A Lockheed P-2E Neptune aircraft, modified into firefighting aircraft, was operating a firefighting mission out of Broomfield-Rocky Mountain Metropolitan Airport (Colorado, USA) on this day in aviation history, 2010. On board the aircraft a crew of two.
The aircraft in its final position (Source & © NTSB)
As the aircraft returned from a fire retardent drop to Broomfield and was approaching the airport the crew observed the main hydraulic system had failed. An emergency was declared and the aircraft was configured for landing using the emergency systems.
After landing on runway 29R the pilot opted to vacate the runway via a high speed exit that would lead to the tanker base ramp. When attempting to slow down the aircraft using the emergency brakes there was no response from the brakes. The aircraft crossed the tankerbase ramp, left the paved ramp, went through the airport perimeter fence, went down an embankment, and came to a stop on a road.
A post accident investigation revealed extensive damage to the aircraft;
Nose landing gear failed backwards and upwards
Nosewheel well and aircraft lower structure damaged
Plexiglass nose broken
One propellor blade bent on right hand engine
All four propellor blades broken approximately mid-span on the left-hand engine
Fire damage on the left engine nacelle
Further investigation of the aircraft showed there was a rupture in a hydraulic line in the main hydraulic system.
The aircraft after recovery, note the fire damage to the engine cowling (Source & © NTSB)
The cause of the failure of the emergency brakes system was caused by crew error. When the normal hydraulic system failed while returning to the airport, the pilot briefed the copilot about the proper procedures to lower the gear. The co-pilot referred to the emergency procedures checklist and went to the spar area to operate the emergency gear extension systems. The nose gear down select was activated and the gear dropped. The co-pilot then pinned the gear in the down position and moved the emergency nose gear extension system selector to the “bypass” position, which cut off emergency system hydraulic system pressure to the elevator flight control and emergency brakes. The airplane flight manual specifies the selector be placed back to the “normal” position. The co-pilot then made an unsuccessful try to lower the main gear by releasing the up-lock lever, but on the second try the gear came down. The pilot noticed all three landing gear indicators showed the gear was safely down and locked and reported this to the tower.
The investigation report by the National Transportation Safety Board into the accident was published on the 28th of June 2012. It is available by clicking here.
The aircraft after recovery, note the fire damage to the engine cowling (Source: www.skippyscage.com © Paul Filmer)