Diamond Aircraft Ind Inc DA 20-C1 N176MA accident near Linden, New Jersey

Probable cause

The flight instructor's inadequate preflight planning and his decision to take off with the airplane at a high gross weight in high temperature conditions that degraded the engine’s available power and his subsequent failure to maintain airspeed while attempting to return to the departure airport, which resulted in the airplane exceeding its critical angle-of-attack and experiencing an aerodynamic stall.

NTSB analysis

The flight instructor was conducting an introductory flight for the passenger. Witnesses reported observing the airplane lift off about two-thirds down the 4,140-ft-long, asphalt runway and then struggle to gain altitude. The passenger reported that, after takeoff, the flight instructor told him that the engine was not "making power." The flight instructor declared an emergency and was returning to the departure airport when the airplane stalled and impacted the ground about 1/2 mile northwest of the airport. Postaccident examination of the airframe and engine did not reveal any discrepancies that would have precluded normal operation.

Weight and balance calculations revealed that the airplane was likely at or above its maximum allowable takeoff weight during the accident flight. Further, the temperature about the time of the accident was about 94 degrees F, and the estimated density altitude at the airport was about 2,200 ft mean sea level. Based on these conditions, if the engine had been operating perfectly, its available power production would have been between about 81 and 85 percent. Therefore, it is likely that these conditions, in combination with the airplane being near or slightly above its maximum allowable weight, reduced the airplane's climb performance and that, while attempting to return to the airport, the pilot failed to maintain adequate airspeed and flew the airplane beyond its critical angle-of-attack, which led to an aerodynamic stall.

The flight instructor was ejected from the airplane during the impact after the right seatbelt quick release hook separated from its fuselage anchor. Examination of the quick release hook revealed that it was bent out of the plane of the attachment and twisted. In addition, the hook closure latch was also distorted and deformed. The combined deformations of the hook and latch allowed the hook to disengage. Although it is possible that the deformation occurred during the accident impact, it is more likely that preexisting deformation was present. The airplane had been operated for about 38 hours since its most recent 100-hour/annual inspection, which was performed about 3 weeks before the accident. A condition inspection of the restraint system was required to be performed during this inspection; however, no record was found indicating whether the condition inspection was performed.

Text from the NTSB. Open the NTSB docket for ERA13FA259 for the full record.