What To Do In Case Of An Electrical Failure

14 Feb 20 14 Comments

NASA’s Aviation Safety Reporting System (ASRS) have an interesting series in Callback, in which they publish the first half of a story, based on ASRS reports, to the point where a specific decision must be made or a situation managed. The reader can then consider what he or she might have done to resolve the situation before reading what the reporting pilot actually did.

The interactions in the February 2020 issue include one on a total electrical failure which gives precious little detail.

Total Electrical Failure PA32 Cherokee Private Pilot’s Report

While flying a filed IFR flight plan [in IMC], I experienced total electrical failure, resulting in [minimal] instruments and no radios operating.

What Would You Have Done?

Unrelated photograph of a Douglas DC-3 at Gibraltar, courtesy of the Imperial War Museum, because I couldn’t think of a way to show an aircraft without power that wasn’t just black.

This reminded me of a recent AOPA installment of the Real Pilot Story called Powerless Over Paris. I should note this is Paris, Texas, not Paris, France, so the airspace is not quite as busy as you might think. Nevertheless, it’s quite an unexpected solution from ATC.

In Powerless Over Paris, Dr. Peter Edenhoffer relives the moment his airplane suffered a complete electrical failure in heavy instrument meteorological conditions (IMC) at night. As he speaks about the flight, Edenhoffer shares his thoughts and actions, including a fleeting moment of doubt about his chances for surviving the dilemma. However, with a little luck and creativity he and the air traffic controllers on duty finally established contact. But, would Edenhoffer be able to find the airport and land?

Hear the story first hand from the pilot and air traffic controllers involved. AOPA Air Safety Institute executive director Richard McSpadden praised the pilot and controllers for their resourcefulness in tackling a difficult situation. “The pilot’s focus on maintaining positive aircraft control in hard IMC while troubleshooting a critical electrical failure is a testament to the impact quality training and pilot proficiency have on safety. In addition, the controllers’ ability to think on their feet outside the norm reflects a collaborative intensity that permeates the aviation community and makes us safer,” said McSpadden. In 2018, air traffic controllers Charlie Porter, Phil Enis, Hugh Hunton, and Bryan Beck received the prestigious President’s Award from the National Air Traffic Controllers Association (NATCA) for their heroic efforts in bringing pilot Edenhoffer to a safe landing.

You can watch the AOPA video here (if you are reading this on the mailing list, you may need to click through to this post):

I’m glad to see such initiatives meant to help private pilots think about scenarios before they find themselves in trouble.

But I’m also interested to hear what you might do in the PA32 Cherokee that’s just suffered a total electrical failure. I’ll post the ASRS response in the comments in the next few days.

Also tell me what you might do in an airliner, where rather more “bells and whistles” have been lost. I suppose “pull over and contact the automobile association” isn’t the right answer…

Category: Demystifying,


  • I’m not a pilot, but I would probably bring up the GPS app on my phone that shows heading, altitude, magnetic bearing, accelerations and rotations. Not as good as an artificial horizon, but I’d hope better than nothing.

    I’ve also got full national maps on the phone as downloads, so even without cell contact I’d know where I was, including terrain altitude.

  • As a result of this article I’ve also tried out various artificial horizon apps, and one which works off magnetic declination and the accelerometers, seems to do a fair job of tracking horizon even when I whirl the phone round at odd angles and at speed.

    I wouldn’t for a moment suggest as a primary instrument, but a good fallback?

  • Let’s look at what these minimal instruments are.

    *Air Speed Indicator*, *Altimeter* and maybe Vertical Speed Indicator should still be working.
    The Magnetic compass is working.
    “Most small aircraft depend on air-driven gyro instruments powered by vacuum produced by an engine-driven air pump.” This means the gyro instruments, Heading Indicator and the Attitude Indicator (articificial horizon), should still be working as well!
    With an operational flashlight in the cockpit, I can actually read the instruments, if IMC means dark night.

    If I have an iPad mounted on the yoke with navigation up and running, I’m in luck, but “minimal instruments” doesn’t sound like I’d have one. But I probably have a mobile phone I can use.

  • Things have changed. Mobile phones were a novelty in my days. When “on” in the air, they tried to lock on to the nearest cell. Since the aircraft would have been moving and able to receive many cells to lock on to simultaneously, it would jump from one cell to another; a reliable phone contact would have been dubious. It could also have interfered with the VHF, but if the aircraft’s electrical power has gone that is irrelevant.
    Over open water it may just have worked: the number of cells that would be in range would be limited and contact more stable.
    I have tried this out myself, so this is not guesswork but we are now on the 4th generation of mobiles, with 5 on the horizon. My experiment related to mobile (cell-) phones of the 2nd generation.
    There are national differences: In Europe, on an IFR flight plan, there would have been an absolute requirement to check the weather at destination and at least one alternate. The alternat(s) would have been entered on the flight plan. For a single-engine C177, on an IFR flight plan, the need to have a good idea of actual and forecast weather, would be a legal requirement here, never mind its obvious necessity as a safety precaution. I may be wrong, but my admitted limited experience in the USA would seem to point to a somewhat less regulated situation. It is also, in Europe, not usual to fly IFR, in IMC, at night, to a destination which does not have an operational ATC. Runway lights here generally are not switched on by “clicking” the mike on a particular frequency. That may seem pedantic, but can make all the difference in a situation like the good doctor encoutered.
    Having said all that, the people involved obviously did a very good and highly professional job. Which had a happy ending.
    In a multi-crew, multi-engine airliner the operation is far more regulated. And of course the aircraft have multiple systems, electical systems usually are split and distributed over different “buses”, with an “ermergency bus” for good measure. The system would be powered by more than one alternator, so even in the event of a short, there is a good chance that some basic instruments and communications will remain available. The aircraft batteries must be able to provide emergency power to the standby electrical systems for at least 30 minutes, that is a legal requirement.
    This is a reason why a commercial aircraft, if a crew had left the power on inadvertently for a prolonged period, may not be started with a GPU and dispatched. The batteries must be exchanged and the depleted ones given a full charging cycle. On some aircraft that I have operated an APU, if installed, may have had limitations, e.g. there may have been a restriction on the maximum operational altitude in flight, but if installed a GPU can provide electrical power, in some cases nearly full power except maybe some “load shedding” items such as the galley.
    But, all said and done, this flight had a good ending. ATC handled the situation admirably and so did the pilot who kept his cool. He will be a good doctor to be at the side of a patient in case of a sudden medical emergency!

  • Forgot to mention: Some aircraft, especially on “ETOPS” have an emergency alternator that operates on a windvane. Normally retracted, it can be extended in case of an emergency since when over the ocean it may not be possible to reach an airport within 30 minutes (of battery power). And descending to a lower altitude in order to be able to use the APU – if still functional – would reduce their endurance.
    In the old days, if vacuum driven instrujments were the last resort, the way to attract the attention of ATC was to fly a triangle with one minute legs. I forgot which way, clockwise or anti-clockwise was the procedure to indicate a com failure or an emergency.
    The British aerobatic ace Neill Williams once had to use this procedure when, in a DH Vampire at night, above thick cloud cover, he lost all electrics.
    A bomber was sent to guide him to the runway where he nearly crashed when the bomber crew forgot to take their wake turbulence into account and made a full-power wave off. The slipstream threw the Vampire virtually inverted, in very poor weather, on short finals with gear and flaps down. Williams still managed to correct and landed safely.
    Of course, nowadays if it is only a transmitter faIlure, the pilot can still listen to ATC. If the communications set is faulty, but the nav systems operate, (s)he can switch to the ATIS and squawk 7600. ATC will communicate instructions on the ATIS and TVOR frequencies. In the good old days ATC still would make much more use of primary radar; nowadays, I guess they will have to wheel the set out of a half-forgotten recess, remove the dust and hope that eventually the valves will come back to life.
    Or call the air force, they should still have them.
    The transponder will be of no use in case of a total electrical failure.

    • It occurs to me that the phone trouble you describe is why communication via text messages worked while a phne call would not: it requires a far shorter connection to any one cell to complete successfully.

      A wind-driven emergency alternator such as you describe is offered for various small aircraft (including the PA-32) to the tune of $2600 or 2000€, which would make the answer to the ASRS problem quite simple if installed.

      If there was “total electrical failure”, wouldn’t that also affect the spark plugs? Aircraft engines don’t run on diesel fuel, after all!

      • > If there was “total electrical failure”, wouldn’t that also affect the spark plugs? Aircraft engines don’t run on diesel fuel, after all!

        No, because the spark plugs in an aircraft don’t run off the battery or the normal alternator circuit- they run off magnetos installed directly on the engine’s output shaft, which are completely independent from any other component in the system. Unless there was a failure specifically in both magneto coils, and as long as the engine is turning, the spark plugs should fire.

      • Yes. Text messages are store and forward, which means they will sit on your phone (or central exchange) untill the connection comes up, then be forwarded. They are also very small in terms of total data (less than 250ms of voice), which makes them by far the best means of getting a message through if coverage is very patchy.

  • There’s one part of this story that to me as a retired mechanic is very troubling. That is never nailing down the cause of the intermittent electrical failure. As you say, you can’t pull over and call AA. I don’t have a solution but shrugged shoulders (Guam salute) is never a satisfying conclusion.

  • As Slava mentions: the ignition in piston engines installed in aircraft is provided by magnetos. They create a high voltage that provides the spark at the plugs. And Slava correctly mentions: The magnetos are totally independent from the aircraft electrical system. To add extra safety, before take-off the pilot will test the system by switching them off, one at the time of course. The erngine should continue running normally on either. Sylvia knows this, her Saratoga had that system as ALL light aircraft ast the time did. Turbine power was too expensive and smaller units had not yet been developed. Of course, now turboprops are more common.
    In the early days of motoring most cars also had magnetos. The electrical systems were not well developed. The engine would be started with a handle and cars were often laid up during the winter. Some expensive cars like Rolls-Royce had dual ignition: One was operated by a magneto, the other by the still common coil and distributor. “A Rolls-Royce does not break down, it fails to proceed.”
    But that is not all: Around 15, maybe 20 years ago some light aircraft were equipped with diesel engines. The advantage – I have not really been interested in this development, I am sure someone on this panel will be able to inform us more comprehensively – being that the diesel engine does not require any ignition at all, except maybe to start from cold. At the nearby Weston aerodrome where two of the Citations were based that I used to fly in my last active years were, I believe, two aircraft with diesels.
    They sounded more like turboprops and I guess that they ran on jet fuel. Another advantage because AVGAS is nearly phased out at many larger airports. But there were also (very) red faces: I cannot understand how engineers and aviation authorities could have overlooked this, but when the electrics of a diesel-powered aircraft failed, the engine stopped as well. The principle of a diesel engine is that the compression of the mixture in the cylinders heats it up sufficiently to cause spontaneous ignition. But that also means that the fuel and air mixture must be injected at very high pressure. The fuel pumps were driven by electricity, so an electrical failure also caused an engine failure. I have the feeling that the aviation community lost faith in diesel propulsion for aircraft. Of course, the C of A of all of them was susoeneded. I live quite near Weston and have not heard the distinctive sound of the diesels for quite some time now.

    • Rudy, diesel engines still exist for aviation, and, I believe, getting more common. I know a flight school 172 in my area with a 180HP diesel installed, although I don’t know the model; they are also apparently popularly installed on Diamond aircraft.

      Since I have no direct familiarity with those engines, I went trawling the internet for some details of their operation. I found this[1] link, which makes it clear both low- and high-pressure fuel pumps are driven by the engine directly, not electrically, and certainly not through the aircraft’s regular electrical system.

      I struggle to imagine how anyone thought an aircraft with an alternator-dependent fuel injector was a good idea, and would certainly think twice before flying in one. Is it possible those were experimental aircraft with standard automobile diesels installed?


  • Correction: A “GPU” is not part of the aircraft, it is ground-based.
    I mistakenly referred to “a GPU if installed”. I meant an APU, a small jet engine in the tail of the aircraft (the Fokker 50 had it in the right engine nacelle). This APU is one of the aircraft’s systems. It is not used for the propulsion, but to provide electrical power and air for the cabin. Some engines can be started on compressed air. The RR Spey, installed in e.g. the BAC 1-11, could be started on compressed air or electrically.
    GPU: Ground power unit.
    APU: Auxiliary power unit.

  • Ah, I learn something new all the time! I wasn’t aware of what magnetos are (I expected them to be coils), and I didn’t know that diesel engines are used in aircraft. They appear to have been more common in the time of flying boats and Zeppelins.

    It appears they’re being certified today, here’s an example excerpt from a 2012 type certificate: “The TD-300-B is a 4-stroke diesel cycle air-cooled engine (4HOA), with a secondary oil cooling system, and a displacement of 4972 cm3. The engine is equipped with a direct injection fuel system and turbocharger. The engine is a direct drive with four flat horizontally opposed cylinders. The engine has electronic engine control mode with a mechanical back-up mode.” I expect that the high pressure pump is driven off the crankshaft, as is the “mechanical back-up” regulation, so these would keep running without electricity.

    The only problem seems to be that when Diesel fuel is used, care must be taken for it to not become cloud in cold conditions – car diesel may lack the required additives in the summer months. No such problems with jet fuel, of course.

    So, good to know that in a small aircraft, the engine will keep running in the absence of power, although the fuel gauges may stop working, which means we have engine power, but we don’t know how long!

  • Thanks for the comments. As mentioned, I have never really paid much attention to diesel technology used in light aircraft. At the time when I still flew Citations from Weston (a 500, a Bravo and a converted 500 called “Stallion”, about 12 or 13 years ago, it was mentioned that one of them suffered an engine failure following electrical failure. Maybe I misunderstood, it may have been failure of an electronic control. No doubt, if this was the case, this possibility surely has been corrected. And so stand I: Corrected !

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