NTSB Identification: ERA14LA147
14 CFR Part 91: General Aviation
Accident
occurred
Saturday, March 08, 2014
in
Fairhope, AL
Probable Cause Approval Date:
06/22/2015
Aircraft:
CESSNA 172D, registration:
N2755U
Injuries: 1 Serious.
NTSB
investigators may not have traveled in support of this investigation
and used data provided by various sources to prepare this aircraft
accident report.
The pilot reported that the airplane entered the downwind leg of the traffic pattern behind a large helicopter and that he followed the helicopter closely in the traffic pattern.
While on short final approach, the airplane remained behind the helicopter as the helicopter was terminating its approach about three-quarters down the runway. When the airplane was about 30 ft above the approach end of the runway, it banked and pitched suddenly, and it then impacted the ground. The pilot reported no mechanical malfunctions or failures with the airplane that would have precluded normal operation nor were any found during a postaccident examination of the wreckage.
A simulation modeling the helicopter’s trailing vortex-generating tendencies showed that vortices of significant strength were likely present at the airplane’s reported position at the time of the upset.
If the pilot had maintained adequate separation from the large helicopter during the approach to landing, the airplane likely would not have encountered the trailing vortices that caused the loss of airplane control.
The pilot reported that the airplane entered the downwind leg of the traffic pattern behind a large helicopter and that he followed the helicopter closely in the traffic pattern.
While on short final approach, the airplane remained behind the helicopter as the helicopter was terminating its approach about three-quarters down the runway. When the airplane was about 30 ft above the approach end of the runway, it banked and pitched suddenly, and it then impacted the ground. The pilot reported no mechanical malfunctions or failures with the airplane that would have precluded normal operation nor were any found during a postaccident examination of the wreckage.
A simulation modeling the helicopter’s trailing vortex-generating tendencies showed that vortices of significant strength were likely present at the airplane’s reported position at the time of the upset.
If the pilot had maintained adequate separation from the large helicopter during the approach to landing, the airplane likely would not have encountered the trailing vortices that caused the loss of airplane control.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The pilot’s failure to maintain adequate separation from a helicopter during the approach to landing, which resulted in an encounter with the helicopter’s trailing vortices, a loss of airplane control, and impact with terrain.