Pilot Debrief

AERO VODOCHODY L39C near West Milford, NJ — 2011-07-09

Final reportERA11LA390
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Date
2011-07-09
Location
West Milford, NJ, USA
Airport
4N1
Aircraft
AERO VODOCHODY L39C
Registration
N111XN
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Landing

Probable cause

The pilot's excessive airspeed and failure to attain the proper landing point, which resulted in the airplane touching down too fast and too far down the short runway. Contributing to the accident was the pilot's failure to retract the flaps after landing, which resulted in delayed brake activation, the pilot’s decision to land on a runway with an insufficient safety margin for the landing conditions, and the pilot’s failure to use the emergency brake lever.

Contributing factors

Contributing to the accident was the pilot's failure to retract the flaps after landing, which resulted in delayed brake activation, the pilot’s decision to land on a runway with an insufficient safety margin for the landing conditions, and the pilot’s failure to use the emergency brake lever.

NTSB narrative

While landing on runway 24 at an airport that had obstructions on both ends of the runway, had only 3,471 feet of usable runway available, and which required a 3.50 degree glideslope for landing, the pilot of the ex-military jet trainer landed the airplane and overran the runway. According to the pilot's written statement, during the landing he touched down 5 to 6 feet prior to the painted "24" on the runway. He then lowered the nose of the airplane and "retracted" the wing flaps. He then pushed the control stick forward and applied the brakes by squeezing the control-stick-mounted brake handle, but braking did not occur. He then applied the brakes a second time, extended the speed brakes, wiggled the control stick, and pushed the control stick forward and applied the brakes a third time without result before applying them a fourth time. He then felt the anti-skid engage. The airplane then struck a chain link fence and went over an embankment before impacting the ground, nosing over, and coming to rest inverted. The pilot was seriously injured during the impact sequence and the airplane incurred substantial damage to the forward fuselage. Review of the pilot's statement also revealed that he had not touched down at 96 knots indicated airspeed, as specified by the landing speeds chart, but had touched down at 106 knots, which would have extended his landing distance by about 20 percent. Further, witnesses observed the airplane actually touch down about 300 to 400 feet past the painted "24" on the runway, not the 5 to 6 feet prior to the painted "24" as stated by the pilot. Skid marks that matched the width of the airplane's main landing gear geometry were also present on the runway surface. The marks started about 1,270 feet past the painted "24" on the runway and continued until they left the pavement. Review of performance planning charts also revealed that the safety margin for operating at the airport was insufficient: even if the airplane had touched down just prior to the painted "24" on the runway, the pilot would already have 205 feet of the usable runway behind him, and with moderate braking the landing roll would have been about 2,500 feet, and the landing distance, when landing over a 50 foot obstacle, would have been about 3,370 feet. With intensive braking, the landing roll would have been about 2,000 feet, and the landing distance, when landing over a 50 foot obstacle, would have been about 2,900 feet. The pilot also would not have met the accelerate/stop criteria for takeoff or a balked landing, as the airplane required 3,600 feet to accelerate to takeoff speed and then stop after an aborted takeoff. Examination of the airplane did not reveal any evidence of a preimpact mechanical failure or malfunction that would have resulted in failure of the normal braking system. The flaps were also in the 44 degree (landing) position and had not been retracted, as was required for a minimum run landing to reduce lift, increase weight on the wheels, and reduce tire skidding. Examination of the flight manual also revealed that, in the event of a brake failure, activation of the main wheel brake units still would have been possible if the pilot had operated the emergency brake lever. According to the flight manual, he should have used the emergency brake lever if he believed that he had lost normal braking.

Analysis

Primary failure mode
Controlled flight into terrain
First missed decision gate
Pilot should have used emergency brakes after first brake failure.

NTSB coding

Evidence available

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  • 23 docket documents
View NTSB final reportView NTSB docket

Docket documents23

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