Accident to the Piper PA30 registered N7977Y on 02/03/2021 at Courcelles-sur-Viosnes
Arrêt du moteur droit en circuit d'aérodrome, diminution de la puissance du moteur gauche, atterrissage forcé dans un champ, en instruction
During a training flight with an instructor, the pilot experienced a right engine failure in the downwind leg. The instructor then took the controls. After processing the failure of the right engine and making an input for full power on the other engine, he was unable to hold level flight. Unable to reach the runway, the instructor landed in a ploughed field.
The right engine shut-down was due to the clogging of the injector nozzle of cylinder No 3 by the build-up of contamination in the damaged area of the injector line. This contamination was able to reach the injector nozzle because the strainer of the system regulating the fuel flow to the cylinders (FSI) was no longer fulfilling its function due to distortion. This distortion, which does not cause any particular difficulty in removing or reinstalling the strainer, was not detected during the last annual inspection. The investigation was unable to determine when the strainer was distorted. The damage to the injector line probably occurred when the injector nozzle was cleaned with unsuitable tools. A precise date for this damage, which occurred before the last annual inspection, could not be determined.
The following factors may have contributed to it being impossible to hold level flight and reach the runway:
- A possible late retraction of the landing gear.
- A possible failure of the left engine which might not have provided full power when called upon. During the test bench tests, the requested marked, high-amplitude speed increases were erratic. This behaviour is possibly related to an incorrect FSI adjustment that resulted in an air-fuel mixture which was too rich in the cylinders. The investigation was unable to determine the reasons for the adjustment non-conformities observed on the FSI. Other than the strainer check, no work on the FSI was recorded in the documentation made available to the BEA. The FSI had probably not been overhauled since the last engine overhaul carried out more than 20 years before.