What happened
On October 30, 2010, at approximately 14:30 UTC, a Piper PA-25-235, registration OB-935, operated by SOTENZA S.A.C., was performing agricultural spraying operations near Paramonga, Lima, Peru. The aircraft had departed from the Cerro Blanco landing field with the intention of applying chemicals at the Don Enrique plantation.
While performing its third application pass, the pilot experienced intense vibrations. Upon climbing to a higher altitude, the pilot observed smoke and flames originating from the lower, rear, and right side of the engine compartment. Following established emergency procedures for in-flight engine fires, the pilot executed a forced landing in an unplanted field. Although the pilot successfully evacuated the aircraft, the subsequent fire consumed the entire airframe. There were no injuries to the pilot.
The investigation
The CIAA investigation examined the aircraft's maintenance history, the pilot's experience, and the operational procedures of the operator. Investigators reviewed the engine and propeller components, as well as the company's maintenance and operations manuals. The investigation also looked into the adequacy of the company's emergency response capabilities and the completeness of their technical documentation.
Findings
- The aircraft's maintenance and inspection programs (PIA and MGM) lacked specific procedures to check the structural condition of the exhaust system, specifically regarding corrosion, deformation, or cracks in the intermediate and external exhaust tubes.
- The inspection and pre-flight checklists did not include verification of the attachment of the exhaust vent pipes.
- The operator's General Operations Manual (MGO) was incomplete, missing several pages, and contained an outdated emergency contact directory.
- The company's emergency response plan (PPA) lacked updated procedures for immediate intervention by ground support personnel and did not ensure sufficient communication equipment or fire suppression capabilities for the support vehicle.
- The lack of specific inspection procedures for the exhaust system and its vent attachments contributed to the undetected condition that led to the fire.