Training day
I was teaching at a flight safety provider that included classroom instruction, a simulator session and 4 hours in the air.
My student had done well on the ground portions and equally well in the flight training. We’d flown about 2 hours, took a break for briefing and lunch and then took advantage of ‘actual’ instrument conditions to work on approaches and holds. All that was left was to fly back to our departure airport in the pilot’s newly purchased A36.
From our practice area in the west, we flew eastward on vectors for the approach. Our track would take us several miles north of the aerodrome, a dozen miles further east and then follow ATC-directed heading changes to intercept the final approach course inbound.
We were in solid cloud at 4,000 feet, about 2,500 feet above the flat terrain. The reported ceiling at our destination was good, about 1,200 feet AGL, with good visibility; the air was smooth and well above freezing temperature.
I don’t remember the engine sounding rough, just that it ‘sighed’ into a lower noise level and I was pushed forward into the shoulder harness. ‘We have an engine problem,’ I recall telling the pilot.
In a very quick scan, I saw most of the engine gauges appeared normal. The anomaly was the fuel flow needle, which had spun past the high-end red line. That was a major clue to the cause of the power loss but solving the power puzzle would have to wait.
As we rolled out, I could smell fuel!
Nearest airport
Time to show my age. This happened early in the GPS era, before the advent of moving map displays. At the time, most IFR aeroplanes had an automatic direction finder (ADF), a simple needle that pointed toward the transmitter of a non-directional beacon (NDB) on the AM radio band. In even older times this was called a ‘radio compass’.
It was common to use NDBs off your track to determine your approximate position. As you progressed along your flight path, the needle would slowly move until it was horizontal in the instrument, meaning that the beacon was off your wing in that direction. But it didn’t give distance, only relative bearing.
I’d tuned the ADF to the beacon at an airport several miles almost due north of our destination aerodrome. When the needle pointed toward my left wingtip I was between that airport and our destination. That gave me at least some way to track my progress on the easterly vector. Today’s pilots have much more information with a GPS.
Despite a great week training for emergencies, my student didn’t immediately respond when I told him of the power loss. He may have been startled by the change in status, perhaps even thinking more about the possible engine repair cost than getting the aeroplane – and us – on the ground with no further damage.
So I said, ‘I have the flight controls’ as I grasped the control wheel. I instinctively applied back pressure as the aeroplane decelerated. At the same time, I began a turn to the left until the ADF needle was pointing straight up, meaning I was heading directly toward that second aerodrome. It was the only thing I could positively locate with the panel of that day, the equivalent of hitting ‘nearest airport’ on a GPS and turning toward the result.
‘I’ve had a partial loss of engine power and am declaring an emergency,’ I told Approach Control. ‘I’m heading directly to Newton’ – that was the aerodrome north of our original destination. I quickly answered ATC’s request for the amount of fuel remaining and the number of souls onboard.
That’s when the controller issued a clearance that I rejected, although I understand why he did.
Emergency procedure
By this time, the pilot had caught up with our status. I talked him through the memory steps of the engine failure inflight checklist, but none of the actions – switching fuel tanks, turning on the boost pump, checking the ignition, activating alternate air – restored the lost power.
Responding to the off-the-scale fuel flow, I experimented with leaning the mixture to get the fuel flow down to a more combustible setting. But the fuel flow indication remained top-of-scale regardless of where I put the mixture control. It appeared that the power I had was all we were going to get.
Not having the tech (in those days) to be able to find out the distance to Newton, I asked the controller. The immediate reply was 7.4 miles. The wind was approximately from the north before the emergency began,so I asked for the distance to Jabara, our destination aerodrome. The reply was 7.3 miles. So Jabara was slightly closer and more importantly, would give me a tailwind instead of the headwind I was fighting toward the NDB to the north.
Command decisions
With this information, I changed plans. ‘I’m going to head toward Jabara,’ I told ATC. That’s when the controller issued a clearance that I rejected, although I understand why he did.
Put yourself behind the radar screen. The controller wants to help and, from their viewpoint, that means giving you radar vectors for a long, easy straight-in approach. So naturally, the controller replied, ‘Fly heading 150 degrees, radar vectors for the approach.’
But wait – that was pointing away from the aerodrome. I had some power, but not a lot and also no idea how long that reduced power might last. So I replied, ‘Negative, give me a vector direct to Jabara.’ Remember, in IMC I had no way to determine the direction to the aerodrome with the top-of-the-line (for the time) equipment on board.
As all this was happening, I had discovered that with the throttle and propeller controls fully forward, and fuel flow still unresponsive to the mixture control, the aeroplane would just hold level at 4,000 feet at best glide speed, which in this aeroplane was 110 knots. Any slower or faster than best glide and the aeroplane would descend; deviate by 5 knots and the vertical speed would change by 500 fpm.
We talk about best glide in the context of total power loss. But as a ‘least drag’ speed, it will get you close to the optimal vertical speed (climb or descent) for the power available, even when power is not ‘zero’. I hadn’t thought about it in those terms before that day.
That’s important because the controller, now pointing me directly toward the airport, again did what he thought was most helpful. Only a few miles from the airport, it seems reasonable to direct an easy, gradual descent. ‘Descend and maintain 2,200 feet,’ the controller directed.
‘Negative,’ I again told ATC. ‘I’m going to maintain 4,000 feet until you tell me I’m 2 miles from the airport, then I’ll descend out of the clouds and land.’
The reason was I still wasn’t certain the engine wouldn’t quit completely and I wanted to have as much altitude – and therefore options – that I could if that happened. I don’t fault the controller for trying to make things easy for me the best way he knows.
In more recent years I’ve worked with a controller who is also a flight instructor. His advice for ATC for a partial power loss in a single-engine aeroplane is to provide vectors directly to the nearest airport at the highest altitude available to allow the aircraft to spiral down over the airport to land.
What are the odds?
What are the odds you’ll find yourself with enough power to fly the aeroplane, albeit with little or no power in reserve, and need to make decisions that are often made for you in the event of total power failure? As it turns out, the chances are pretty good.
In 2011 the Australian Transport Safety Bureau (ATSB) published its landmark study, ‘Managing partial power loss after take-off in singleengine aircraft.’ This study confirmed that, among power loss events that resulted in an ATSB report, partial power loss occurred 3 times as frequently as total power loss.
The study goes into the hazards of partial power loss shortly after take-off, hazards heightened by the challenge of recognising sometimes subtle partial power loss indications. It stands to reason that partial power loss may be at least as likely as total engine failure in all phases of flight, leaving pilots with the possibility of exercising these sorts of command decisions.
Landing, and my mistake
Communication with the controller and remaining in command of the aircraft were both important throughout the ordeal. It was a balancing act of asking relevant questions and seeking additional information while using my own judgment rather than blindly doing what I was told.
So what happened and what was my major mistake? With the aeroplane’s owner again at the controls and me working the radio and monitoring the ‘big picture’, we proceeded at 4,000 feet directly toward the aerodrome until ATC said we were 2 miles out. Then we descended out of the clouds, visually acquired the runway and manoeuvred for an otherwise uneventful landing. That’s when I made my error.
As we rolled out, I could smell fuel! We taxied to the ramp and shut down. I popped open the door on the right side of the aircraft. The fuel smell was much stronger and after I got out, I saw the entire right-hand side of the fuselage was blue with 100LL fuel. It was coming from the engine compartment so I popped open the right cowling (Bonanzas allow opening the entire upper cowling).
The fuel line to the middle cylinder on the right side had come out of the fuel injector, allowing fuel to spray onto the engine and out the back of the engine compartment. This removed back pressure from the fuel lines, causing the fuel flow transducer to spin wildly and give that past-redline fuel flow indication.
I can see, perhaps, that in flight there may have been enough air flow through the cowling to prevent the draining fuel from creating a combustible mixture. However, once on the ground, I’m surprised it didn’t burst into flames. My mistake was not evacuating the aircraft as soon as it came to a stop on or just off the runway. If I ever again land with indications of excessive fuel loss, I won’t repeat that mistake.
Emergencies and command
It might be a partial power loss, or a total engine failure. It might be a completely different type of emergency, or an abnormal condition that, through escalation or distraction, may develop into an emergency. Whatever the scenario, assess the indications, aim for the best landing option, process any applicable checklist, tell the controller what you need and what you want to do. I learnt a lot when this happened to me.
Attempting to turn into taxiway Golf, the aircraft veered towards a drainage ditch.
