ABOVE: File images from the December 2011 plane crash near Silverton.
A rapid change in the weather over Silverton early on the afternoon of Dec. 3, 2011 likely contributed to the crash of a small passenger plane that left four Durango residents dead, according to a report released this week by the National Transportation Safety Board.
And the NTSB said the pilot of the doomed plane pleaded for help from an air traffic controller moments before the plane disappeared from radar and contact was lost.
A factual report issued March 20 by the NTSB noted that the plane left Animas Air Park in Durango at 1:19 p.m., without filing a flight plan.
The NTSB stated that “instrument meteorological conditions” prevailed at the time, but the pilot, Steve Osborne, 59, was not instrument rated.
According to a weather study conducted by an NTSB meteorologist, at noon on Dec. 3 cloud tops in the San Juans were at about 13,000 feet but by 2 p,m., a low pressure system and a surface trough had pushed clouds as high as 22,000 feet.
The plane crashed at about 1:35 p.m., in Soda Gulch just north of Silverton. Small bits of debris rained down on County Road 110 north of town and the crash left a debris field 200 feet wide and 1,200 feet long.
The wreckage was recovered last spring and reassembled in a hangar in Greeley.
The NTSB reported the pilot contacted air traffic control in Denver, stating he was 12 miles southeast of Telluride, approximately over Silverton, at an altitude of about 20,000 feet.
“The pilot requested visual flight rules flight following to (Aspen airport) and reported that he could not descend below his altitude and maintain visual flight rules,” the NTSB report stated.
The NTSB report detailed the conversation:
The pilot requested a flight following, in which controllers would provide navigational assistance.
“Denver Center reminded the pilot that in order to fly VFR that he needed to be below the flight levels (below 18,000 feet). The pilot reported that he would descend below the flight levels as soon as he could. Denver Center asked the pilot if he could maintain VFR below his current altitude, and the pilot responded that he could not.”
The air traffic controller then asked Osborne if he was capable of instrument-only flight.
“I’m capable. I’m studying it at this time, but if you could help me head on over, I’d sure appreciate it,” Osborne responded, according to the NTSB.
The NTSB said Denver Center again asked the pilot if he was capable and qualified for instrument flight, and the pilot replied that he was not qualified.
“That was the last radio communication from the pilot,” the NTSB report states.
Moments later, the airplane disappeared from radar and contact with the pilot was lost.
The NTSB noted that witnesses in the Silverton area heard the plane overhead but did not see it through the clouds, and that it sounded as if it were doing aerobatics or changing altitude quickly.
The report released by the NTSB last week is not the final verdict on the matter. The NTSB’s final report is still pending and is likely to be released within the next six months.
While the report did not list an exact cause of the crash, it pointed to the weather conditions and noted studies showing that “a pilot who has not been trained in attitude instrument flying, or whose instrument skills have eroded, will lose control of the airplane in about 10 minutes once forced to rely solely on instrument reference.”
The report noted that Osborne had 593 hours of flight time, including 217 hours in the plane that crashed, a Socata TB21 four passenger, single-prop aircraft. But Osborne lacked instrument training.
The NTSB said that “if the natural horizon were to suddenly disappear, the untrained instrument pilot would be subject to vertigo, spatial disorientation, and inevitable control loss.”
The NTSB pointed out that it recommended in 2005 that private pilots be required to demonstrate basic ability with instrument control in the biennual flight reviews, but that recommendation has not been implemented.
Also killed in the Dec. 3, 2011 crash were Jan (Measles) Osborne, 50, Tyler Black, 24, and Gena Rych, 27. They were enroute from Durango to Aspen to attend a party for Alpine Bank.