N196TP

HISTORY OF FLIGHTOn March 8, 2017, about 1343 central standard time, a Grob Aircraft AG G120TP-A, N196TP, was substantially damaged when it was involved in an accident near Abbeville Municipal Airport (0J0), Abbeville, Alabama. The flight instructor and a pilot undergoing instruction (PUI) sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.

The flight instructor stated that a preflight inspection was performed and no discrepancies were reported. The flight departed about 1303 from Dothan Regional Airport, Dothan, Alabama with about 1/2 capacity fuel load.

Review of video recorded by an onboard audio/video device revealed that about 70 seconds after takeoff the continuous ignition was set to the “OFF” position and remained in that position for the duration of the video recording. The flight proceeded near Lake Eufaula, where according to the flight instructor, upon arrival, the Crew Awareness System (CAS) circuit breaker was pulled in accordance with the operator's developed upset prevention and recovery training (UPRT) checklist. The recorded onboard video showed that the CAS circuit breaker remained pulled for the duration of the video recording.

The flight instructor further stated that the PUI performed training maneuvers. Data downloaded from the airplane’s Flight Data Monitoring (FDM) device showed that this portion of the flight was about 22 minutes in duration. After completion, the flight instructor took the controls and proceeded to fly to 0J0, where he intended to demonstrate a simulated loss of engine power or practice power off (PPO) maneuver with plans to terminate it with a low pass over the runway.

According to the recorded video and FDM data, about 1340:54, the flight instructor discussed performing the simulated engine out and confirmed the power lever was at flight idle. At that time the engine indications were normal. At 1340:58, while flying about 3,350 ft pressure altitude and about 1.8 nautical miles southeast of the approach end of runway 35 at 0J0, the flight instructor pulled the condition (or propeller rpm) lever to, “a low idle.” He appeared to have a light touch (not quick or jerky) and moved it to the “low RPM” gate. It did not appear that the flight instructor lifted or moved the condition lever aft of the “low RPM” gate. The instructor pilot then appeared to verify it was still at the gate by wiggling the condition lever. One second later, at 1340:59, as the condition lever was at the gate (same position), the engine parameters consisting of N1, oil pressure, and turbine outlet temperature (TOT) immediately began dropping outside previously stable levels as indicated in the video recording of the multi-function display (MFD), and in the FDM data, which was not aurally annunciated.

The flight continued towards 0J0 and at 1341:46, while about 1,600 ft southeast of the approach end of runway 35, the FDM data revealed oil pressure levels that would have resulted in a displayed “lo oil press” warning indication on the PUI primary flight display (PFD). About 5 seconds later, the airplane was abeam the approach end of runway 35, east of it, about 2,500 ft pressure altitude. The flight instructor added that he continued the maneuver while circling to land, and video indicated that at 1341:56, he acknowledged that the airspeed, which about that time was at 95 knots, was slow. Seconds later he acknowledged being a “little bit high” and discussed extending the upwind leg of the airport traffic pattern.

According to the video and FDM data, about 1342:19, while on the downwind leg of the airport traffic pattern for runway 35, the flight instructor began turning onto the crosswind leg of the airport traffic pattern, and discussed the importance of best glide speed in relation to the distance that the airplane could glide in an engine out condition. About 21 seconds later, while flying about 1,480 ft pressure altitude and 104 knots, the instructor discussed being at 1,400 ft mean sea level (msl) and appeared to be on the downwind leg of the airport traffic pattern for runway 35.

The flight instructor further stated that he lowered the landing gear and advised that he would, “…hold off on the flaps for now.” The flight continued on the downwind leg of the airport traffic pattern for runway 35 and about 1343:09, when abeam the approach end of the runway about .5 nautical mile, or the “low key” position (see figure 1), the airplane was at 800 ft pressure altitude and 91 knots. About 5 seconds later, the audio recorded the first “chirp” from the aircraft’s stall warning horn, and simultaneously, the PUI stated that he saw mist/smoke coming from the right side of the engine and that he smelled fuel, which he announced. The flight instructor turned onto the base leg of the traffic pattern, though he later indicated he did not smell fuel at that time. They both then noted a vapor outside from the right side of the engine, followed by a puff of white smoke.

The flight instructor later reported it was at that moment, at 1343:30, that he recognized that, “the engine had failed” which he realized as he had lost 10 knots of airspeed and the rate of descent increased. The video showed that the flight instructor stated, “start, start the engine”, while he later reported he continued to fly the airplane. The flight path depicted a continuing left turn towards the runway, and the FDM data showed N1, N2, and TOT climbing consistent with a restart attempt at 1343:41. The airplane at that time was under 100 ft above ground level as determined by the radar altimeter. While flying about 61 knots indicated airspeed, the airplane collided with trees, then the ground. The video portion of the recording ended at 1341:02, though audio continued to be record. The sound of impact was recorded at 1343:44, while audio and data ended two seconds later.

Both pilots exited the airplane, and after notifying the operator of the accident, they walked to the airport and were taken to a hospital for treatment.

Figure 1 - Illustration From Airplane Flight Manual Depicting High and Low Key Positions

AIRCRAFT INFORMATIONEach seat was equipped with an Electronic Flight Instrument System (EFIS) PFD and MFD, called integrated display units (IDU). Integrated into them was a CAS which monitored a wide variety of parameters and provided aural and visual annunciations for conditions that demanded pilot awareness, such as low oil pressure which was a red warning on the IDU and a synthesized spoken indication to the flightcrew by announcing “check oil”; however, with the CAS circuit breaker pulled the low oil pressure would not have been annunciated aurally.

The airplane was also equipped with a solid state digital FDM system which recorded over 100 aircraft and flight parameters as well as audio and video signals, and an onboard image recorder that recorded and retained video and audio to a secure digital (SD) card. The FDM with SD card, onboard image recorder with SD card, and each EFIS display were retained by NTSB and sent to the NTSB Vehicle Recorder’s Laboratory for read-out.

According to individuals who flew the airplane with their instructor on two separate flights earlier that day, there were no reported engine abnormalities during either flight which each lasted 1.4 hours. The PUI for each flight reported the PPO maneuver was not performed.

AIRPORT INFORMATIONEach seat was equipped with an Electronic Flight Instrument System (EFIS) PFD and MFD, called integrated display units (IDU). Integrated into them was a CAS which monitored a wide variety of parameters and provided aural and visual annunciations for conditions that demanded pilot awareness, such as low oil pressure which was a red warning on the IDU and a synthesized spoken indication to the flightcrew by announcing “check oil”; however, with the CAS circuit breaker pulled the low oil pressure would not have been annunciated aurally.

The airplane was also equipped with a solid state digital FDM system which recorded over 100 aircraft and flight parameters as well as audio and video signals, and an onboard image recorder that recorded and retained video and audio to a secure digital (SD) card. The FDM with SD card, onboard image recorder with SD card, and each EFIS display were retained by NTSB and sent to the NTSB Vehicle Recorder’s Laboratory for read-out.

According to individuals who flew the airplane with their instructor on two separate flights earlier that day, there were no reported engine abnormalities during either flight which each lasted 1.4 hours. The PUI for each flight reported the PPO maneuver was not performed.

WRECKAGE AND IMPACT INFORMATIONExamination of the accident site and wreckage at the accident site was performed by representatives of the operator, airframe manufacturer, and engine manufacturer who were overseen by a Federal Aviation Administration inspector. The airplane was located in a wooded area about 775 ft and 183° from the approach end of runway 35 at 0J0.

Examination of the accident site revealed the airplane was upright with the left wing attached, while the right wing was separated at the wing root and found resting near the right side of the fuselage with several tree impacts to the leading edge. The empennage was displaced nearly 90° to the left, and the flaps were retracted. Both main landing gear were extended but were collapsed to the left. All components necessary to sustain flight remained attached or were found in close proximity to the main wreckage. Examination of the cockpit revealed the “CAS Mute” circuit breaker was out, the continuous ignition switch was off, the power lever was at flight idle and the condition lever was at the cutoff/feather position.

Examination of the engine at the accident site revealed it remained securely attached to the airframe. The propeller gearbox was fractured from approximately the 3 o’clock to 9 o’clock p...