What happened
On April 26, 2018, a Cessna 152 aircraft, registration VT-PTD, operated by Falcon Aviation Academy, was conducting an instrument flying training sortie near Faizabad. The flight, which included a flight instructor and a trainee pilot, was performing a planned GPS-assisted approach to Runway 12.
During the final approach, the crew noticed engine vibrations and a drop in RPM. The instructor took control of the aircraft to manage the instability, but the engine subsequently stopped. While attempting to restart the engine, the crew found the engine would not come live. With the aircraft losing altitude, the instructor executed a forced landing on the sandy bed of the Sary and River. The aircraft touched down on its main landing gear and rolled approximately 213 feet. As the nose gear made contact with the soft sand, the aircraft sank and toppled over. Both occupants successfully evacuated the aircraft without injury, though the aircraft sustained significant damage to its wings, engine mounts, and landing gear.
The investigation
AAIB India investigators examined the wreckage and engine components to determine the cause of the power loss. The investigation focused on the engine's mechanical state, the maintenance history of the aircraft, and the crew's actions during the emergency. The inquiry also reviewed the aerodrome's security and the academy's training manuals regarding special VFR operations.
Findings
- The engine vibration and subsequent loss of power were caused by spark plug fouling.
- During the execution of emergency procedures, the engine stopped, potentially due to the improper leaning of the fuel mixture or the sudden opening of the throttle.
- A restart attempt failed because the starter motor's gear teeth were broken and the starter body had developed a crack.
- Detailed examination of the engine revealed that a fuel accelerating jet nozzle had been improperly installed during the last overhaul.
- Evidence suggested that maintenance certifications might have been completed without the actual physical maintenance being performed.
- The aircraft's nose gear sank into the river bed sand, which caused the airframe to topple.
Safety action
- The operator should reinforce training regarding the dangers of sudden throttle movements during engine roughness procedures.
- The operator must ensure that all maintenance tasks are performed meticulously and that improper installations, such as the fuel jet nozzle, are addressed with the overhaul organization.
- The DGCA should audit the maintenance practices of the flight academy and ensure that training manuals correctly cite regulations regarding Special VFR operations.