Loss of Control in Flight · NTSB WPR14FA330
DAVID FITZGERALD ZENITH — WARREN, ID
| Date | August 5, 2014 |
| Location | WARREN, ID |
| Aircraft | DAVID FITZGERALD ZENITH (amateur-built) |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Uncontrolled descent Collision with terr/obj (non-CFIT) |
| Pilot age | 57 |
| Pilot total time | 414 hrs · Building experience |
| Time in type | Unknown |
| Fatalities | 2 |
Probable cause
NTSB findings
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained - C
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Angle of attack-Not attained/maintained - C
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
- Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-High density altitude-Effect on operation
- Environmental issues-Physical environment-Terrain-Mountainous/hilly terrain-Contributed to outcome
What happened
The pilot and a passenger were conducting cross-country flights across multiple days in remote mountainous areas. Data downloaded from the airplane's multifunction display showed, for the accident leg, a flight track that meandered from the last departure point toward the day's intended destination, which was about 19 nm northwest of the accident site. The track followed the contour of the area's mountainous terrain, was not a direct route, and had many turns and route reversals. The airplane's altitude remained mostly constant. In the last minute of flight, the airplane was in a gradual climb, and the airspeed decreased from about 50 knots to the last recorded airspeed of about 35 knots. During the last few seconds of flight, the pitch became nose down, and the airplane rolled to a 90-degree angle. Onsite wreckage documentation indicated that the airplane collided with the sloping terrain in a nose-down attitude. It is likely that the pilot increased pitch to establish a climb angle to clear the terrain but inadvertently exceeded the airplane's critical angle-of-attack and entered a stall from which he was unable to recover.
The density altitude at the time of the accident was about 10,381 ft. Operation at a high density altitude can adversely impact airplane performance. Postaccident documentation of the wreckage and data downloaded from the airplane's multifunction display did not reveal evidence of a mechanical malfunction or failure that would have precluded normal operation.