We were to fill the Maria Rosana II with about 1,300 tons of tuna. She was a fast 225-foot tuna clipper with a crew of 23, five speedboats, and a helicopter. We used a seine net almost a mile long and 500 feet deep, with one end attached to the skiff and the other to the ship. When setting the net, the skiff was released and the tuna boat would make a huge circle back to the skiff. A cable, which ran through metal rings all along the bottom of the net, was then winched, closing off the bottom of the net. The net was then pulled through a power block until the tuna were packed tight. They were then scooped out and funneled through a chute into a hold for freezing. Simple enough, except tuna are 47 mph fast and lately schools had been hard to find. Holds full or not, we would soon be low on ship fuel and have to return to port. After months of hard work, we could now have a little enjoyment. After all, how many people get to land on uninhabited Pacific atolls?

After shuttling several guys to the island, I shut down the helicopter and started walking around. The birds had never seen humans and were unafraid of us; we had to zigzag to avoid stepping on them. As I walked the oceanside I saw multitudes of fish and some very large and inquisitive moray eels. The lagoon side was full of baby sharks. It was pristine and untouched.

Back at the helicopter, the guys had already accumulated a very large pile of coconuts. The copilot side door had been installed (no dual controls), so we were able to fill that entire side of the cockpit with about 20 coconuts.  I then flew back to the ship, landed and then reached over to pop the door open, watching most the coconuts roll out onto the deck. The mechanic then reached in and got the few remaining stragglers. After many trips we had a few hundred coconuts all over the helideck. The helideck had a metal lip about 4 inches high around the edge and was cambered, which caused the coconuts to roll away from the helicopter. Soon, there was barely enough room to land.

 

Just before start up and flying coconuts to the boat

Just before start up and flying coconuts to the boat

 

Later that day our pleasure was ruined by learning we had to waste a day meeting up with a sister ship to get a needed part. Seems one of the refrigeration solenoid valves was bad. Our mood was quickly restored when some genius figured out gin went really well with coconut milk, likely the helicopter mechanic.

The next day, I flew to the other boat to get the part and while the other pilot cleared the deck, we chatted on the radio.

“Oh by the way, the stabilizer is busted” he said. The stabilizer is a U-shaped hydraulic flume tank near the stern, married to the inside hull of the boat. Tuna clippers are long and sleek; so without a working stabilizer there isn’t much roll stability.

I knew what that meant. But I asked how bad it was anyway.

“Well she is rolling a bit in this swell, just pick your moment and you should be okay.”

“How much is rolling a bit?” I said. He was really getting my attention now.

“Oh, about 30 degree each way, but she’ll settle down once in a while for you to land. No problem, just get the timing right.”

Nearing the boat, I could see they had recently set the net and were laying stern-to in a following swell. This was worst possible position and she was rolling heavily, but I noticed there were pauses. I made an approach, trying to gauge and anticipate the roll. Once over the actual helideck, it was a combination of looking at the horizon and down at the landing area. The deck was moving up and down a manageable 6 feet, but the roll was bad. It was necessary to wait until the deck was fairly level and within the slope limitations of the helicopter, and then get it down fast before the next roll.  As soon as the floats touched down, I quickly bottomed the collective before the next roll. The mechanic rushed out with cargo straps, cinching us to the deck, and I began the two-minute cool down. The ship then took a big roll, which was not a lot of fun; an idling helicopter on a 30-degree slope 35 feet above the ocean. I doubt I could ever get used to that. Soon we shut down and I went into the bridge to look at the inclinometer gauge, which measures the amount of roll. I could hardly believe it, but it was showing regular rolls to 28-degrees both ways; a 56-degree swing.

After the part had been loaded, I climbed back in and started the turbine. After bringing the rpm up to 100 percent, I signaled the mechanic to release the last remaining cargo strap. Waiting for the ship to level, I then applied max power and nosed her over.

After I cleared the ship, I radioed the other pilot. “Hey man, how long has it been like that?”

“It went out at the beginning of the trip about a month and half ago,” he said.

“ Well, if there was a tuna boat helicopter pilot hall of fame I would vote for you.”

“Ha, well the first week is rough, but you get used to it,” he said.

I wasn’t so sure I would get used to it.  Rick was one of our most senior pilots and had been doing this for more than six years and was very good.  I was sure glad our stabilizer was working, and made a mental note to buy some drinks for our chief engineer the next time we hit the beach.

The rest of the trip was uneventful, until we blew up one of the helicopter’s floats with a ¼ stick of dynamite….buts that’s for another blog.

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

Flying to the ship

Flying to the ship

Post your comments »

Doors-off flying

April 22, 2015 by Maria Langer

Summer is on its way and, in most parts of the northern hemisphere, that means warm weather will soon be upon us. Not every pilot is fortunate enough to fly a helicopter with air conditioning. When I lived and flew in Arizona, it was common for me to take all of the doors off my R44 in May and leave them off until September. It was that hot every single day. (And no, I don’t miss it one bit.)

Of course, pilots don’t need warm weather as a reason to take the doors off. Sometimes the mission you’re flying requires it. Aerial photography is a great example — there aren’t too many photographers who would be willing to pay hundreds of dollars an hour to fly with you and be forced to shoot photos through highly reflective, possibly scratched Plexiglas.

When you remove the doors from a helicopter, you add an element of risk to the flight. Fortunately, the risk can be controlled if you fully understand it and do what’s necessary to reduce or eliminate it. That’s what I want to touch upon in this post.

Loose objects

The most obvious risk is from loose objects blowing around the cockpit or, worse yet, exiting the aircraft. This is a real danger, especially if an object hits the tail rotor or someone/something on the ground.

Want some examples of how dangerous this can be?

  • NTSB WPR14CA363
    “While in cruise flight an unsecured jacket departed the helicopter through an open window. The tail rotor drive shaft sheared as a result of the jacket’s contact with the tail rotors. The pilot subsequently initiated a forced landing to an orchard where during landing, the main rotors struck and separated the tailboom.”
  • NTSB WPR13CA071
    “Prior to the flight, the doors were removed in order to make it easier for the passengers to board and exit the helicopter…. After the two passengers were transported to a work site location, the right rear passenger exited the helicopter and placed the headset on the hook located behind the front seats. After departing the site, about 3 to 5 minutes later while en route at an elevation of about 1,000 feet above ground level, the pilot felt something strike the helicopter. After landing and upon inspecting the helicopter, the pilot discovered that the right rear headset was missing and that the leading edge of the tail rotor had been damaged.”
  • NTSB LAX03TA150
    “While in cruise flight, the back door on the helicopter opened, and a flight jacket that had been unsecured in the back seat departed the helicopter and became entangled in the tail rotor assembly. The tail rotor assembly subsequently separated from the tail boom, and the pilot was unable to maintain control of the helicopter.”
  • NTSB FTW86LA047
    “The pilot failed to assure the cabin door was properly closed before flight, or the cabin door just popped open during flight, allowing an unsecured life vest to blow out the door and into the tail rotor blades. This resulted in the entire tail rotor assembly departing the helicopter.”

(As some of these examples show, you don’t need to have the doors removed to have an unsecured item depart the helicopter and get into the tail rotor.)

Robinson Helicopter warns about this in Safety Notice SN-30, “Loose Objects Can be Fatal.” It recommends that pilots firmly latch all doors and even goes so far to recommend that pilot never fly with a left door removed. (Remember, the tail rotor is on the left side in a Robinson and many other helicopter models.)

I know that my engine starting check list includes an item to assure that loose items are secure. Yours should, too. While this is always important, it’s vital for doors-off flight.

Be sure you warn passengers of the danger of an item exiting the aircraft. Even something as small as a lens cap or lens hood can do significant damage to the tail rotor in flight.

Never Exceed Speed

You might not realize this, but your helicopter’s never exceed speed might be reduced with the doors off. On a Robinson R44, for example, Vne is reduced to 100 knots with the doors off, even if other conditions such as altitude and temperature would allow a faster speed.

My understanding from the Robinson Factory Safety Course is that this reduction of Vne is for structural reasons. (If someone knows better, please correct me in the comments.) There’s more buffeting wind inside the cabin with one or more doors off than with all doors on.

Check the Pilot Operating Handbook for the aircraft you fly the next time you remove doors to make sure you don’t operate beyond doors-off Vne.

Securing Passengers

This might seem like a no-brainer, but if you’re going to remove doors, your passengers had better be secured in their seats with either seat belts or harnesses.

Because some of my aerial photography or video clients like a greater range of movement in their seats than seat belts allow, I have a mountain climbing harness with a suitable strap for securing it to the aircraft frame. I make this available to clients as an option if they don’t have their own. Under no circumstances do I allow my passengers to fly without being secured, especially when their doors are off.

Keep in mind that while a photographer might use a harness to secure himself in the aircraft, you must make sure he knows how to release the harness from the aircraft in the event of an emergency — just as your preflight briefing must tell passengers how to release their seat belts.

 

Dangling Seat Belts

Of course, it was my generous offering of a harness to a photographer that resulted in more than $2,000 of damage to my aircraft when he used the harness but failed to secure the seat belt at his seat. The seat belt buckle dangled outside the aircraft for the duration of our 90-minute video flight chasing racing trucks over desert terrain. On landing, the passenger side fuel tank and area just outside the door frame had at least 50 dings and paint chips in it. How he didn’t hear it repeatedly striking the aircraft near his head is something I’ll never figure out.

Of course, it was my fault for not catching this prior to starting up and taking off. Expensive lesson learned.

Conclusion

While I don’t think there’s anything wrong with taking the doors off a helicopter prior to flight, it does give the pilot more responsibilities to assure that everything is secure and all passengers are properly briefed.

Or isn’t that something we’re already supposed to be doing?

Post your comments »

Why wait?

April 15, 2015 by Matt Johnson

We have a lot of great safety related resources in the industry. If you are flying professionally and have made it to that career goal you set years ago you may be familiar with most of these great resources. However, for reasons I cannot fathom many of these great resources are only introduced after a pilot makes it to his or her career position, whether it is HEMS or another side of the industry. This has to change!

Any HEMS pilot is all too familiar with a risk assessment (RA) tool. In fact, the regulations now require their use. The use of a risk assessment tool is a reminder that every flight has some level of risk associated with it and can sometimes open one’s eyes to previously unforeseen safety culprits. Say what you will, but a properly utilized risk assessment tool can be a tremendous asset when utilized correctly. So, why wait? Why are we waiting until a pilot reaches that first HEMS job at 2,000 or more hours to introduce them to this risk management tool? Why do we have to wait until he hits the 2,000 hour mark to make him safe and professional?

So much time is spent with a new primary flight student on learning to fly that many important facets are being neglected. Any CFI will remember studying the laws of learning and particularly the law of primacy. It states that those things learned first tend to stick with the student throughout his or her flying career. Instead of waiting for 2,000 hours to pass, why not teach the importance of the risk-management process (and tool) from the very beginning? And I do mean from the very first flight; the new student watches the CFI conduct a preflight risk assessment and explains what he or she is doing and more importantly why they are doing it. I have heard of just a couple flight schools utilizing risk assessment tools with students for flight training and I strongly applaud them! Hopefully others will follow suit.

We have other amazing resources for students. The United States Helicopter Safety Team (USHST) does a great job of conducting and providing analysis of helicopter accidents for the purpose of distributing “lessons learned” type of information. This group has produced dozens of nice training bulletins and fact sheets. They should be mandatory reading for any new student. But sadly I am finding that many beginning pilots have no idea what the USHST is. Why wait? CFIs should take the time to introduce the USHST to all of their students. Their website provides mounds of good useful reading material.

Unfortunately air medical related accidents have surfaced on a near regular basis in the United States. Many of the accidents involve inadvertent entry into instrument meteorological conditions. Many in the industry have taken note and developed various mitigation strategies. One of those strategies is an absolutely ingenious concept developed by the National EMS Pilots Association (NEMSPA). This group of highly talented professionals created the Enroute Decision Point (EDP). Simply stated, this concept says that pilots should establish a “trigger-point” when flying in less than perfect weather conditions. Their recent campaign has pushed a “down by 30” concept. This philosophy says that when a pilot finds himself in a deteriorating weather condition that requires him to reduce airspeed by 30 knots it is time to land or turn-around–or go IFR if capable. This is a great concept so, why wait? Why are we as an industry waiting until a pilot reaches the HEMS pilot hour requirements before we teach him this life-saving technique? Inadvertent IMC accidents and are not limited to the HEMS part of the industry.

And finally, Matt Zuccaro and the other fine folks at Helicopter Association International (HAI) have developed the “Land & Live” program. This concept stresses the importance that a pilot should land the helicopter before the situation becomes an emergency, such as in the case of a chip-light, low-fuel, or weather situation. The program has a strong emphasis towards commercial operators to not have a punitive culture for pilots that use good judgment and make the decision to “Land & Live”. This concept may sound like common-sense to many but all too often we read of situations where the outcome could have been entirely different had a pilot used this simple concept. So, why wait? Why not introduce this philosophy very early on in a student’s training?

This article has covered just a sample of the various philosophies and techniques that are being used by the most experienced pilots in our industry. If I haven’t made it clear, we as an industry need to start teaching these and other great safety practices to student pilots very early in their training.

Post your comments »

Fly the cloud: Controlling whiteout and brownout

April 8, 2015 by Markus Lavenson

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.

Post your comments »

Just say no to traffic patterns

April 1, 2015 by Maria Langer

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.

Post your comments »

Downwind takeoffs and the inherent danger involved

March 25, 2015 by Matt Johnson

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?

Post your comments »

Goodbye Sikorsky S300

March 12, 2015 by Ian Twombly

The focus at last week’s Heli-Expo in Orlando was naturally on the larger end of the helicopter market, from the first public display of the AgustaWestland AW609 Tiltrotor to Airbus Helicopters’ snazzy unveil of the H160. But one of the more interesting moments came almost as a footnote at a poorly attended Sikorsky press conference.

“Everyone’s always interested in the lights,” said Dan Hunter, director of Sikorsky’s commercial line. Yet despite that interest, Sikorsky has all but killed the S300 and its derivatives. Hunter said the company won’t take any new orders, focusing instead of filling its very slim backlog that has come from foreign government sales as part of group buys. Hunter said Sikorsky is working hard to firm up the supply chain in order to produce these few orders, and to a certain extent, to fill parts requests.

And therein lies the good news for current S300 operators. What was a dire situation a year or two ago with parts availability and factory support now seems to be something less than an emergency situation. “We’re not there yet, but we’re working to get it done,” Hunter said. The same inventory and support goals for the company’s other products also extend to the S300 and its variants.

On some level, I don’t blame Sikorsky. The aftermarket support brings in about $10 million a year, Hunter said. For sake of comparison, that’s about the cost of a new S-76D. When the bosses are sitting in a board room trying to figure out where to allocate resources it’s hard to justify the expense of establishing an inventory and support staff for a business that brings in the same revenue as one additional airframe sale. Why give a business unit leader a few million bucks and tell her to spend all her time contracting and supporting a supply chain when you can give Jim an expense account and tell him to sell one more helicopter?

Which does open the question of why Sikorsky bought the type certificate in the first place. To that, Hunter says he is convinced that knowing what they knew at the time it was a good buy. Peel back the layers, he says, and problems started to emerge. The manufacturing process wasn’t up to Sikorsky standards, he said. No offense, Elmira.

So, does that mean the S300 and its cousins are destined for a long life of purgatory, existing only on a piece of paper? Maybe not. Hunter hinted many times that Sikorsky could offload the business at the right time. It might work under someone else, he said.

Post your comments »

The multiengine height-velocity diagram

February 6, 2015 by Markus Lavenson

The last two blogs provided great explanations of the height-velocity diagram as it pertains to single engine helicopters. So, let’s now take it a little further into the multiengine helicopter realm.

Just as with singles, you will typically find a H-V diagram for multiengine helicopters in the flight manual. However, unlike the singles, the H-V diagram for the multi is to insure a safe landing OEI (one engine inoperative), and not from an autorotation. Furthermore, whether or not the H-V diagram even applies is dependent on how well the aircraft can perform OEI. This performance is defined in a series of categories. If the multi is full-time Category B (as are all singles), or a part-time Cat B, then a H-V diagram limitation will apply; whereas, if Category A it will not. Basically, Cat A is where OEI performance is so good that the H-V is not applicable. Comparing three very different multiengine helicopters to highlights these differences.

The BO105CBS is full-time Cat B, with marginal OEI performance. Even in ideal conditions (light weight and low density altitude), it can barely hold altitude on one engine. Varying airspeed from Vy just a couple knots results in a descent. Approach and departure profiles AEO (all engines operating) need to be such that a quick transition can be made in accordance with the H-V diagram, in the event of an engine failure.

The Bell 412 is an example of a multi that can be operated Cat A or Cat B, depending on the weight, altitude, and temperature. At lower weights, altitudes, and temperatures it will have good enough OEI performance to qualify as a Cat A aircraft. However, in most day-to-day operations it is typically a Cat B aircraft, which means the H-V diagram would apply.

 

multi hv

Bell 412 H-V diagram

 

The AgustaWestland 139 is a true Cat A aircraft, although as with many other Cat A aircraft it is possible to find conditions that will push it into Cat B. The AW139 was largely designed to operate Cat A, in an offshore petroleum support environment with a high useful load (passengers, cargo, and fuel). It is capable of landing and taking off from helipads, while carrying up to 15 passengers, with Cat A performance.

 

AW139 height-velocity chart

AW139 H-V diagram

 

So, what is Cat A?  Cat A is where the aircraft has adequate performance capability for continued safe flight in the event of an engine failure, no matter when that failure occurs. While single engine and Cat B multiengine helicopters have no such assurances, the Cat A aircraft is able to ensure that a safe and normal landing can be made OEI at an airport or heliport.

In the event of an engine failure, different types or categories of helicopters dictate different courses of action in order to do the same thing: preserve rotor RPM. No matter the helicopter and its’ number of engines, Nr is the wing and it must be maintained. The single must obviously enter an autorotation. The Cat B multi must fly at or above Vy (best rate of climb OEI) in order to maintain or increase altitude, and then fly to an area where a safe landing can be made. During takeoff and landing while close to the ground and below Vy, an engine failure in a Cat B will likely result in a forced landing. Though not as dire as an autorotation, it is more of an event than the Cat A helicopter. The difference with the Cat A is that engine failure doesn’t dictate a forced landing. In the event of an engine failure during takeoff, a Cat A has the ability to either return to and safely stop at the takeoff area or to continue takeoff, climb and establish forward flight. In the event of an engine failure during landing, the Cat A can either land at the intended landing area or abort the approach and reestablish forward flight. Unlike Cat B, there is no exposure to the possibility of a forced landing, hence no H-V diagram.

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

Post your comments »

Maximum performance takeoffs and judgement calls

January 21, 2015 by Maria Langer

Ed note: In the last post we covered the mechanics of the Height-Velocity Diagram. Here author Maria Langer discusses an application of its use. 

This past summer, I was part of a helicopter rides gig at an airport event. There were three of us in Robinson R44 helicopters, working out of the same rather small landing zone, surrounded on three sides by parked planes and spectators. We timed our rides so that only one of us was on the ground at a time, sharing a 3-person ground crew consisting of a money person and two loaders. Yes, we did hot loading. (Techniques for doing that safely is fodder for an entirely different blog post.) The landing zone was secure so we didn’t need to worry about people wandering into our flight path or behind an idling helicopter.

The landing zone opened out into the airport taxiway, so there was a perfect departure path for textbook takeoffs: 5-10 feet off the ground to 45 knots, pitch to 60, and climb out. It was an almost ideal setup for rides and we did quite a few.

One of the pilots, however, was consulting a different page of the textbook: the one for maximum performance takeoffs. Rather than turning back to the taxiway and departing over it, he pulled pitch right over the landing zone, climbed straight up, and then took off toward the taxiway, over parked planes and some spectators. Each time he did it, he climbed straight up a little higher before moving out.

I was on my way in each time he departed and I witnessed him do this at least four times before I told him to stop. (I was the point of contact for the gig so I was in charge.) His immediate response on the radio was a simple “Okay.” But then he came back and asked why he couldn’t do a maximum performance takeoff.

It boggled my mind that he didn’t understand why what he was doing was not a good idea. The radio was busy and I kept it brief: “Because there’s no reason to.”

The Purpose

The Advanced Flight Maneuvers chapter of the FAA’s Helicopter Flying Handbook (FAA-H-8083-21A; download for free from the FAA) describes a maximum performance takeoff as follows:

A maximum performance takeoff is used to climb at a steep angle to clear barriers in the flightpath. It can be used when taking off from small areas surrounded by high obstacles. Allow for a vertical takeoff, although not preferred, if obstruction clearance could be in doubt. Before attempting a maximum performance takeoff, know thoroughly the capabilities and limitations of the equipment. Also consider the wind velocity, temperature, density altitude, gross weight, center of gravity (CG) location, and other factors affecting pilot technique and the performance of the helicopter.

This type of takeoff has a specific purpose: to clear barriers in the flight path. A pilot might use it when departing from a confined landing zone or if tailwind and load conditions make a departure away from obstacles unsafe.

The Risks

This is an “advanced” maneuver not only because it requires more skill than a normal takeoff but because it has additional risks. The Helicopter Flying Handbook goes on to say:

In light or no wind conditions, it might be necessary to operate in the crosshatched or shaded areas of the height/velocity diagram during the beginning of this maneuver. Therefore, be aware of the calculated risk when operating in these areas. An engine failure at a low altitude and airspeed could place the helicopter in a dangerous position, requiring a high degree of skill in making a safe autorotative landing.

And this is what my problem was. The pilot had purposely and unnecessarily decided to operate in the shaded area of the height velocity diagram with passengers on board over an airport ramp area filled with other aircraft and spectators.

Height Velocity diagram for a Robinson R44 Raven II. Flying straight up puts you right in the “Deadman’s Curve.”

Height Velocity diagram for a Robinson R44 Raven II. Flying straight up puts you right in the “Deadman’s Curve.”

Seeing what he was doing automatically put my brain into “what if” mode. If the engine failed when the helicopter was 50-75 feet off the ground with virtually no forward airspeed, that helicopter would come straight down, likely killing everyone on board. As moving parts came loose, they’d go flying through the air, striking aircraft and people. There were easily over 1,000 people, including many children, at the event. My imagination painted a very ugly picture of the aftermath.

What were the chances of such a thing happening? Admittedly very low. Engine failures in Robinson helicopters are rare.

But the risks inherent in this type of takeoff outweigh the risks associated with a normal takeoff that keeps the helicopter outside the shaded area of the height velocity diagram. Why take the risk?

Just Because You Can Do Something Doesn’t Mean You Should

This all comes back to one of the most important things we need to consider when flying: judgment.

I know why the pilot was doing the maximum performance takeoffs: he was putting on a show for the spectators. Everyone thinks helicopters are cool and everyone wants to see helicopters do something that airplanes can’t. Flying straight up is a good example. This pilot had decided to give the spectators a show.

While there’s nothing wrong with an experienced pilot showing off the capabilities of a helicopter, should that be done with passengers on board? In a crowded area? While performing a maneuver that puts the helicopter in a flight regime we’re taught to avoid?

A responsible pilot would say no.

A September 1999 article in AOPA’s Flight Training magazine by Robert N. Rossier discusses “Hazardous Attitudes.” In it, he describes the macho attitude. He says:

At the extreme end of the spectrum, people with a hazardous macho attitude will feel a need to continually prove that they are better pilots than others and will take foolish chances to demonstrate their superior ability.

Could this pilot’s desire to show off in front of spectators be a symptom of a macho attitude? Could it have affected his judgment? I think it is and it did.

Helicopters can perform a wide range of maneuvers that are simply impossible for other aircraft. As helicopter pilots, we’re often tempted to show off to others. But a responsible pilot knows how to ignore temptation and use good judgment when he flies. That’s the best way to stay safe.

Post your comments »

The mysteries of the height-velocity curve

December 17, 2014 by Matt Johnson

Call it what you want; height-velocity curve, dead-man’s curve or even limiting height-speed envelope for those who like sophisticated phrases. The “dead-man’s curve” is probably a carryover from our fixed-wing brethren while the industry generally accepts the simple reference of “H/V curve”. The inside of the curve is the area from which it will be difficult or nearly impossible to make a safe landing following an engine failure if you are in the same conditions depicted with respect to airspeed and altitude.

The H/V (height-velocity) diagram is a staple in the helicopter arena but sadly is often misunderstood by student and instructors alike. So, let’s take a look at what it is and how it is developed.

What is it?

The Height-Velocity diagram (curve) is a chart showing various heights above the ground with a combination of a velocity (indicated airspeed) where successful autorotation and landing is or is not possible. This magical combination of numbers yields two major regions on the chart; the area above the knee and the area below the knee. These areas are what actually plot much of the “curve”.  During initial helicopter certification, test pilots evaluate several characteristics of the helicopter that help determine the H/V curve. These factors include the helicopters initial response to a power loss, steady-state descent performance and power-off landing characteristics and capabilities.

Unknown to many, the development of the H/V curve and its associated number combinations is based on “pilot minimum skill level”. So, in a perfect world this means if the engine fails while I’m going this fast (KIAS) and at this height a pilot at a “minimum skill level” should be able to make a successful autorotation and hopefully some resemblance of a landing.

How do we define the pilot “minimum skill level?” That is a question I and many others can’t answer. Many will agree the current practical test standards are somewhat lacking and aren’t necessarily cultivating the “minimum skill level” necessary.

HVDiagramR44

No cookies for me please

To delve into this quandary let us recap the typical sequence of an autorotation training exercise. The instructor has the student line the helicopter up with the runway so that the power-recovery phase of the autorotation will occur as closely to the runway numbers as possible. Sound familiar? You know what I’m talking about, the “3, 2, 1, roll-off power” etc.

It’s the same thing with a 180-degree autorotation where the student is taught where to “fail” the engine based on tailwind strength and land at the “spot” within the practical test standard. Is there really anything practical about it?  Just what, if an engine failure occurs in the real world and the only spot you have is 600 feet directly below you? Could you get there? Safely? What about engine failures at night time with the same situation, the only place to go is directly below you or just out in front of you. If you remember anything from this article remember this, autorotations are like fingerprints in that no two are exactly the same.

Read the rest of this entry »

Post your comments »