What happened
On June 10, 2011, a Piper PA-28R-201 (registration PH-SAC) was conducting a flight test for a Commercial Pilot License (CPL) evaluation. The flight began at Maastricht Aachen Airport, proceeding to Kempen Airport for several touch-and-go maneuvers. During the final approach at Kempen Airport, the crew attempted to extend the landing gear, but while the main gear indicators turned green, the nose gear indicator remained unlit, accompanied by a red 'gear unsafe' warning.
After attempting to troubleshoot the issue by cycling the gear, the crew decided to divert to their home base at Maastricht Aachen Airport to access better maintenance facilities and emergency services. During the approach at Maastricht Aachen, air traffic control informed the crew that the nose gear doors were open, but the gear itself had not deployed. After circling the field for approximately 30 minutes and making several unsuccessful attempts to extend the nose gear, the pilot performed an emergency landing on runway 03. The pilot attempted to use the elevator to keep the nose elevated for as long as possible, but the nose eventually struck the pavement, causing substantial damage to the nose gear structure, engine cowling, exhaust, and propeller. Both the examiner and the student remained uninjured.
The investigation
The investigation focused on why the nose gear failed to extend despite the gear lever being selected. Investigators examined the aircraft's windshield heating system, which uses heated air from the engine exhaust to prevent condensation. The inspection revealed that a flange from the steel sleeve surrounding the exhaust had broken off. This detached component had migrated into the nose gear assembly, physically obstructing the deployment mechanism.
Furthermore, the investigation looked into the integrity of the exhaust sleeve. The hole in the sleeve where the flange was attached appeared irregular, and the use of pop rivets instead of a welded connection suggested that the flanges were likely added via a non-standard modification rather than during original manufacturing. The operator was unable to provide documentation for any such modification or repair.
Findings
- A broken flange from the windshield heating system's air duct entered the nose gear bay.
- The broken flange blocked the nose gear from extending properly.
- The exhaust sleeve showed evidence of non-standard assembly using pop rivets rather than permanent welds.
- There was no available maintenance or modification record for the exhaust sleeve assembly.