Mooney: Engine Failure on Take-Off

10 Apr 20 18 Comments

I was looking for something else entirely when I found the docket for this case, a Mooney crash in 2004. The NTSB report is only six pages and most of that is the standard form and bad pagination. I wouldn’t normally bother with a crash this simple but I found it intriguing how the docket information gives an insight as to the progress of the investigation.

The pilot had 656 hours total with four hours in the last 30 days, a pretty typical private pilot. He was rated for single-engine land planes and was instrument rated. The aircraft was a Mooney M20J, registration N302SB, with 4,500 hours.

The 11th of July 2004 dawned clear with calm winds, blue skies and ten miles visibility, a perfect day for flying. The pilot was departing from Hackettstown, New Jersey, a general aviation airfield with a 2,200 foot asphalt runway. The airfield elevation is 670 feet above sea level.

The previous day, the pilot had refuelled at Lawrence Municipal Airport (LWM) in Massachusetts and flown to Hackettstown Airport, where he spent the night.

He returned to Hackettstown Airport the next morning. At about 7am local time, he departed the airfield to return to Lawrence Municipal Airport. He took off from runway 23. However, as he reached about one hundred feet above the ground, the engine lost all power. The aircraft struck the rooftop of a house and crashed into the trees of their garden, about 200 feet past the departure end of the runway. The pilot suffered only minor injuries but the damage to the aircraft was substantial.

Here is his initial statement to the NTSB:

I went to the aircraft at approx 6:30 am EDT and performed a complete pre-flight and run up of the aircraft. Fuel was at 3/4 full and I did not take on fuel since leaving LWM the day before. Immediately after rotation, at an altitude of approx 100 feet above the runway, the engine quit. I switched tanks and lowered the nose and attempted to restart the engine. It did not restart.

The plane landed on the roof of a house and came to rest in a tree. I was able to get out of the aircraft myself. I was departing Hackettstown NJ N05 at approx 6:50 AM with LWM as my intended destination.

The wreckage of the aircraft and the engine were examined by an FAA inspector, who could not see any sign of pre-impact mechanical malfunctions.

Compression was attained on all cylinders. Valve train continuity was observed, and crankshaft rotation was verified. When rotated by hand, the single drive dual magneto produced spark at all lead ends. The top spark plugs were removed for inspection. Their electrodes were intact, and were light gray in color.

The owner of George’s Body Shop in Hackettstown was on site to help with the clean-up. He drained approximately 20 gallons of 100LL fuel out of the right fuel tank and “about nothing, maybe 4 or 5 gallons, from the left.” Whether or not the pilot did, in fact, remember to switch tanks, it certainly seemed to me like if he was set to the left tank for take off, he may have starved his engine of fuel because his fuel was balanced incorrectly.

Fuel samples taken from the crash site

However, the reality was simpler than that.

The inspector pulled out the fuel pump, which was in perfect working order. But when he manually [manhandled] the fuel pump, water spilled out of the fuel outlet port. He also found water in the gascolator (the fuel strainer). When he tipped it out, it came out to about six ounces (175 ml) of water.

Water can condense and accumulate in fuel tanks. A part of the pre-flight check is to check the sump drain, which is located at the lowest point in each fuel tank. When the fuel is all shaken up, it doesn’t do much good to take fuel from the sumps. However, after the aircraft has been sitting overnight, the water will settle at the bottom. This is why, as a part of the preflight checks, the pilot drains a small amount from the sump drain to verify that what he is seeing is, in fact, fuel, as a part of a standard pre-flight check. If there’s a small amount of water, you can usually just quickly drain it out using the sampler, as long as the second sampler from the sump is fuel. The sampler I used on the Saratoga was 50ml, about 1.6 ounces. Six ounces sounds like a lot to me and more than I think I’d be happy with finding in my sump checks.

This means there are two logical conclusions that can be made. The first is that there was enough water in the fuel to block the fuel flow, feeding water to the engine instead of 100LL, which doesn’t do anyone any good. The second is that despite the pilot’s report, he did not do a thorough preflight check. He did not check the fuel sumps. It turns out the Mooney also has a drain valve installed in the fuel selector valve assembly, which allows you to drain the lowest point in the fuel lines. He clearly didn’t drain this either.

Occurrence #1: LOSS OF ENGINE POWER(TOTAL) – NONMECHANICAL

Phase of Operation: TAKEOFF – INITIAL CLIMB

Findings
1. (C) FLUID,FUEL – CONTAMINATION,WATER
2. (C) AIRCRAFT PREFLIGHT – INADEQUATE – PILOT IN COMMAND

———-

Occurrence #2: FORCED LANDING Phase of Operation: DESCENT – EMERGENCY

———-

Occurrence #3: IN FLIGHT COLLISION WITH OBJECT

Phase of Operation: DESCENT – EMERGENCY

Findings
3. OBJECT – RESIDENCE
4. OBJECT – TREE(S)

The NTSB declared that the probable cause of the accident was the pilot’s inadequate preflight inspection, which resulted in the total loss of engine power due to fuel contamination, during the initial climb after take off.

Crash site

That’s the important point: the cause was not that there was water in the fuel, because it is impossible to guarantee that water won’t condense in the fuel tanks overnight. The real failure was not to check for it. Draining fuel from an aircraft is a trivial exercise. Recovering an aircraft in this state is an impossibility.

18 Comments

  • “…feeding water to the engine instead of 100LL, which doesn’t do anyone any good.”

    lol

  • A lot of accidents are caused by a whole chain of things going wrong before a plane falls out of the sky — but every now and then an accident comes from one dumb mistake.

    DId the report say anything about how long he’d owned that airplane? If he’d recently transitioned from a type without a central drain in addition to the one for each tank, he might not have learned the habit — although if he were that new to the aircraft he should have been working with a written checklist. OTOH, I wouldn’t have guessed that a fuel line on a plane that size would hold 175ml, so maybe he would have seen water if he’d sampled the left tank.

    That seems like a lot of water to have accumulated from condensation — but the table of vapor pressure of water in Wikipedia (since I can’t find the rubber bible I inherited) suggests that a drop of 10 Fahrenheit degrees (not large between day and night in the northeast US) could wring ~7ml of water out of a liter of saturated air at somewhere-around-room-temperature, and the report of the amount of fuel drained from each tank suggests there was ~55 liters of airspace in the left tank when the plane was shut down; if he’d flown through temperate humid air before leaving the plane overnight, 175 ml of condensate sounds plausible (even figuring there was some lost when the fuel system was disassembled). It’s not surprising he wanted to refuel at home (which might be cheaper), but not checking the drains was … dim.

    • Yes, I think that’s why this caught my eye. It was just one simple thing that caused the whole incident. That and the fact that he walked away.

  • There is not much to add to this account. The facts speak for themselves.
    Fuel contains small quantities of water. AVGAS and jet fuel can contain miniscule quantities in a dissolved state. Normally it goes unnoticed, but at prolonged flights at high altitudes the low temperature can cause condensation to occur. Most jet aircraft have fuel heaters installed. Engine oil is fed through a heat exchanger, this has therefore a double benefit: the engine oil is cooled and the fuel heated. When refueling the Citation 500 series and the Learjet 20 series, as well as other light turbo-powered aircraft, a very aggressive chemical had to be added to prevent growth of some sort of algae in the tank as well as prevent ice formation. We always carried boxes of aerosols with “Prist”. The end of a plastic tube had to be clipped on the filler nozzle. These aircraft had overwing refueling. We always had to take care of part-filling one, moving to the other side and back to prevent an imbalace that could cause a wingtip to drop on the tarmac. Most if not all larger jets have a central filler valve and refueling is done under pressure. Later the suppliers sold the fuel with the additives; before refueling we would be given a sample from a glass bowl at the bowser. We put a strip in the sample. If it was contaminated with a too high water content it would change colour to red. But even so, we always had to drain the tanks as part of the pre-flight checks for the first flight of the day.
    I still have a plexiglass drain tool.
    Even if an aircraft is flown every day, when the aircraft is parked overnight the air gets cooler and water can condensate.
    Large jets are not totally immune, either. I seem to remember that a BA Boeing 777 had a double flame-out on finals into Heathrom about 7 or 8 years ago. It had arrived from China. It crash-landed just short of the runway. Insofar as I remember there were no casualties.
    My very first job as a commercial pilot was flying advertsing banners.
    I will not mention the operator, in those days the company took a cavalier attidude towards maintenance. They owned about 25 or 30 Super Cubs and operated nearly non-stop from April until October. During the winter season most of the aircraft were tied down, outside in snow, storm, rain and wind. Most pilots were laid off, only a few were kept on. I was one of the “lucky” ones. There was little or no work for pilots in the late sixties. We did not fly every day, had to do all sorts of work to keep busy like assisting the aerial photographer sorting hundreds of slides that he had taken earlier.
    The winter over, the company was getting ready again to get the Pipers ready for the banner towing season. The mechanics brought the aiircraft in the hanger, gave them a look-over, drained the tanks, changed the oil and did a run-up.
    I was assigned a photo flight, so “my” Super Cub was refueled and declared ready. I did a check of my own and, yes, that included another fuel drain. All seemed in order, so I started up and taxied to the runway.
    This particular airport had originally been intended for scheduled flights. After the war this ended, it became a base for local general aviation, but it had a 1500m paved runway.
    The take-off was normal, but when I was at about 200 ft the engine suddenly quit. I changed tanks but to no avail. There was no reaction from the tower when I made a “Mayday” call, either. I was too low for a 360, instead I sideslipped, pulled full flaps and landed on the runway where I managed to come to a stop before the end.
    I tried to start the engine again, it did not come back to life.
    I decided to pull the aircraft back to the hanger, this is not a heavy job and the photographer was assisting me. In the meantime somebody had noticed that my aircraft was no longer in the air. The mechanics drove out and took over.
    They noticed immediately that the liquid coming out of the drains was… pure water.
    The cause was: The Super Cub is a “taildragger”. The fuel is drawn from the tank, located a bit forward of the rear.
    Meaning: At rest, with the tail low, there still was a bit of water left in the tanks that did not come out when the tanks were drained.
    But when the tail of the aircraft came up during take-off, this water was able to slosh forward and be picked up in the fuel line.
    The mechanics discovered this when they raised the tail on a support in the hanger. In total they drained nearly half a litre of water.
    This has never happened neither before nor after this peculiar incident again, and I have flown a few thousands of hours on Super Cubs.
    And so I still wonder if the installation of the tanks in the wing had maybe been at a slightly wrong angle. But I will never know.

    • You aborted the takeoff run after Vr? ;-)
      Was that possible due to taking off in a small plane at a large airport?

      I wonder why this never went wrong for the Mooney pilot before, assuming he habitually did a pre-flight and habitually never sampled the fuel. If he’d usually refill the plane before hangaring it, there wouldn’t be too much air for water to condense from? and it wouldn’t condense as much if hangared? and if he refueled it before taking off, the inflow would “stir” the fuel and mix it with water? or maybe it was a shared plane, and the other pilots usually did that job?

      • Part of the issue, I suspect, is that almost empty left tank. If he’d had the tanks balanced, a lot less water would have accumulated. Also, it’s quite possible that he usually did it and skipped it that morning but didn’t want to mention it after everything went wrong. It’s a pain and, in the early morning, when there’s dew everywhere, you can get quite damp kneeling down. Of course, that’s exactly when you really should check!

  • Sometimes the simple, routine, things are what trip you up. I’m glad the guy didn’t get hurt but feel bad about that beautiful Mooney.

  • Mendel: I was wondering whether the pilot ever took sump samples; it’s possible that he had previously just done day trips or joy rides in that airplane, and had gotten home and refueled the same day, so that (as you say) moist air that came in as the tanks drained was pushed out (as they were refilled) before it could cool enough to condense. My guess is that merely refueling the next day wouldn’t have made a difference — water and gasoline are close enough to immiscible, and different enough in density (6.5#/gallon for avgas IIRC, vs 8#/gallon for water) that most of the water would have gone back to the low point in the tank very quickly — but it’s not something I’d care to experiment with. (For that matter, I’d want to sample after the refueling, just in case there was water in the tanker supplying the fuel.)

    Rudy: Wikipedia says Mooneys have “wet wing” tanks; I wouldn’t think that would allow room for misinstallation such that the drain wasn’t at the low point — but as you say, we’ll never know for sure.

    Sylvia: interesting point about the dew; I trained entirely on small Cessnas, so I always reached up to the drain rather than having to reach or even crawl under the wing. At first thought, ISTM that it would be a Good Thing for FBOs to provide creepers (low wheeled platforms found in many automobile service areas), but I can easily see a pilot neglecting to take one back to a secure location, and having it loose on the apron would be a hazard.

  • Mendel,
    I did not “abort” take-off, the engine just quit. The Piper Super Cub in question had a 150 HP engine. The take-off roll was maybe 80 metres, and if we would hold the brakes with full power before releasing them, at about 40 mph the aircraft could lift off and climb at a very steep angle (angle, not rate of climb!). I probably took it easy with a photographer and his equipment behind me, but I probably would have had more than 500 metres of hard runway ahead of me when the engine quit. The PA 18 could land in no more than 200 metres.
    Chip: I was not mentioning a Mooney, I was in a Super Cub. I do not know whether the tanks in that type of aircraft could be misaligned, resulting in water accumulating behind the pick-up lines. When parked, the PA 18 would sit in a low-tail attitude. If any water would be present, of course it would be in the rear of the tanks.
    And, as mentioned, I never really found out how it was possible for a quantity of water to accumulate that would not pass through the drains, but still in a quantity sufficient to cause engine failure after the tail would rise during take-off. I logged about 3700 hours on Cubs and Super Cubs. These aircraft had a balance tank behind the seats in the fuselage, maybe the water was in that tank. I must admit that it should have occurred to me to ask the question at some time. But I did not.
    Water accumulation was a factor in another funny occurrence:
    Many years later I was flying a Shorts SC7 Skyvan, a rather crude looking contraption. It was owned by Vincent O’Brien, a famous race horse trainer. It had a loading ramp at the back and could carry two horses. When it was not in use for the transport of race horses, it was carrying parcel post at night.
    I was on a night mail flight from Liverpool to Dublin, single pilot.
    The instruments were rather crude. It had a NAV/COM with a separate ILS indicator in front of the pilot, but that one was a bit unreliable.
    A good indicator was part of NAV/COM set 2, in the centre of the panel.
    It had a small integrated ILS, the usual two needles: one vertical for left-right deviations and the other up and down, for the glide slope.
    The horizon was the standard, no-frills basic instrument.
    The weather was poor, cloud base was given as 100 feet but the visibility was about 1000 metres. It was legal to make an approach on a “look-see” basis.
    I had to switch my scan from the artifical horizon to the ILS, in the centre panel, and back. When I was getting below 400 feet the ILS needles were starting to swing and I was glad to see the runway lights at 200 feet, even if I was annoyed with myself for being so sloppy in the last 100 feet or so.
    As I was leaving the runway an airliner on the approach asked ATC it there was any improvement. The reply was “Shorts Skyvan just landed”.
    The other pilots decided to continue their approach, a few minutes later I heard the engines at full power in the missed approach. I could not see it at all. Strange! On the apron, I noticed that my altimeter indicated more than 100 feet above airport elevation. I checked and re-checked the setting. It was correct.
    The next day the cause was revealed: The Skyvan’s static port was connected to the altimeter via a set of pipes under the pilot’s seat.
    The mechanics told me that they had drained nearly a milkbottle of water from the static system.
    I had obviously made my approach down to about 80 feet, which also explained why the ILS indications had become a bit “jumpy”.
    I had descended to below cat 2 minima without even realising it. Single pilot, in an aircraft without auropilot that was barely fit for Cat 1.
    So water can be a problem, not just in the tanks!

  • Chip,
    If you refer to my entries: I will do my best, but I must admit that there are more good and relevant comments. Probably more believable too.
    Yes, my adventures may seem a bit strange, especially in the light of the currrent state of the art of aviation and the rather loose way we operated. For instance, the same company that operated the Skyvan also owned a Piper Aztec. For some time, its transponder was unserviceable. For IFR flights within the Republic of Ireland a transponder was not yet mandatory. During the week, the Skyvan was usually parked at Dublin so for a flight to the UK (from Shannon), the pilot received an allen key.
    We would park alongside the Skyvan, using the allen key remove the transponder, and put it in the slot in the instrument panel of the Aztec. With the same in reverse on the way back.The rules have become far more stringent and are being rigidly enforced now. Anyway, the current landing fees at Dublin Airport would make it commercially not viable.
    But, believe me or not, all accounts are the absolute truth. Yes they really did happen.
    In none of those cases did I break any law; I also did my pre-flight checks. Until the incident with the Skyvan I was not aware that there was a water drain tap for the static system, accessed by removing the pilot’s seat cushion.
    Happy Easter everyone,
    keep safe!

  • Rudy — I’m not doubting any of your stories (I’ve read too many reports here and elsewhere); I didn’t follow the antecedents on your Super Cub story correctly. I do wonder how that much water could get in through the usually-tiny static port, but I wouldn’t be surprised if a small operation just hadn’t drained the system in ~forever, such that it worked until it took on a last bit of water and started distorting.

  • Chip,
    Aviation these days has become very regulated. Probably for the better. But sometimes in the days that I wrote about the rules were not always taken that seriously. And we did not have the modern electronics either, so we had a lot more leeway to behave a bit like the proverbial “cowboys”.
    Yet, there were not all that many more tragedies either, maybe even less. Certainly in the environment in which I started my aviation career, pilots were watching one another and were very quick to name and shame.
    That did not necessarily apply to bending the rules, as long as one got away with it. In such a case, it often was accepted more as a badge of honour. When it came to basic flying skills, I bet that the older generation of pilots had a good edge over the current “systems managers” that now fly aircraft. Of course, there are airline pilots who own and fly light aircraft, not rarely aerobatics, in their spare time. And I must admit that they are probably superb in every respect.
    The static system of the Skyvan (EI-BNN) was connected to the instruments via a system of tubes. Where was the static port? I don’t remember. But I DO remember the tubes under the seat. If I remember that part correctly, there probably was a drain tap there. The water more than likely was due to accumulated condensation.
    When had it been drained last before my experience in, what afterwards turned out to have been an approach to way below minima? No idea.

  • I have been a banner-towing pilot for quite a few years. At first it was full-time, later I still did it on a part time basis.
    As a funny one before Sylvia posts a new subject:
    During the winter there was not much activity. Most pilots were seaonal.I was one of the few who were kept on.
    One of our pilots got caught in a snowstorm. With visibility rapidly decreasing he managed to put the aircraft safely down in a field.
    When the worst was over, he discovered that he had landed right beside the aerodrome where he had been heading for. Better still, there was a gate nearby that could be opened for emergency access.
    What better than to open it, drag the Piper through the snow onto the aerodrome – which was a grass strip – and pretend that nothing had happened? Certainly not a “reportable incident” to the authorities!

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