The pilot reported that he was hired to perform a pre-buy inspection of the Piper PA-28, then fly it to New Jersey to the new owner.
He and his friend arrived in Florida a few days before the accident and he performed the pre-buy inspection.
He noted that the cylinders had been replaced and was told by the seller that the break-in for the new cylinders was not completed.
The pilot further stated that he “knew that it was going to be a risky flight home,” but decided to proceed.
On the day of the accident, he took off and circled Melbourne Orlando International Airport (KMLB) several times and climbed the airplane to 7,000 feet mean sea level.
He stated that everything looked and ran well, so he decided to proceed to New Jersey.
About 20 miles northwest of KMLB, he noticed that the engine was running rough and the oil pressure was low.
He notified air traffic control and turned back to KMLB.
The roughness increased and the engine started vibrating, so he reduced the power to 1,500 rpm. The engine continued to run rough, so he shut the engine down and thought he could glide to Runway 9R at KMLB.
Once he realized that the airplane would not make the runway, he maneuvered for landing in a parking lot. The pilot, who was injured in the crash, could not recall much after that point, but thought that the airplane may have collided with a telephone pole.
According to an FAA inspector, the airplane hit telephone wires and came to rest inverted in a parking lot. Both wings sustained substantial damage.
Examination of the engine revealed that the crankshaft would rotate approximately 90° before it came to a hard stop with a metal “clunk” sound.
Cylinder Nos. 2 and 3 were removed for an internal examination of the engine, which revealed fractured connecting rods on each cylinder. The No. 2 connecting rod was found fractured with its bottom cap heavily damaged and flat in shape, laying below the engine crankshaft along with its corresponding bearings.
The No. 3 connecting rod was found fractured similar to the No. 2, but both the connecting rod end and crankshaft journal exhibited a dark color, and remnants of its bearing were dark and smeared on the connecting rod end and cap.
The No. 3 crankshaft journal was found pitted and displayed coloration consistent with presence of corrosion and smeared bearing material.
Probable Cause: A loss of engine power due to oil starvation as a result of the failure of the No. 3 crankshaft journal bearing.
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This March 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 would certainly appear that bearing movement is the culprit here, at least on the surface. The engine log entries indicate the engine had 2762.04 TT but 54.04 SMOH when the first cylinder was replaced in 2020. Then, at 54.99 SMOH a year later, the remaining cylinders were replaced, probably as a condition of sale.
The O-320-B2B narrow deck engine originally used a doweled front main bearing and thin-wall high-crush bearings for the other journals, thus, no dowels. If the bearing spun, it would have been one of them. (The front main bearing can’t spin unless the dowels shear and the engine will lock tight if improperly assembled).
But what’s bothersome here is that crankcase fretting is the main cause for bearing release. Cylinder replacement without tension plates only makes it worse. It’s common on high time engines, not those with so few hours since overhaul. There is no obligation to overhaul the crankcase during this time, bit the overhauler is expected to measure bearing bores and perform other inspections before deciding whether or not overhaul of the case is warranted. There is more to this story somewhere because if the oil pump was clean and without scoring from debris, a lot happened within 20 miles of KMLB.
Aviation expert Mike Busch always reminds us all to proceed with caution removing cylinder(s) . Obviously a spun bearing and the A&P ? that did the job owns this one….
spun main bearing causing oil passages to be blocked most common reason for this…
I agree that a main bearing spun, most likely due to the crank being moved, while replacing multiple cylinders without using a torque plate to maintain tension on the thru-studs.
Also, the pilot flying the aircraft should have spent the time to break in the cylinders by orbiting near the airport, which would take a few hours.
The failure would have then occurred within gliding distance of the airport.
I sure hope that the seller now owns the wreck.?