What happened
On June 3, 2004, a Piper PA-23 Aztec, registration CS-AGW, departed from runway 35 at Tires Municipal Aerodrome for a multi-engine qualification training flight. The flight, conducted by an instructor and a student pilot, was designed to practice asymmetric power maneuvers, specifically simulating engine failures during approach and landing.
During the training session, the student pilot initiated an approach simulating a failure of the right engine. As the aircraft reached the flare for landing, the student pilot reduced the power on the left engine to idle. At this moment, an audible gear warning sounded, and air traffic control instructed the crew to perform an immediate go-around. The crew realized that the landing gear had not been extended.
As the aircraft touched the runway, both pilots noticed the propeller blades making contact with the pavement. The instructor took control, applied power to both engines, and performed a go-around to land again. The incident resulted in no injuries to the crew, but caused damage to the propeller tips and a scrape on the left main gear door.
The investigation
The GPIAAF investigation focused on the sequence of events during the simulated emergency. The investigation established that the training procedure required the right engine to be maintained at 2,175 RPM to simulate the aerodynamic effects of a feathered propeller. Because the left engine was still producing power during the approach, the cockpit's visual gear warning light (which activates when power is reduced on one engine while the gear is up) did not illuminate.
The audible gear warning only triggers when both power levers are reduced below 12 inches of manifold pressure. This warning only sounded once the student pilot had already reduced the left engine power, at which point the aircraft was already in the landing phase.
Findings
- The primary cause of the accident was deficient checklist discipline by the instructor, specifically the failure to perform the landing checklist item regarding landing gear extension and the verification of the three green lights indicating the gear was down and locked.
- The crew failed to confirm the gear position prior to the landing attempt.
- The propeller blades on the left engine were cut by the impact, while the right engine blades were bent.