Accident Overview
On June 26, 2010, about 1300 mountain daylight time, a Lockheed P2V-5 airplane, registration N1386C, sustained substantial damage during a landing roll overrun at Rocky Mountain Metropolitan Airport (BJC) in Broomfield, Colorado. The pilot and co-pilot were not injured. The airplane was registered to Neptune Aviation Services Inc., of Missoula, Montana, and operated by the United States Department of Agriculture (USDA) Forestry Service under an exclusive public-use firefighting contract. Visual meteorological conditions prevailed, and a company flight plan was filed for the fire suppression flight, which originated from BJC at 1150.
Sequence of Events
According to the pilot, after a “normal” retardant drop, the main hydraulic system failed. The airplane was configured for landing using emergency hydraulic pressure, and an emergency was declared. The pilot reported that the landing was routine; however, when he attempted to stop the airplane using the emergency system brakes, there was no response. The airplane went through a fence, down an embankment, and came to rest nose down on a city street. The pilot and co-pilot exited unassisted through the airplane’s upper hatches.
The airplane had landed on runway 29R. The pilot exited the runway via taxiway A13. The airplane proceeded across taxiway A, through a grassy area between taxiway A and the tanker base ramp, and across the northwest portion of the tanker base ramp. It then went off the prepared surface through the airport perimeter fence, down the embankment, and came to rest on the north side of Network Parkway. Pieces of the perimeter fence were found in the parking lot of an adjacent office complex; one piece went through an office window.
Emergency Procedures and Co-pilot Actions
The USDA Forest Service reported that while returning to the airport, the pilot briefed the co-pilot about 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 pilot briefed the tower that they would not have nose wheel steering but would try to take the high-speed taxiway (A-13) off the runway near the tanker base. They received clearance to land and to make a right turn when able to exit the runway. After touchdown, the airplane was slowed using reverse thrust on the propellers and steered using differential braking. A hydraulic accumulator supplies enough pressure to the brakes for a few applications in the event of a loss of system pressure. The pilot felt he had adequate directional control and could make the right turn at A13 using the remaining emergency braking system to stop the airplane in the dirt prior to the tanker base ramp. The pilot made the turn off the runway and taxied toward the ramp. As they approached the end of the taxiway, the pilot applied the emergency brake with no result. He checked to see that he had the right lever and reapplied, again with no result. He then told the co-pilot they had no brakes and were going to wreck.
According to the airplane flight manual, the procedure for hydraulic failure is to land and stop on the runway using the emergency brake and accumulator pressure. After stopping, the stiff-knee pins are to be installed, and the airplane is to be towed to parking.
Examination Findings
A postaccident examination of the airplane showed the nose gear broken aft and upward, with crushing and bending of bulkheads and walls in the nosewheel well and underside of the nose structure. The Plexiglas nose dome window was broken out. One of the four propeller blades on the right engine was bent aft. All four propeller blades on the left engine were broken off near mid-span. There was also fire damage observed to the outer side of the left engine nacelle just behind the ring cowling. Further examination of the airplane’s hydraulic system showed a rupture in the line from the main hydraulic and tank system. No other systems anomalies were found.