Goodyear, AZ, USA
N154BY
DIAMOND AIRCRAFT IND GMBH DA 40 NG
The student pilot had been signed off for a solo instructional flight. He performed the preflight check, including a check of the engine control unit (ECU), and noted no discrepancies. The run-up and initial takeoff were normal. However, during the takeoff climb out, the student pilot noted an engine power change followed by an ECU A and ECU B failure annunciation. The student pilot was able to land in an open field and impacted several drainage ditches, resulting in substantial damage to the right wing. Inspection of the engine revealed that the hose that connects the air inlet to the turbocharger inlet was found to have de-laminated or collapsed. The loss of engine power was likely due to a partial vacuum in the turbo inlet and prevented the turbo from supplying the correct air inlet pressure to the engine, thus reducing power output. The investigation found that a generic air induction hose had been installed on the accident airplane that was not part number specific. The Diamond illustrated parts breakdown calls for a specific part number for two flexible induction hoses. The operator reported that they inspected their fleet of airplanes and replaced the generic hoses with Diamond Aircraft Industries Inc. (DAI) hose.
On April 20, 2017, at 0719 hours mountain standard time, a Diamond Aircraft Industries DA-40NG, N154BY, was substantially damaged when it was involved in an accident near Goodyear, Arizona. The student pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the student pilot, he was on his first solo flight after completing his pre-solo checkout exam. During the preflight check, the student pilot performed a check of the engine control unit (ECU). There were no discrepancies noted with the ECU, and the preflight check, run-up, taxi, and initial takeoff were normal. During the takeoff climb out, about 400 ft above ground level (agl), he heard a power change from the engine. As the student pilot checked the engine load indicator, which read 35%, he moved the power lever up and down to see if he had engine control; however, the engine load indicator remained at 35%. About 5 seconds later, he observed two annunciators illuminated, ECU A FAIL and ECU B FAIL. The airplane’s flight and systems data from the accident flight, captured by its Garmin G1000 integrated flight deck system download, revealed that the engine lost power near the departure end of runway 21 at an altitude of 1,560 ft. mean sea level and an airspeed of 88.6 knots. The data also revealed a sudden drop in engine load from 97% to 39% in less than 4 seconds. The student pilot reported that, because the flight school’s standard operating procedures advised students not to turn back to the airport below an altitude of 1,000 ft agl, he did not have sufficient altitude to turn back to the runway. The student pilot maneuvered to a field to the right of the airplane and attempted to attain an airspeed of 88 knots (glide speed). However, he stated that his altitude was low, and he did not think he was going to be able to clear the power lines around the field, so he decided to fly under the power lines. According to the pilot, as the airplane flew under the power lines, the airplane struck the bottom power line and a white flash appeared in the cockpit. The pilot also reported that, when the airplane first touched down in the field, it bounced. The operator reported that the airplane then impacted two drainage ditches before it came to rest near a third drainage ditch, resulting in substantial damage to the right wing. The pilot reported that he then switched off the fuel pumps, opened the canopy, and exited the airplane. A review of flight and systems data from the G1000 revealed both a nominal rpm change and a decrease in fuel flow during the takeoff; there was no engine roughness and no significant changes in oil temperature, oil pressure, and engine temperature. Postaccident examination of the turbocharger system revealed no visible abnormalities. When it was disassembled, evidence of oil loss was found at the turbocharger seals and outlet; the turbocharger was found to spin freely. Further inspection of the system revealed that the interior lining of the air induction hose between the alternate air valve and turbocharger showed signs of deterioration. The air induction hose was installed and tested on another aircraft. During the test, the engine lost power. A subsequent inspection of the air induction hose revealed that its inner liner had separated and collapsed in such a way that it prevented sufficient air intake to the turbocharger. The investigation found that a generic air induction hose had been installed on the accident airplane that was not part number specific. The Diamond illustrated parts breakdown calls for a specific part number for two flexible induction hoses. The operator reported that they inspected their fleet of airplanes and replaced the generic hoses with Diamond Aircraft Industries Inc. (DAI) hose.
Loss of engine power due to the installation of an improper air induction hose, which failed and prevented sufficient air intake to the turbocharger.
Source: NTSB Aviation Accident Database
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