With his entire family aboard, Dr. Steven DalPra found himself fighting his failing twin-engine plane as he searched for a landing strip a year ago.
One engine was gone and his landing gear was faltering, he said as he radioed for help.
"I've got single-engine problems here; mayday, mayday," he told air traffic controllers, according to data released yesterday.
Flying from another small Michigan airport to visit family in the Upper Peninsula, Dr. DalPra, a Sylvania Township anesthesiologist, was told Ironwood was the nearest spot to land.
Fourteen minutes later, he reported that the runway was in sight. But a big problem loomed: His Piper Aztec had a "complete loss of hydraulics" to the mechanism that lowered his landing gear.
He told controllers he would have to hand-pump the gear.
It was the last communication Dr. DalPra would give. The crash, seven minutes later, killed all aboard, including his wife, Colleen Morgan-DalPra, and daughters, Elizabeth, 15, Rachele, 14, and Giovanna, 12.
A preliminary report released yesterday by the National Transportation Safety Board on the Dec. 28, 2004, crash offered some clues as to why. It noted a damaged cylinder in one of the plane's engines and ice on its wings.
But it made no hard conclusions as to the crash's cause.
A toxicology report for Dr. DalPra, a flight instructor, was negative for any sort of drugs or alcohol, and there were no restrictions to visibility or precipitation. His 1977 plane had recently gone through an annual maintenance inspection on Dec. 11. Between then and the crash, it had only seen about seven hours in the air.
But an examination of the plane's left-wing engine, which had been overhauled in 1997, revealed a fractured cylinder, which had marks "consistent with fatigue cracking," suggesting the cylinder may have been giving out over some time. That same engine supplied hydraulic pressure to the landing gear, without which it would have had to be hand-pumped.
The landing gear was found down at the time of the crash.
Dave Kurtz, a flight instructor for Toledo Suburban Airport, remembers being in a Piper airplane when one of its cylinders gave out.
"It started running very rough. We had to shut it down. It was leaking oil like a big bug bomber," he said. "Then, if you've lost an engine, you're relying on your rudder quite a bit for directional control."
Much like a boat, Mr. Kurtz said, if a plane goes too slow, the rudder becomes increasingly useless, and the thrust from the one good engine could tip the plane over.
As for trying to hand-pump a plane's landing gear, he said it can be difficult.
"It can be distracting, you have to lean over for it, it's hard to deal with other things like instrumentation and icing. It's a situation I wouldn't want to be in," Mr. Kurtz said.
Investigators also found ice on the leading edges of the wings, which can reduce the wings' ability to lift the plane. But Mr. Kurtz noted the report was not specific as to how much ice was on the wings.
One point of debate on the report was whether the propeller had been "feathered," meaning the blades had been turned sideways so as to knife into the wind and thus reduce air friction.
"If the propeller hadn't been feathered, it makes the plane much harder to control. It would be like trying to paddle a canoe with somebody holding a paddle out flat to the direction of travel," Mr. Kurtz said.
Dr. DalPra said minutes before crashing he had a "single engine and one propeller feathered," but the report cited a manufacturer who said that wouldn't have been the case had the propeller been feathered at the time of impact because a large quantity of oil had drained from the engine's propeller hub.
The engine was manufactured by Pennsylvania-based Lycoming Engines, though the propeller assemblies were built by Hartzell Propeller Inc. of Piqua, Ohio A third company, Texas-based Engine Components Inc., overhauled the cylinder that was found shattered.
Mr. Kurtz noted that spotty low-altitude radar in the area made it hard to tell exactly what happened. NTSA officials said as a matter of policy they do not comment on their reports. The report's investigator in-charge, Tim Sorenson, was on leave yesterday and couldn't be reached.
A final report on the crash is expected by early February.
Contact Tad Vezner at: