Reason for engine’s failure a mystery

Federal investigators have determined that a failed engine likely caused a pilot to lose control of his plane and crash west of Cody last year. However, after months of investigation, the National Transportation Safety Board (NTSB) was unable to figure out why the left engine of the rented Cessna T310R stopped working.

Four people — pilot Don Scott, his friend Joyce Bartoo of Washington, D.C., his sister Diane J. Stubbs and her husband Gerald B. Stubbs of Maryland — all died in the July 18, 2015, crash.

Scott was a 66-year-old Denver attorney with some 570 hours of prior flying experience. He’d taken the group for an unplanned detour over Yellowstone National Park as they flew from Sheridan to Billings.

After circling Yellowstone, Scott got permission from air traffic control to continue toward Billings; the air traffic controller directed Scott to climb from 13,300 to 15,000 feet shortly before noon.

Several minutes later, air controllers lost contact with Scott and the plane, which turned southeast toward Cody and began plummeting.

In what the NTSB described as an apparent “near-vertical” dive, the Cessna crashed into a wooded area west of the Mooncrest Ranch and roughly 10 miles northwest of the Buffalo Bill Reservoir.

The airplane was smashed into pieces and caught on fire.

“It is likely that the left engine was not operating at the time of impact,” the NTSB wrote in its final April 14 report on the accident, adding, “The pilot likely lost control of the airplane following the loss of left engine power.”

The NTSB did not reach a conclusion about what caused the engine to stop working.

At the time Scott was directed to climb to 15,000 feet, there was an active weather advisory — called an AIRMET — that icing could occur between 14,000 and 22,000 feet.

“The (air traffic) controller did not provide this information to the pilot, and it could not be determined if the pilot was aware of the AIRMET,” the NTSB wrote in its report. The report adds that, “although the airplane was operating in an area conducive to aircraft icing, the reason for the loss of engine power could not be determined during post-accident examinations.”