The flight instructor reported that while he and the student pilot were on a taxiway in Anchorage, Alaska, under air traffic control (ATC) instruction, the Cessna 172 encountered prop wash, originating from a larger, four engine turbine-powered airplane performing a maintenance engines run-up.
The maintenance run-up was performed in a location adjacent to the active taxiway that was authorized for parking as well as 80% engine power run-ups.
The larger turbine-powered airplane was the third in a row a five of like model airplanes being parked at the location.
The Cessna 172 was not on frequency when the larger turbine-powered airplane was given the clearance, and was not told by ATC at any time during their taxi of the larger turbine-powered airplane’s intentions.
Subsequently, the 172 was blown approximately 80′ from its original location while taxing behind the larger turbine-powered airplane, which resulted in substantial damage to the firewall.
The flight instructor reported that there were no pre impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.
As a safety recommendation the flight instructor stated that the incident could have been prevented with better communications between the tower controllers and the larger turbine-powered airplane’s ground personnel.
Probable cause: The facility’s designation of the taxiway for use by maintenance personnel to conduct high thrust tests without appropriate safeguards in place, which led to maintenance personnel conducting high-power, run-up thrust procedures across the active taxiway and resulted in the loss of directional control of a Cessna 172 on the taxiway when it encountered a sudden, unexpected blast of engine thrust.
NTSB Identification: GAA16CA442
This August 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
I got my early pilot training on an Air Force base via the Aero Club. The military always has their red beacons on when the engines are running as an indicator to anybody in the vicinity. We had a strict policy that you NEVER taxied behind any of the military aircraft when the red beacon was on, or showed other indications that the engine(s) were running. I once spent about 15 minutes sitting in a C150 with my instructor waiting for an F-4 to shut down that was getting maintenance. The ground crew did motion for us to proceed as the aircraft was at idle but we refused, better to waste 15 minutes with the Hobbs running than be responsible for a bent bird and no, there were no other paths we could have taken to get to the runway. Although I have only flown GA type aircraft I follow the practice of having the red beacon on when the engine is running or about to start as well as to never taxiing behind any aircraft of sizable power when it is running.. Just one of the many valuable lessons that my instructor (an F-4 pilot) drilled into me.
I have seen Customs at BKL require a jet to pull into the apron area with small piston aircraft while having to keep their engines running. A C152 looked like a tethered kite behind that jet. It was at full extension on the tiedown ropes with the wheels off the ground between bounces.
The Jet’s pilot had the what can I do attitude. Customs told me to park here like this.