AOPA Hover Power

I fly a Bell 206 JetRanger helicopter as a demonstration aircraft for my company’s autopilot and glass cockpit systems. It is equipped with a Wire Strike Protection System (WSPS) and many times I am asked what it is and how it works.

Bell 206 with Wire Strike Protection

The system on the Bell 206 has three main components: an upper cutter, lower cutter, and deflectors. Each cutter has a deflector that forces the wire into sharp high-tensile steel blades (they are rubber coated to prevent inadvertent injury to service personnel). An additional deflector strip runs vertically between the pilot and copilot windscreens to guide the wire to the upper cutter. On different helicopters other deflectors are mounted as necessary to protect critical areas. For example, on the toes of the skids to force a wire to go under the helicopter and stop it from getting caught between the skid gear and the fuselage.

It is a passive protection system that reduces the chances of an accident in the event that the helicopter is flown into horizontally strung wires. The key phrase is “reduces the chances” as the system is not 100-percent effective. In order to work properly the helicopter needs forward speed; faster speeds increase the probability of cutting the wire. Also the level of effectiveness is a function of several other factors including where the wire impacts the fuselage, the cable tension, and the diameter of the wire.

The US Army evaluated the WSPS by performing pendulum swing tests using a Bell OH-58 (basically a military version of the Bell 206). The tests went well and they adopted the system for use on U.S. Army helicopters. Since then several Army helicopters have hit wires that were then cut by the system resulting in no injuries and minimal to no aircraft damage. Several civilian helicopters equipped with the WSPS have cut wires and avoided an accident as well.

Of course the best protection from wire strikes is prevention. Some things to consider are only flying below 500 agl when it’s necessary, looking for poles because they are easier to spot than wires and when you need to fly low over wires cross at the poles or supporting structures. Additionally, when landing in unapproved areas be sure to perform a complete aerial reconnaissance. If your helicopter is equipped with wire strike protection it should be viewed as a last line of defense.

I was in a pilot lounge at a heliport where an operator was giving sightseeing rides when a pilot returned to the loading area after getting fuel. The loaders brought out five passengers and I heard the pilot say over the radio that they put too much fuel onboard and he could only take four passengers. Right then another pilot who worked for the sightseeing operation jumped up and said, “No, don’t take the passenger back. I’ll do the flight.” He ran out and told the pilot he would take over so the pilot could take a break. As I watched the helicopter lift off, the guy standing next to me (who was not a pilot) said, “Now there goes a real pilot.” I looked at him waiting for him to crack a smile or give me some signal he was kidding. He was serious.

I have known helicopter pilots who don’t think too much about gross weight. If it can hover, it will fly fine they would say.

Case in point, according to the NTSB the pilot of a Bell 206L departing on a sightseeing flight on a hot summer day lifted the helicopter to a hover and started a takeoff run. The pilot said it felt like the helicopter did not have full power and it did not gain altitude as it neared the end of the heliport. The tail rotor struck the edge of the pier. The helicopter then hit the water, the pilot deployed the floats, and the helicopter rolled inverted.

When the pilot was questioned about the lack of engine power, he stated that sometimes dirt or dust could lodge in the fuel system and then dislodge from the impact. When asked if the helicopter was overweight, the pilot stated no, because he was able to hover with an indicated turbine outlet temperature (TOT) of 720C and 92-percent torque.

Regarding the helicopter’s weight and balance, the pilot stated that he did not ask passengers their weight and did not have a scale at the heliport. Rather, he estimated the weight and balance. For the accident flight, he estimated 150 lb. per person, as there were three male passengers and three female passengers. After the accident, an FAA inspector questioned the passengers about their weights. The passengers reported their weights as 132 lb., 176 lb., 187 lb., 207 lb., 210 lb., and 213 lb. In addition, the pilot weighed about 190 lb. Although the pilot estimated 150 lb. per passenger, the average weight of the passengers was approximately 188 lbs. Those passengers plus fuel made the helicopter about 250 lbs. over gross weight at the time of the accident, not including the weight of clothing, personal effects, and baggage.

The FAA puts the standard average weight for operators with a no-carry-on bag program to 184 lb. in the summer and 189 lb. in the winter.

I remember in the mid-1990s Copter ILS approaches began showing up in the New York area. They came from an interpretation by the FAA’s Eastern Region of the Part 97 U.S. terminal instrument procedures (TERPS) that granted helicopters lower minimums. The prevailing thought was that because of a helicopter’s unique maneuvering capabilities the craft could safely operate with lower minimums. I had flown these approaches a couple of times and they seemed to work well.

The Copter ILS approach used the existing ILS, but allowed helicopters a DH of 100 feet and an RVR of not less than 1,200 feet. Although this was basically CAT 2 minimums there was no aircrew qualification required. Moreover, pilots were flying below 200 feet without visual reference to runways that did not have CAT 2 certification. So in 2000, (Copter ILS approaches had been flown for years without incident) citing concerns over technical issues such as signal strength and reliability below 200 feet, threshold clearances and lighting, the FAA issued a Notice to Airmen (NOTAM) that terminated the Copter ILS approaches.

Various industry groups worked with the FAA to help re-establish the lower minimums. Today there are Copter ILS approaches; however, they overlay CAT 2 approaches as this solves the technical TERPS issues. They also require special aircrew and aircraft qualification. An example is Ronald Reagan Washington National Airport (DCA) Copter ILS or LOC RWY 1 approach (www.aopa.org/members/airports/ustprocs.cfm?ID=DCA).

Lyn Burks has a passion for the helicopter industry. His aviation career began in early 1991 at the age of 23. Although he was a U.S. Marine from 1985 to 1989, he is civilian trained in Robinson Helicopters. During his initial years in the industry, he worked full time for a municipal fire rescue department. In 1999 he retired as a fire captain and entered aviation full time. Burks holds an ATP/CFII helicopter with nearly 6,000 hours of flying experience and recently he semi-retired from full- time employment as a corporate pilot flying an Agusta A109E. In addition to corporate flying, he has experience in several sectors of the helicopter industry including ENG, charter, utility, instruction, and a five-year stint in EMS flying the S76C+. Burks also is a helicopter industry recruiter who has written several online EBooks and articles about helicopter careers and organizes an annual career development and networking seminar.

Lyn Burks with an A109E

Burks’ Web site, JustHelicopters.com, has become an industry icon. The site was created in 1998 by retired helicopter pilot Bill Kellogg as a small free access Web information center and a place for people interested in helicopters to exchange ideas. In 2001 Burks took over the Web site and has expanded it into a leading online resource for the helicopter industry. He is also the owner and developer of another popular helicopter Web site, Verticalreference.com.

JustHelicopters.com hosts and administers two forums. The original one does not require a login and is very loosely moderated; nevertheless, professional courtesy is strongly suggested. However, beware that the discussions can sometimes be very heated and some of the posts are can get very critical of others. Although there are rules, rumors and gossip show up frequently. It can be very entertaining at times, however if you post something even a little controversial you should be thick skinned as some of the responses can be harsh.

The second forum requires a login, username, and password. As such, the topics and posts are much more professional and technical in nature. According to Burks, it is more suited for first-time users.

Burks recently expanded his network in two new directions with different media content. The first is the addition of Justhelicopters.TV, which is a Web site dedicated to helicopter industry related video content. The second is a media partnership with Rotorcraft Professional magazine, which is a popular helicopter industry trade journal. Burks says, “From print to Web to video, our goal is to offer something to everyone who enjoys and works in the world of helicopters.”

JustHelicopters.com is an ongoing project and has remained a free access site. The site contains a comprehensive list of helicopter resources, including articles, photo galleries, job postings, operator directories, flight schools, and salary information. Burks is continually adding and updating content and relies upon input from the helicopter community to keep the information current and pertinent.

You can visit the site at www.justhelicopters.com

Jim Thomas asked, “Are the hazards of a helicopter rotor blast taught to new students?” The answer is sometimes and sometimes not. Being dual rated, I understand the affect the rotor down wash can have on an airplane. As an instructor, it is always something I teach to students.

Wind direction and strength must be considered when hovering near other aircraft. For example, when hovering with a strong right crosswind, leave more room between other objects and left side of the helicopter. The rotor downwash will be very strong on the left side and very weak on the right side. I have had line personnel direct me to park too close to another aircraft that was downwind of the rotor wash. I would just touchdown in a better suited area and explain why once they approach the helicopter.  Some understood, some did not.

However, it’s not just parked airplanes that can get tossed around. I was on a hospital helipad with another helicopter when the other pilot needed to depart. While he was starting up I was busy finishing some paperwork. There were no obstacles and the wind was calm, so the last thing I expected was for him to depart directly over top of my parked helicopter. That’s exactly what he did causing the blades to flex down, and the fuselage to shake. I was sitting in the helicopter with the door open and fortunately was able to get it closed. If I were to guess, he couldn’t have been more than 10 feet above me. I never understood why he did that.

On another occasion, I was hover taxing along the edge of a ramp to parking when I noticed some smaller airplanes rocking a little and in front of me was a pilot with an open door. I moved out toward an empty taxiway and ATC immediately told me I was too close to an active taxiway. I explained why and he said, “Understand, but you can’t say there.”

It’s unfortunate that students are not taught more about this subject. However, many pilots are aware of their prop or rotor blast and act courteously and try to minimize the impact on others. However, some either don’t understand or care. To protect yourself and your aircraft around an airport or heliport, I think the best advice is to always assume you could be subject to a prop blast or rotor downwash.

There are some things that helicopter pilots do that are just not smart.

For example the pilot of a Robinson R22 Beta landed in a field to pick up some equipment and while he was there he decided to hot refuel. The pilot’s father drove a pickup truck equipped with an auxiliary fuel tank under the rotor disk of the running helicopter to accomplish the refueling. The pilot said he stayed at the controls of the helicopter and a wind gust caused the main-rotor blades to flex down, striking the top of the truck. Although no one was injured, the helicopter rolled to the right and into the truck resulting in structural damage to the helicopter. At the time this happened winds were reported from 170 degees at 18 knots, gusting to 25.

Another bad idea is leaving the cockpit while the engine is running and the rotor system is spinning. That’s how a pilot damaged an Enstrom 280X after landing in a corn field and getting out of the helicopter. In an interview with the NTSB, the pilot stated a gust of wind appeared and the main rotor severed the tail boom.

Another pilot preparing to lift-off in an S76 noticed a “door unsecured” indication on the instrument panel for the left cabin door. He brought the engines to idle and exited the cockpit to check the door. He re-closed the door and returned to the cockpit. However, the door open annunciation came on again. He then left the cockpit two or three times to deal with the door. He did not recall retarding the engine power control levers to ground idle before leaving the cockpit the final time.

The wheel-equipped helicopter started to move as the pilot was returning to the cockpit. He told the NTSB it was moving toward the edge of the elevated helipad. He managed to climb into the cockpit, but before he could regain control, the helicopter was on its side.

I can remember several times getting ready to depart and then realizing that I needed to check or do something. It is very tempting to just friction down the flight controls and get out. However, every time I consider doing that I think of what has happened to other pilots.

The majority of single-engine helicopters do not have autopilots installed. The few that do have autopilots (not counting experimental designs) use a series-parallel model. Even a simple two-axis system without a flight director can be somewhat complicated as it will have a series actuator and a parallel actuator for both pitch and roll.

In the case of the Sagem autopilot, the series actuator is known as a SEMA (Smart Electro Mechanical Actuator), the flight control tube is cut and the actuator inserted. SEMAs are fast moving with limited authority (plus or minus 3.5 mm). The parallel actuator is called a trim actuator and is normally attached to one end of the flight control tube.

When the pilot engages the pitch-and-roll switch, the two SEMA actuators (one for pitch, one for roll) provide a SAS (Stability Augmentation System) by making very small rapid movements that enhance stability through rate dampening. When the force trim switch is engaged, the two trim actuators will hold the cyclic control in that position. The trim actuator contains a spring-and-clutch mechanism that provides the force trim. If the pilot moves the cyclic control it will want to return to its original position.

The autopilot’s upper modes allow it to hold heading, a navigational course, altitude, and indicated airspeed. Heading and course are controlled by roll and only one of these can be active at a time. Altitude and airspeed are controlled by pitch and only one of these can be active at a time as well. In both of these modes it is normally the SEMA actuator that controls the rotor system while the trim actuator anchors the flight controls. When a SEMA is operating off its midpoint, the trim motor is activated to move the cyclic in the appropriate direction and amount to cause the SEMA to return to its center position, restoring full authority.

The autopilot computer receives data on airspeed, altitude, heading, and course and compares it to the value selected by the pilot. If there is a deviation, the autopilot computer sends the appropriate signal to the actuators which moves the rotor system in a direction to cancel the deviation. This allows the autopilot to maintain heading or course and altitude or airspeed.

This describes a very basic system. More advanced helicopter autopilots have flight directors, yaw servo actuators, and servo actuators that control the collective. There are also systems that will auto hover.

Inadvertent IMC accidents are a problem for helicopter EMS operations. Unfortunately, when the weather is bad sometimes the pressure to accept a flight can rise. The following illustrates what I mean.

According to the NTSB, on the night of Jan. 10, 2003, an air medical helicopter was dispatched from Salt Lake City to Wendover, UT (just more than 100 miles to the west).

After departure, the pilot contacted the Salt Lake City (SLC) air traffic control tower and requested an I-80 transition low-level westbound to Wendover. The tower instructed the pilot to hold east of SLC because of landing traffic. The pilot held at 700 ft agl for about 19 minutes while monitoring the tower and the ATIS frequencies. The pilot stated the weather drastically changed from two-mile visibility to 1/16-mile in fog. Because of the deteriorating weather, the pilot elected to abort the flight and return to the hospital. Returning to the dispatch center, he heard personnel discussing that another air medical service was attempting the flight. The pilot then contacted the other pilot on the radio and reported that he just aborted the same mission because the visibility had reduced to 1/16 miles. The other pilot stated he was going to try to get over the fog.

The other pilot contacted SLC tower for a departure clearance from the hospital. He was cleared to proceed toward SLC. The pilot requested a clearance to 7,000 or 8,000 feet. He was cleared for the ascent and instructed to remain east of SLC. The pilot reported that he attempted to climb; however, he would lose VFR and requested not to do that, but to transition through the SLC airspace to see if it cleared up any better. The tower advised the pilot that the visibility was 1/16-miles and to proceed inbound and remain east of SLC. The tower then asked the pilot if he could continue westbound and the pilot responded, “I’d like to give it a try if I could.”

The tower cleared the flight westbound with instructions to maintain VFR at or below 5,000 feet. A few minutes later the pilot stated he was on the west side of the airfield, and requested to return back to the east. The controller informed the pilot that she could not let him go east until he could see other aircraft on final approach to Runway 34R or she had a break in traffic large enough to get him back to the east side.

While holding, the pilot had the following conversation with his dispatch center:

“We are on the west side of the airport,” the pilot said. “Air Med got sent out for this same damn thing and then they called us to go out. Air Med turned around for low visibility, so they go shopping for another helicopter and we’re turning around at the west side airport. You know, it what’s their determination, you know.”

“I understand,” the dispatcher said. “Unfortunately, that happens all day long. A lot of the dispatch centers do it, but, so I understand that you are turning back 20.”

“I mean, they need help,” the pilot replied.

A few minutes later, the pilot told the tower, “I’m basically inadvertent IMC at this time and declaring an emergency.” Twelve seconds later, the tower asked the pilot whether he had Runway 34L in sight.

“That’s negative and I’m currently on a heading one-five-zero,” the pilot responded.

The tower instructed the pilot to turn right to a heading of 340 degrees for a vector toward SLC. The pilot did not acknowledge the instruction, and the tower controller again attempted to contact him. No further communications were received. The Salt Lake City police department received a 911 call from a witness reporting, “Very thick fog…the helicopter barely missed their trailers…fog is very thick can only see 40 feet ahead.”

The Agusta A109K2 twin-engine helicopter was destroyed when it impacted terrain while attempting to maneuver in dense fog. The instrument rated commercial pilot and the flight paramedic were fatally injured, and the flight nurse was seriously injured.

Most helicopter EMS programs operate under VFR only. With the high number of weather-related accidents lately, the question of mandating IFR operations is talked about a lot. I do not know of a study that compares weather-related accidents for VFR-only versus IFR helicopter EMS programs. My guess would be that IFR programs would have a lower rate of these kinds of accidents.

I have flown for two IFR programs, Mayo One (BK117 C1) and CareFlite Dallas (Augusta 109E). In both programs the pilots in general were more comfortable flying in lower weather. This is for several reasons, but mainly the extra training and the fact that they were flying a fully IFR-certified helicopter. Also, I think being IFR trained and experienced helps pilots make better go/no-go weather decisions.

Filing an IFR flight plan does take a few extra minutes. However, using the IFR system to respond to a trauma call (flight on a highway for example) is rarely done. In these cases the ground crew would have to transport the patient to the closest instrument approach (normally an airport). If we couldn’t save any time, we would advise the dispatcher that transport by ground would be faster. Time is critical and a responsible pilot must make sure not to risk delaying patient care. I seldom launched on a flight under IFR.

However, there were several times when after departing VFR and on the return flight to the hospital weather deteriorated. I would call approach and receive an IFR clearance and vectors to the hospital’s GPS approach. In general, I’d say that getting a pop up clearance was not a problem and caused minimal if any delay. Keep in mind this was Rochester, Minnesota; ATC was not as busy as some larger airports and very accommodating to Mayo One. In Dallas/Fort Worth (CareFlite) ATC was much busier but also very helpful. Here pilots are sometimes asked to turn to a different heading and may be asked to maintain VFR for a short period. Normally they will get you in the IFR system and to an instrument approach with minimal delay.

The IFR system is definitely more fixed-wing friendly. Compared to airplanes, helicopters operating under IFR is still relatively new. The development of low-level GPS routing and WAAS approaches will help change that in the future.

In general, I do not think EMS programs are able to justify the added cost of an IFR program by the increased number of flights (therefore revenue) that IFR capability brings. I think the more important point is the increased pilot proficiency it provides and the extra options it gives the pilot. In an industry that is always trying to cut costs I think highly of the programs that understand the benefits and increased safety that an IFR program brings. If I were to return to EMS flying I would definitely want to fly for an IFR program.

In response to my previous blog, Jon S. brought up some very good points. He questioned whether an EMS pilot would climb into the clouds, autopilot or not, if he or she would face an FAA violation for doing so. He is absolutely right as declaring an emergency does not guarantee a pilot won’t be cited with a violation. The FAA has taken the position that if the emergency is caused by the pilot’s action or inaction, then a violation is appropriate. In many cases the NTSB has upheld the FAA’s decision.

So how does this affect an EMS pilot’s decision making process? Well, in all the EMS Part 135 operations manuals I’ve read there is a defined procedure for inadvertent IMC. Basically, it is to climb, contact the nearest ATC, declare an emergency, and perform an instrument approach. In discussing this with other operators, I was told that the local FSDO has taken the position that if a pilot does the appropriate due diligence that they will not pursue a violation.

According to the NTSB, on June 8, 2008, an EMS pilot in Texas aborted a flight because of low clouds and fog encountered en route. The request was then made to a different operator. The second pilot was notified of the flight and performed a weather check for the route of flight. After his weather check, he contacted his company’s Enhanced Operational Control Center (EOCC) to discuss his weather observations and the previous turn down. Both the pilot and EOCC supervisor were observing 10 miles visibility and ceilings acceptable for the flight. At that time, the pilot or the supervisor did not understand the reason the other pilot turned down the flight. The pilot contacted EOCC a second time to discuss that the previous flight had been turned down because of fog. The pilot and the EOCC supervisor again discussed weather observations with the same conclusion, that the restriction to visibility reported by the previous flight was not observed by any official weather reporting station.

The Bell 407 crashed in densely forested terrain killing the pilot, flight nurse, and paramedic. Sheared treetops indicated initial impact occurred with the helicopter’s main rotor blade system in a straight nose-low attitude. It happened in the exact location where the other EMS pilot had encountered low clouds and lost reference to surface lights. The other pilot told the NTSB there were no traffic or weather concerns at the time of his departure. While en route, approximately five miles south of the hospital, at 1,400 feet he encountered wispy clouds. He descended to 1,200 feet and encountered more clouds, continued to descend to 1,000 feet and encountered even more clouds, and finally descended to 800 feet when the visibility decreased rapidly. He stated that he could see to the east but had lost his surface light reference. He turned immediately to the right, towards the freeway system, and was back in good weather. He stated that the low clouds and visibility were very sudden and dramatic.

Whether a potential FAA violation affected the accident pilot’s decisions that night will never be known. This kind of accident happens too often in EMS operations as some pilots obviously underestimate the potential for a CFIT accident. Better training would definitely help. I think climbing is normally the best option, however, Jon’s point is well taken and EMS pilots who could be put in an inadvertent IMC situation need to be sure they perform reasonable due diligence.

Another good question is whether all EMS operations should be flown under IFR. That’s coming up next.