According to the pilot, the accident occurred during the Cessna 172’s first flight of the day.
The airplane was stored outdoors for several weeks prior to the accident flight.
During the pilot’s preflight inspection, he observed water in the fuel tanks. He reported that he took a fuel sample from the left wing fuel tank, because he could see water in the tank through the filler port. He extracted about one ounce of water from the left tank and concluded that “there wasn’t that much water in the fuel system.”
The pilot told investigators that the airplane was fueled several weeks prior to the accident.
He confirmed that the left wing fuel tank contained two gallons of 100LL and the right wing fuel tank contained 16 gallons of 100LL before starting the engine.
He started the engine with the fuel selector in the BOTH tank position and ran the engine about two minutes, before he contacted the ground controller at Whiteman Airport (KWHP) in Los Angeles.
He contacted the tower controller a few minutes later to report holding short of Runway 12 for departure.
The pilot recalled that the flaps were set to 0° and the mixture was rich, but he could not recall if the airplane had a trim wheel.
After the 172 was cleared for takeoff from Runway 12, the pilot taxied onto the active runway and applied full power initiating the takeoff roll.
During the initial climb, at about 200 feet, the engine lost power. He attempted to restart the engine by turning the ignition key to engage the starter, but the engine did not restart.
He transmitted a May Day call to the tower controller and initiated a turn to the right. A minute later the plane hit the ground and came to rest on an active railroad crossing. Moments later, bystanders got the pilot out of the airplane just before it was struck by a Metrolink passenger train.
The pilot was seriously injured in the crash.
Climatological observation records from the National Oceanic and Atmospheric Administration (NOAA) revealed that during the weeks leading up to the accident, rain was observed in and around KWHP. The observation indicated that the presence of rain was detected a total of 18 days while the airplane was stored outdoors.
Post-accident examination revealed that the right wing tank fuel cap was present, but missing the silicone vent. The right fuel cap rubber gasket was hard to the touch, brittle, and portions of the outer gasket had deteriorated and were missing.
The left wing tank fuel cap was present, but the rubber gasket was hard to the touch, brittle, and portions of the outer gasket had deteriorated and were missing.
Continuity of the fuel system was observed from the left and right wing fuel tank inboard fuel pickups, through the fuel selector and gascolator using compressed air to verify volumetric flow.
The gascolator was disassembled and revealed about 1 teaspoon of a white, granulated, corrosion substance. Internally, the gascolater bowl was pitted, and the filter screen revealed a vivid line of corrosion emanating from the top left to the bottom right, consistent with the airplane’s post-impact resting position. The presence of rust and the corroded substance were observed throughout the gascolator.
The carburetor was disassembled and about ½ teaspoon of the corroded substance was extracted from the fuel inlet screen. Rust, and the corroded substance were observed throughout the carburetor.
Probable Cause: The pilot’s inadequate preflight inspection during which he failed to remove all water contamination in the fuel system, which resulted in a total loss of engine power on takeoff. Contributing to the accident was the condition of the fuel caps, which allowed the water to enter the fuel system.
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This January 2022 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
It sounds like this C172 is tied down outside. That’s not bad unto itself, but certain extra attention in maintenance practices is required. It also seems that either this aircraft doesn’t fly often. Here again, certain things just can’t be put off until the annual inspection! The fuel cap gaskets need to be replaced at any time they no longer seem pliable, and/or you can’t leave a thumbnail impression in the rubber. DO NOT wait until they are cracked or brittle! Also, if you can turn the fuel caps easily, the gaskets have taken “a set” and won’t seal properly. The condition of the fuel caps themselves is paramount, too.
When you sump the tanks with the sampler cup, don’t just drain and dump a few samples. Look at the sample and see if there is water! Same thing applies for when pulling the gascolator drain handle. Use the cup and visually check the fuel sample.
For an “outside” aircraft, disassembling, inspecting the gascolator annually may not be enough. The maintenance manual calls for this at 100 hour inspections and at annual inspections. My bet is this hadn’t been done for a very long time. This applies to pulling the carburetor drain plug as well!
One thing that gets overlooked too is the fuel selector sump drain plug on the aircraft belly. I have worked on a number of older C172’s where the plug’s factory safety wire was still in place! What I used to do was remove that plug and install a brass Curtis drain plug. This serves as an additional sump drain that can be sampled on preflight.
Per the 6120 form, the aircraft was flown only 9,6 hours since the last annual…
so, parked outside, collecting water in the tanks, gascolator and carb.
He obviously never sumped the gascollator, or he would have seen the corrosion products in the sampler. [ it is a bit difficult, having to kneel and look under the cowl opening.!]
Wow.!! there’s more here than just water in the fuel.
– The amount of aluminum corrosion products in the gas collator and carb, indicate a long time with water in the gas collator, maybe years, to get that much ‘stuff’.
– finding the corrosion ‘stuff’ in the carb, indicates that it was flown a number of times in this condition.
– Poor maint. by an A&P , allowing the fuel caps to degrade, allowing water in the tanks.
no check of the gas collator or carb for contaminates.
[ My Cessna has a glass bowl, so easy to see ‘stuff’, but I sump it every flight. I also flush the carb bowl at the annual to remove any ‘stuff’ there].
– no mention of sumping the right tank or gas collator.
BTW, his medical was expired.
Yes, the C172s have a trim wheel, and most are ‘key start’….My 1961 C175 does not.!
and, yet another good reason to hangar an aircraft…
it brings to mind the song.. ‘but don’t you know, it never rains in southern california.’…
“pilot”…cant recall if the plane had a trim wheel, turned the key to start…really???