Incident Overview
A Piper PA-31 aircraft conducting a Part 135 training flight experienced a power loss shortly after takeoff. The pilot-in-command (PIC), who also served as the chief pilot, had earlier requested adjustments to the engines for improved performance. The director of maintenance subsequently adjusted the fuel mixture control units on both engines. The PIC and a dual student then departed for the training flight without noting any problems during preflight inspection, engine start-up, taxi, engine run-up, or the initial takeoff roll.
Flight Details
During climbout, the airplane was unable to maintain a climb. The PIC observed that the right engine had a power problem, indicated by low manifold pressure. To reduce the descent rate, the PIC feathered the right propeller. Despite this action, the airplane continued to descend. The dual student then executed a forced landing on rough terrain.
Examination Findings
An examination of the spark plugs after the incident revealed that the engines had been operating with an excessively rich mixture. The density altitude at the time was reported as 5,560 feet. This was the dual student's first flight in a Piper PA-31 aircraft.