Too Quiet Part 3: "What's That Funny Smell?"

Lighthouse Casablanca, Morocco - photo by JoAnn Sturman

by S.R. Oberst

It was only a few months until my next engine failure. This one occurred while I was flying a functional check flight (FCF) on a helicopter returning from extended maintenance work, including an engine replacement. An FCF ensured that an aircraft was safe and ready to be used on operational missions.

When I first arrived in the unit over four years earlier, all senior pilots in our unit flew FCF missions. Unfortunately, in the post Viet Nam, Jimmy Carter era, Air Force pilots were bailing out of the service quickly. So, except for the Commander and the Operations Officer, I was the next senior pilot with just five years of flying experience. For the last six months in the unit, I was the FCF pilot for most of the flights required by the Chief of Maintenance.

The FCF pilot put the aircraft through various maneuvers depending on what had been done by maintenance. There were a number of power parameters that had to be checked following an engine replacement. After the ground checks of the engine went smoothly, I took off to an open area west of the base that we used for all FCF flights. This area provided an uninhabited area to land should anything go wrong.

One of the stress tests on the engine required putting the helicopter into a climb at maximum continuous power for a period of time. By the time this test was completed I was several thousand feet above the ground. When I lowered the collective at the end of the test, the engine did not react normally. I noticed the engine RPM fluctuated about 200 RPM up and down, while under normal operating conditions it should not fluctuate at all.

I lowered the collective immediately, began a descent, and retarded the engine throttle slightly to keep the engine disengaged from the transmission. If the engine did fail, the helicopter would not lose any rotor speed. Even though the engine had not failed, as a precaution I had the helicopter in autorotation. Due to the high altitude, time was not an issue. At a 1500 foot per minute rate of descent, I had over 3 minutes of preparation time.

I should note that few helicopter pilots practiced high altitude autorotations because it was not a standard training maneuver. Fortunately, I had experimented with dozens of these over the years while flying on many otherwise boring missile support missions. Although a violation of flight regulations, I felt that training for emergencies of all sorts, as well as learning how the helicopter performed, was a smart thing to do. It was a lot of fun flying in ways that stretched the aircraft’s capabilities, but it also made me a better pilot.

After entering the autorotation, I contacted the tower air traffic controller and indicated I was not declaring an emergency, but due to fluctuating engine speed, I was making a precautionary landing. The three minute decent seemed like an eternity, and I wondered if I would land with engine power or have to perform a power off autorotation. I tried to apply fuel using the manual fuel switch, but it had no effect on the fluctuating engine speed. When I started my descent, the helicopter was headed into a 15 knot head wind – perfect conditions for an autorotation. In order to stay positioned for a landing in the field below, I began a slow steady turn to the right. My plan was to turn about 180 degrees and fly away from the field. At about 1,000 feet above the ground I made another 180 degree turn and lined up for a landing into the wind.

The engine RPM was now lower than when I originally retarded the throttle. I still had plenty of time, so I rolled the throttle to full on. The engine did not respond. Now less than 500 feet above the ground, I did not want to risk the chance of the engine suddenly engaging, so I rolled the throttle to idle. The engine was much quieter as I focused on maintaining rotor speed, executed a smooth flare, rotated the helicopter to level 20 feet above the ground, and finally timed the upward pull on the collective to stop the descent and smoothly touchdown at about 5 knots.
Of the three engine failures I experienced, this was by far the simplest one to handle. Although, technically the engine never failed, once on the ground the throttle was not responsive.

Maintenance had to tow the aircraft over 6 miles back to the base. A post incident investigation revealed improperly installed compressor bleed valves. In addition, the fuel control had been incorrectly calibrated. The engine mechanic was once again A1C Potts, who had only recently regained his job status that had been taken away after my previous engine failure. (See The Other Left)

Two months later Airman Potts was arrested following a major drug investigation by the Air Force Office of Special Investigations. Potts was heavily into marijuana, not only smoking it in his dorm room, but distributing it as well. The OSI discovered over 15 kilos in his dorm room and pickup truck. As a routine, Potts worked the second shift and did not come to work until 2:00 PM each day. Apparently he smoked dope in the morning, came to work high, and then worked on helicopter engines. Potts went to a military prison, but not before implicating about a dozen other airmen who also enjoyed getting high in the dorm. Fortunately his weed induced maintenance errors were responsible for only the two engine failures which occurred when I was flying.

Epilogue

Several years later, as a flight evaluator, I was sent to a helicopter unit to give the Detachment Commander, Major Mack Jackson, his annual checkride. (See Ask Me No Questions) Of course, Mack’s autorotations were nearly perfect; however, he struggled with the hydraulics off approach to the extent that I had to take the controls from him and turn the hydraulics back on. “You know,” I said to him, “I never did get to show you how I do a hydraulics off approach when I flew with you that time at Hill AFB years ago, so I’ll take it around and show you one now. Oh, and by the way, before I have you shut off the hydraulic switch, it is this one here,” as I pointed to the switch at the top of the pedestal.

After my last engine failure, I flew another 1,200 hours without another before being assigned to a desk job. All three engine failures had some things in common: I was flying when they occurred, each failure was caused by someone doing something stupid, all on board walked away unharmed, and lastly, it sure gets quiet when the engine quits, perhaps Too Quiet.

Too Quiet, Part 2 - Your Other Left

Cauliflower in Souk, Fez, Morocco - photo by JoAnn Sturman

by Steven R. Oberst

It was over 4 years and 1,800 flying hours later before I experienced another engine failure. The flight was a support mission taking ten Air Force security police (SP) to a missile site undergoing maintenance. On the flight were nine SPs riding in the passenger compartment, which was all the aircraft could accommodate. This was a single pilot mission, so the lead SP NCO, SSgt Reed, was seated in the co-pilot’s left seat position.
I completed my flight planning and noted that the power margin for takeoff would be slim. With ten fully equipped SPs and a warm day, power available would be adequate, but the takeoff would require some finesse. My technique in this type of situation was to bring the helicopter to a hover then gently move it forward, maintaining close proximity to the ground during the initial part of the takeoff maneuver. This is called maintaining “ground effect” and results in increased rotor blade efficiency, which in turn reduces engine power required for takeoff.
All seemed normal with the helicopter as I hovered out to the helipad for takeoff. I gently nudged the cyclic, the primary flight control stick, forward and slowly began to accelerate without using any additional power. I achieved translational lift without adding any power. (As a helicopter moves forward, about 15-20 knots in the UH-1 Huey, the helicopter achieves “translational lift”, a state which provides extra lift for takeoff.) At about 50 feet above the ground and approaching 60 knots I felt comfortable enough to increase power slightly. As soon as I raised the collective I heard a loud bang.
Reacting instinctively I immediately lowered the collective and looked at the gauges. Sure enough, the engine had failed, and the sudden quiet was memorable. When the mishap happened, I was flying over a flat grassy area between the main runway and a taxiway - perfect terrain for a forced landing. While keeping the nose straight, I elected to use a series of short flares with the cyclic instead of the continuous flare used in a normal autorotation. This technique allowed me to avoid striking the ground with the tail rotor, since the helicopter’s nose up attitude necessarily placed the tail close to danger. The aircraft gross weight was near maximum, but the flat, grassy surface beneath would permit me to keep the airspeed at higher than normal, so we would not fall like a rock from 30 feet in the final stages of the autorotation. Immediately before touchdown with an airspeed of 25 knots, I leveled the helicopter and pulled up on the collective to slow our descent. The helicopter skids touched down and we slid about a 100 feet.
The time from engine failure to coming to a stop on the ground was probably less than 15 seconds. I remember how quiet it got when the engine stopped and how everything seemed to slow down as I maneuvered through those 50 feet to the ground. It happened so fast that by the time the SPs in the back realized what had happened, we were safely down. However, SSgt Reed who was seated in the front seat, had an entirely different view of things. “Captain,” he said afterward, “that scared the shit out of me, but nice job!”
The previous day our engine mechanic, A1C Potts, made an improper adjustment of the fuel control which resulted in a compressor stall (the loud bang I heard) and the engine failure. Airman Potts apparently turned the control clockwise instead of counterclockwise and then failed to properly document the aircraft forms. This meant the change was never signed off by a maintenance supervisor, and I had no knowledge of the maintenance work completed. Potts was given a written reprimand and placed back in a training status.
This time it was my smiling face in the MAC Flyer, but another bonus came a few weeks later. Driving across the base, I was caught by an SP on radar. I looked at my speedometer just before I pulled over. “Damn,” I thought, “37 in a 25 means a ticket for sure.” The SP came up to my door and was about to ask for license and registration when he recognized me. “Hi, Captain,” he said with a grin, “try to keep the speed down a little, Sir. See you later.” It was SSgt Reed.

Too Quiet Part 1 "Ask Me No Questions"

Ceiling Hassan II Mosque Casablanca - photo by JoAnn Sturman

By Steven R Oberst

“Autorotation is the state of flight where the main rotor system of a helicopter is being turned by the action of air moving up through the rotor rather than engine power driving the rotor.” --Wikipedia

Don’t be fooled by this simple definition. This “state of flight” cannot be sustained indefinitely, so powered flight, although less exciting, is preferable. However, in case the engine quits, it is desirable that the pilot have the ability to execute an autorotation to a safe landing (one that everyone walks away from). Autorotations were my favorite thing to do in a helicopter. Flying helicopters is fun, but doing autorotations is over-the-top fun. To me, entering an autorotation was like starting down the first big descent on a roller coaster ride, only unlike the coaster car, which hopefully stays on the tracks, helicopters have considerable maneuverability while in autorotation. Practicing autorotations is entertaining, but there is added adrenaline when you do one for real. Plus, in a Huey, the turbine engines are quite noisy, so when the engine quits the sudden quiet really gets your attention.

When I was learning to fly helicopters with the U.S. Army, it was the belief of many Army aviators that pilots would experience an engine failure every for every 1,000 hours of flight time. I never heard a similar axiom among Air Force helicopter pilots, so I surmised that maybe this was more of an indictment of Army maintenance than it was factual. However, ten years and 3,000 hours in single engine helicopters later, I had indeed experienced 3 engine failures.

First Failure: Ask Me No Questions…

In the early 1970s Air Force helicopter pilots graduating from the Army program at Ft Rucker, AL were sent to the 1550th Aircrew Training and Test Wing at Hill AFB, UT to learn the Air Force approach to helicopter flying. Think of it as a “re-blue-ing”. The duration of the training depended on the type of helicopter you would be flying at your next assignment, so for an H-1F Huey pilot, the program was six weeks long. Much of the time was dedicated to search and rescue training, but there was also time spent on emergency procedures. This was to ensure you learned how to perform these procedures the Air Force way. For example, the Army performed autorotations to the ground with the engine at idle. The Air Force used a power recovery method that resulted in power being reapplied near the end of the autorotation with the maneuver ending in a hover instead of on the ground. Near the end of my six week training program at Hill I was scheduled to fly on an emergency procedures training mission. I had not previously flown with the instructor for this flight, Captain Mack Jackson, or the other student, Captain Vince Baggit.

Mack was a better looking version of Robert Redford. He carried himself with a swagger that set him apart from the other instructors. Vince on the other hand had the look of someone who was perpetually bored. He had been flying a desk for five years. I had met both of them a few weeks earlier when a group of pilots gathered at the Hill Officers Club for the Wing Commander’s promotion party. Vince quickly let me know he felt that being in the six week training program was a waste of his time because he already knew how to fly search and rescue. Meanwhile I watched in awe as woman after woman literally threw herself at Mack during the evening.

We took off from Hill AFB on a summer afternoon and flew a short distance to the Ogden Municipal Airport to practice the emergency procedures. Vince was flying and I was sitting in the jump seat. Half way through the flight we would switch places. I noticed how relaxed Mack was. So much so that he even put his feet up on the dash while Vince was flying. Vince was not a particularly good pilot, and his performance on the emergency procedures was underwhelming, but Mack never said a word. This is cool I thought, an instructor who is so laid back, he just lets you fly.

When it was my turn to fly, I did several autorotations with no problems. Then I did a manual fuel approach to a slide landing, which was kind of a tricky maneuver in this particular Huey; however, Mack was so relaxed he had his feet up on the dash until just before I landed. A glance at Vince revealed that he was sound asleep in the jump seat. Our next practice emergency procedure was a hydraulics off approach and landing. Once the aircraft was established on the downwind leg of its traffic pattern, the standard procedure was for the instructor to identify the hydraulic switch located at the top of the pedestal between the pilots. Following an acknowledgement from the student pilot, the instructor would turn the switch off.

When I had turned the aircraft downwind, Mack, with his feet on the dash, merely said “Ready?” Before I could respond he reached over to the middle of the pedestal and turned off the main fuel switch. Within a couple of seconds the engine flamed out and it got quiet. All I could hear in that first moment in time was the swishing sound of the rotor blades. Then red cockpit warning lights started flashing and a warning horn started screeching, indicating the engine had failed. I found myself lowering the collective (power control), entering an autorotation, calling “Mayday” over the radio, and looking for a place to land. All I could see on my side of the helicopter were trees and the Ogden River. Finally Mack came to life. He got on the controls with me, but did not take them away from me. I said “Do you see a place to land?” Then he said “I’ve got the controls.” He entered a steep turn to the left towards Interstate 84. By some dumb luck or due to a higher authority’s intervention, there in front of us was an open grassy area inside an off-ramp cloverleaf. Mack dodged the light poles surrounding it and made a perfect power off, autorotation landing in the middle of the cloverleaf. We barely felt the touchdown.
I could not believe what had just happened in less than a minute. This idiot instructor had tried to kill us by turning off the fuel instead of the hydraulic switch, but had then redeemed himself by doing a perfect autorotation to the cloverleaf. Should I punch the guy or hug him? I did neither.

Mack calmly reported on the radio to the tower that we just had an engine failure, but had landed safely, giving them our location. A maintenance team was dispatched from Hill AFB along with a van to take us back to the base. The aircraft was thoroughly inspected. It was no surprise to me when maintenance could not find anything wrong. Another pilot was brought to the site the next morning. The aircraft engine was started and after determining that everything was operating normally, the pilot flew the helicopter back to the base. I was told by another instructor that the incident would be investigated.

I dreaded being interviewed about the incident because I was not going to lie about what happened, and I knew this would not be good for Mack’s career. I was only ten days from being done at Hill and moving on to my first flying assignment. To my surprise, no one ever asked to interview me or ask me any questions about the incident. Vince, who was asleep when the incident happened, was certain that the engine just flamed out on its own, which is exactly what he told me he said to the Major conducting the investigation. I guess the Major felt he did not need to bother with interviewing a mere second lieutenant. So, I never told anyone that Mack had turned off the main fuel switch and caused the engine to flame out.

The next month I saw Mack’s smiling face in the MAC Flyer (a monthly safety magazine published by the Military Airlift Command, forerunner to today’s Air Mobility Command). There on the page giving kudos to crews executing successful emergency landings was a short article about Mack’s successful autorotation to an Interstate cloverleaf following an engine failure (cause unknown).

Next Week: Part II of Too Quiet: "Your Other Left"

Chapter 3 Part 2 Charlie's Check Ride

Lizard in Costa Rica - photo by JoAnn Sturman

by S.R. Oberst

Charlie's check ride woes continue as he shows he is incompetent at any speed or altitude.


Although lasting only 50 minutes, it seemed like an eternity of instrument flying time. Charlie completed his second instrument approach, turned the controls over to me, and directed me to fly west to the planned area for the simulated search pattern. For his simulation Charlie picked a spot on the map as the last known location of a missing hiker. Upon arrival Charlie took the controls and began an expanding square search pattern. Expanding square search patterns begin at the probable location of the target and expand outward in concentric squares. Accurate navigation is required to monitor the aircraft’s position in the pattern. Charlie’s lack of rescue training and inattention to detail was apparent to me, but what about SK? Again Charlie failed to allow for the wind, and the pattern would have missed any poor, lost hiker who had gone north of the last known position. Charlie, however, declared the search a success. He stated that the lost hiker was in a clearing and would require extraction from the air with the rescue hoist. Charlie entered a high hover about 100 feet above the clearing and struggled mightily to hold the aircraft in position while our flight engineer, Sgt. Cable, lowered the rescue device and completed the simulated pick-up. During this “rescue” mission, I thought to myself that the lost hiker was lucky he was simulated and not real.

All this time SK had been sitting in the jump seat without taking notes. Since he had the helmet sun visor down, it was impossible to tell where his eyes were fixed. As we headed back to the base, SK finally spoke, “Let’s go by the emergency practice field for some EPs (emergency procedures).”
“What?” croaked Charlie, “EPs aren’t part of this evaluation!”
“They are, if I say they are,” SK replied.

As we approached the emergency practice field, SK told Charlie to land. We only allowed to do emergency procedures with an instructor or evaluator at the controls, so once we landed SK switched seats with me. I’ll never forget the next 20 minutes as long as I live. The first emergency procedure was a hydraulics off landing. For this EP, the helicopter hydraulic system actually was switched off. Most pilots found this to be a relatively simple EP, but you needed to remember not to fly too slow on the approach to landing, because the aircraft became difficult to control. Over compensating Charlie came in too fast and just as we were about to touch down at over 50 knots, SK thankfully took the controls. He simultaneously turned the hydraulics back on and climbed away from the landing area. Charlie blurted, “Why did you do that?”
SK merely replied, “You have the controls. Let’s go around and try a manual fuel approach.”

I should interject here, that for normal flight the F model Huey has a fuel system that automatically compensates for changes in the position of the collective control which is used to increase or decrease power. However, should the automatic fuel system fail, there is a manual fuel system. This system involves a switch on the head of the collective that moves up or down to increase or decrease the amount of fuel going to the engine. It requires the pilot to anticipate changes in power settings with an appropriate increase or decrease of the manual fuel button. Every F model Huey seems to have a manual fuel system with its own idiosyncrasies.

It took practice to master a manual fuel landing on any F model Huey, but the manual fuel system on Beaver 72 was notoriously fickle. I knew from previous practice flights it had a manual fuel system from hell. It seemed to store up pilot inputs with no corresponding change in operating RPM and then all of a sudden the inputs would kick in and the RPMs would increase wildly, requiring rapid pilot flight control adjustments. Charlie never practiced manual fuel landings and was unaware of the potential problem.

Charlie took off to fly a traffic pattern and set up for a manual fuel approach and landing. Once in manual fuel, Charlie appropriately set up a long shallow approach for a running or slide landing. If a pilot accurately anticipated the need to pull up the collective at the bottom of the approach, he would bump the manual fuel switch up just enough to increase the fuel in synchrony with the need for power. Charlie anticipated this need with several bumps up, but the manual fuel on old Beaver 72 seemed to ignore him, so Charlie kept applying more bumps. I sat there in the jump seat knowing what was going to happen. Suddenly, all of those stored bumps took effect and the engine started to accelerate quickly. Over the intercom I yelled, “RPM!” Charlie momentarily froze. Thankfully SK did not. He again took the controls with a sharp command, “I’ve got the controls,” and simultaneously pulled up the collective control to avoid an engine over-speed. He re-engaged the automatic fuel system and then completed the approach to landing at the practice field. Calmly SK said “Okay, Charlie, you have the controls back.”

The next emergency procedure was known as a hovering autorotation. It was done by holding the aircraft stationary at 5 feet above the ground and freeing the engine from the transmission by rapidly turning the throttle to the idle position. Good hovering “autos” result in a well timed increase of the collective control and a soft touchdown. Charlie must have been a mental wreck by now, so it was no surprise that he pulled the collective up too early, resulting in a free fall from 5 feet. We were over grass and no damage was done to the aircraft, but it was a poorly executed, sloppy maneuver.

The last EP was the basic straight ahead autorotation from 500 feet above the ground. Charlie had yet to deal correctly with the wind. The landing direction was 300 degrees and the winds were now about 20 knots at about 340 degrees. Since he would not be heading directly into the wind, Charlie needed to compensate for this fact. Normally at about 75 to 100 feet above the ground the pilot begins to flare the aircraft to slow the forward speed and descent. If you are directly into the wind, you can start your flare lower. But, if the wind is light or there is a crosswind you will need to start flaring earlier. Charlie must not have recognized the strength of the crosswind, so he started his flare too late. Needing a more aggressive flare to slow the aircraft, Charlie pulled back on the cyclic stick. As you guessed it, since he preferred to sit with the pilot seat as far forward as possible, the stick hit him in the stomach. He was forced to abandon the maneuver, add power, and go around for another attempt.

Overcompensating on the second attempt, Charlie flared too early and too high for a successful completion. If it had been a real engine failure or forced landing, we would not have walked away. SK had seen enough. He took the controls from Charlie and flew us back to the helipad next to the unit hangar.

In the debriefing room Charlie was uncharacteristically quiet. SK debriefed me first. He said I had done a good job with copilot duties during the instrument flight and simulated search and rescue mission. He said my crew discipline was excellent, noted my frequent intercom announcements to assist the pilot, and that I had made the “best of a difficult situation”. He then thanked me for the assertive “RPM” call during the manual fuel approach. I was excused from the debriefing room at that point, so I will never know what was said to Charlie about the check ride. However, as I was leaving the room I did hear SK start the debriefing by saying, “First of all, Captain Crown, that lieutenant is no dummy and he probably saved you from...” I closed the door.