According to the pilot, he purchased the multiengine airplane about three months before the accident, then flew it uneventfully to another airport for an annual inspection and to have other maintenance issues addressed.
After the annual inspection was completed, several engine-runs and taxi checks were performed with no anomalies noted.
On the day of the accident, the pilot completed a preflight inspection of the Piper PA-30 and intended to fly to his home airport.
The mechanic that completed the annual inspection told him that he had drained black sooty water from the fuel tanks. The pilot went out to the airplane and drained water out of the tanks until the fuel was clean and clear.
About five to six minutes into the flight, the left engine began to run rough and lost partial power. When the pilot increased the power on the right engine, the right engine immediately lost all power.
He set up for an off-airport landing and noticed a highway near Milan, Georgia, so he lined up with the centerline of the highway and landed.
During the landing rollout, the right-wing tip hit a highway sign. The airplane subsequently rolled off the highway and came to rest upright in a field.
Post-accident examination of the airplane revealed substantial damage to the right-wing spar.
Two days after the accident, more water was sumped from both fuel tanks. After the water was removed, both engines ran normally.
The pilot told investigators that there were no pre-impact mechanical malfunctions with the airplane.
Based on this information, it is most likely that the loss of engine power the pilot experienced during the accident flight was due to fuel contamination.
Probable Cause: The pilot’s inadequate preflight inspection, which resulted in a total loss of engine power during cruise flight due to fuel contamination.
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This October 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.
I feel bad for this unfortunate man as he probably has only limited knowledge of the fuel system of the PA30. The mechanic is the one who should have realized that this aircraft definitely has some fuel problems and needed to look a lot further into the problem. I personally love the twin Comanche but because of its age they can be high maintenance!
It doesn’t state clearly, but sounds like the aircraft was purchased after sitting a long time..That would explain part of it.. any long term parked aircraft should have a major checklist going thru!
Comanche fuel tank cells shouldn’t ‘collapse’ …but if they do (d/t being empty)…wrinkles can form that will trap water that’s not going to “drain” during a normal preflight.
I’d expect the pilot and A&P to know this?
In 2012, the ICS (International Comanche Society) published a great book of “tips” collected from their Comanche FLYER magazine (from Feb 1973-Sep 2012). In it, there’s a whole chapter on Comanche fuel system issues, including contamination problems.
That is something I tried to look up, because I suspected a fuel cell/bladder problem. But couldn’t find anything on it.
And as someone has indicated, and I am puzzled about it, why didn’t the I/A Note this issue. They should have certainly inspected the fuel tanks as part of the inspection and so should have noted this problem to the owner as something needing repair, or some kind of maintenance (never having dealt with this, I have no clue what has to be done).
You can find this info at the following site:
https://www.comancheflyers.com/publication/view/comanche-tips-3-fuel-system/#page31
I am questioning annual inspections and who is fueling this aircraft.
Perhaps fuel tank cap gaskets are the culprit.
Is the fuel tank vent system lost it’s integrity? Was anything different in the fuel filters and dispenser ?
I am sure the insurance company wants to talk about this.
I did a Google search for ‘black sooty water’ – “The most common cause of black particles in tap water is the disintegration of rubber materials used in plumbing fixtures. These particles float and often adhere to sinks and bathtubs and can appear sooty or greasy.” Seems to fit the pilot’s summary afterwards that he suspected bladder deterioration. I didn’t find any warnings for black sooty water in the fuel system section of the POH.
What accounts for all that water entering the fuel tanks ? Why was it so cruddy? How come all the water wasn’t evacuated on the first sump draining? Are those tanks designed so water can hide itself in the cracks and crevices to work its way down to the bottom during flight? Seems to me from reading this account that the pilot and mechanic acted pro-actively and prudently to check the fuel situation. What the Hades went wrong with this scenario? Was the gas cap left loose or off before the purchase? What kind of crud was it? Tree foliage? Another fine example is tne annals of GA where no matter how hard you try, ‘if the ‘skeeters don’t get you, the ‘gators will’ as they say in south Florida. Just plain pathetic.
Regards/J