NTSB Identification: SEA01LA169.
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Accident occurred Saturday, September 08, 2001 in Pasco, WA
Probable Cause Approval Date: 06/18/2002
Aircraft: Cessna 172N, registration: N426SK
Injuries: 1 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The accident aircraft, piloted by a solo student, was attempting to taxi onto runway 30 for takeoff behind a Horizon Air DHC-8 undergoing a maintenance engine run in a runup area on the northeast side of the approach end of runway 30. The student pilot stated that after completing his preflight checklist, he waited, believing that the DHC-8 was about to take the runway for departure, but that when this did not happen he requested and received takeoff clearance for runway 30. The tower controller did not issue any cautionary advisories for the DHC-8 activity to the student pilot with the takeoff clearance. The student pilot reported that after starting toward the runway, "I was more than half way past behind [sic] the Horizon plane, when they revved their engines." The propeller blast from the DHC-8 forced the accident aircraft to tip to the left and forward, causing it to strike its wingtip and propeller on the taxiway surface. The aircraft continued to be buffeted by the propeller blast of the DHC-8 for several more minutes as the DHC-8 continued to do its engine run. The tower was subsequently unable to reach the DHC-8 on the radio. The DHC-8 crew, a pair of Horizon Air mechanics, continued its engine run until it was approached and signaled by an airport operations vehicle dispatched to the scene by the tower. About this time, the tower re-established radio contact with the DHC-8 and instructed the DHC-8 crew to reduce engine power. In interviews with an FAA inspector, the Horizon Air mechanics indicated they did not know how or why they lost radio contact with the tower. FAA Order 7110.65N, "Air Traffic Control", instructs controllers to "Issue [wake turbulence] cautionary information [to include use of the words jet blast, propwash, or rotorwash] to any aircraft [including those on the airport movement area] if in your opinion, wake turbulence may have an adverse effect on it." However, Order 7110.65N further states that "Because wake turbulence is unpredictable, the controller is not responsible for anticipating its existence or effect." A review of FAA Air Traffic Bulletins found no information on jet blast/prop blast hazards.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The DHC-8 maintenance crew's failure to maintain radio contact with the tower during its engine run. Factors included the tower controller not issuing a safety advisory on the DHC-8 engine run to the accident pilot as recommended by FAA guidance, and the FAA's failure to make information on jet blast/prop blast hazards available to controllers. Full narrative available
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