TULSA, Okla. (AP) - Investigators have examined a heater that the sole survivor of a plane crash that killed four people connected to Oral Roberts University described as having a "terrible" odor when turned on.
The plane had left Tulsa's Jones Riverside Airport and was en route to a Christian youth rally in Council Bluffs, Iowa, when it crashed May 11, 2012, near Chanute, Kan.
Pilot Luke Sheets, 23, of Ephraim, Wis., was killed along with three passengers: Garrett Coble, 29, of Tulsa; Stephen Luth, 22, of Muscatine, Iowa; and Austin Anderson, 27, of Ringwood.
The Tulsa World reported survivor Hannah Luce told the National Transportation Safety Board that the heater had a "terrible smell." She also recalled seeing "dark, black smoke" enter the plane when the heater was turned off, which she said made it difficult to see.
Water was poured into the heater vents, according to the NTSB's factual report. The pilot tried to pull up during an attempted emergency landing, but the tip of one of the wings hit the ground first, the report says.
Craig Sheets, father of the pilot, has said he believes the plane's heater malfunctioned and that his son made a "heroic effort" to land safely. The elder Sheets, a retired commercial pilot, also served as an Air Force pilot during the Vietnam War.
The report also says a certificated flight instructor told investigators that during a flight on April 25, 2012, the heater's overheat light illuminated shortly after the heater was activated. The heater shut down and no smoke or fumes were detected by the flight crew, so the flight continued to its destination, according to the report.
The document also mentions a Feb. 9, 2011, work order that described work done on the heater. "Troubleshoot cabin heater ... Found stuck airflow switch, cleaned and heater operated normally," the work order read.
The NTSB report says "no pre-impact anomalies were detected" with either of the plane's engines.
A probable cause report on the crash has not yet been issued.