What happened
On May 22, 2018, an Antonov AN-32A, registration OB-2098, was performing a cargo flight from Jorge Chávez International Airport to Las Malvinas Aerodrome. While cruising at 6,000 feet, approximately 15 nautical miles northwest of Las Malvinas, the crew observed a low fuel pressure warning for the number one engine. Shortly after, the engine's RPM began to decrease, leading to a complete engine shutdown and the automatic feathering of the propeller.
The crew notified air traffic control and performed a visual approach to runway 17. The aircraft landed without further incident. However, during taxiing toward the parking area, the tower informed the crew that fuel was leaking from the side of the number one engine. Upon inspection, the crew discovered that a fuel supply hose had become disconnected.
The investigation
The investigation focused on the cause of the fuel supply failure and the maintenance practices of the operator, Aerolínea del Caribe Perú S.A.C. Investigators examined the disconnected hose (P/N 1Y27-15K) and found that the component itself was in good physical condition, with all clamps and safety wires intact.
Technical analysis revealed that the disconnection occurred gradually and went undetected during scheduled inspections. It was established that during previous "Check B" or 50-hour inspections, maintenance personnel had been pulling on the fuel hoses to verify their security and tightness. This specific physical action—pulling on the hoses—was not an authorized procedure under the aircraft's approved maintenance program or the technical task cards.
Findings
- The primary cause of the incident was the uncommanded shutdown of the number one engine due to a lack of fuel supply resulting from the disconnection of the fuel supply hose from the low-pressure pump.
- A contributing factor was the application of an incorrect maintenance task, specifically pulling on the fuel hoses to check them, which is not part of the approved inspection procedures.
- The crew performed the emergency procedures correctly, and the aircraft was airworthy at the time of departure.