Investigation Summary
The flight was operating in weather conditions that deteriorated rapidly while the aircraft was in a holding pattern. Although the U.S. Weather Bureau office at the airport recorded visibility dropping to near zero, this information was not relayed to the tower controllers, who continued to report visibility of one mile to inbound crews. Flight 512 was cleared for an ILS approach to Runway 4R, despite the precision approach radar being out of service. The crew maintained visual reference until very late in the approach, descending to approximately 25 feet above the ground and 1,000 feet past the touchdown point before losing visual cues in a thick fog bank. As they attempted to transition back to instrument references for a go-around, they retracted the flaps to 20 degrees. Aerodynamic analysis indicated that a 9 degree nose-up attitude was required to maintain level flight with flaps at 20 degrees at their current speed, yet the crew only achieved a 3 to 5 degree pitch. Without a corresponding increase in engine power to compensate for the configuration change and low pitch, the aircraft settled into the marshy terrain.
Final Conclusions
The Civil Aeronautics Board (CAB) determined the probable cause was the technique employed by the crew during the abandonment of the approach under fog conditions that had not been adequately reported. Specifically, the crew failed to arrest the aircraft's descent because they did not apply sufficient power or rotate the aircraft to a sufficient nose-up attitude during the flap retraction phase of the go-around.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Killed in crash.
First Officer
Killed in crash.
Flight Engineer
Killed in crash. Had 149 hours as a flight engineer and 718 as a pilot on the DC-7.
Systems & Failure Modes
Flaps
The crew retracted flaps from 40 degrees to 20 degrees during the go-around, which significantly reduced lift and required a higher pitch angle or more power to maintain altitude.
Runway Visual Range (RVR) Instruments
The airport's visibility measuring equipment recorded a drop to zero visibility just before the units themselves failed, preventing the tower from receiving accurate weather data.
Interesting Facts
- 01The precision approach radar (PAR) at Idlewild was out of service at the time of the accident.
- 02Visibility instruments at the Weather Bureau office had failed shortly after recording near-zero visibility, but this was not communicated to the tower.
- 03Initial ground contact occurred 3,460 feet from the runway threshold when the propellers of engines 1 and 2 struck the terrain.
- 04The aircraft's catastrophic breakup occurred 3,600 feet from the threshold when the fuselage and wings struck a 3-foot high mound of earth.
- 05All 26 survivors were seated in the rear half of the aircraft, which remained relatively intact.
- 06The Captain, Edward Bechtold, was the chairman of the New York Air Safety Committee.
Safety Actions & Advisories
Weather Reporting Improvements
The investigation highlighted the failure to communicate rapidly deteriorating visibility from the Weather Bureau to the tower, leading to stricter requirements for relaying RVR data.