What happened
On 12 May 2023, a Cessna 150M, registration EI-HJX, was conducting a general aviation flight near Gorey, Co. Wexford, carrying an instructor and a student. While cruising at approximately 2,500 feet, the instructor noticed a pungent smell in the cockpit. To improve ventilation, the aircraft doors were unlatched, but shortly thereafter, hot engine oil began leaking from the instrument panel and onto the floor of the cockpit. Simultaneously, the engine oil pressure gauge indicated zero pressure.
Recognizing the emergency, the instructor initiated emergency landing procedures and broadcast a Mayday call. The pilot selected an agricultural field near Tara Hill and executed a successful precautionary landing. The aircraft sustained minor damage, and both occupants evacuated the aircraft safely without any injuries.
The investigation
The AAIU examined the aircraft's instrument panel and discovered oil pooling near the transponder unit. Upon inspecting the area behind the panel, investigators located a fractured pipe that supplies engine oil to the pressure gauge.
Detailed examination of the fractured component revealed that the part was not a single continuous unit, but rather two separate metal pipe sections that had been cut with a hacksaw. These two sections had been joined using a plastic sleeve, which was held in place by plastic tie-wraps and locking wire. The investigation found that the plastic sleeve had split at the junction where the two metal ends met, allowing the pressurized oil to escape into the cockpit.
Findings
- The primary cause of the oil leak was the failure of an unapproved repair involving the joining of two metal pipes with a plastic sleeve and tie-wraps.
- The use of such a method is not an authorized repair scheme for this aircraft type.
- The instructor's proficiency in emergency landing drills contributed to the safe outcome of the incident.