Primary finding
Probable cause
The malfunction of a magneto resulting in a partial loss of power over unsuitable terrain.
Investigator assessment
Analysis narrative
After takeoff the pilot noted the engine running 'rough. He flew the traffic pattern and the engine continued to lose power. On final approach he stated the engine would not develop enough power to make the runway and he executed a forced landing into a marsh short of the runway. Examination of the engine after recovery revealed the right magneto was worn and would only produce partial power.
Source record
Factual narrative
On December 4, 1994, about 0605 Atlantic standard time, N404FL, a Piper PA-28-140 crashed near Fajardo Airport, Fajardo, Puerto Rico, while on a 14 CFR Part 91 personal flight. N404FL was registered to the pilot Mr. Jesus M.A. Molina. Visual meteorological conditions prevailed at the time and no flight plan was filed for the proposed flight to Vieques, Puerto Rico. The airplane was substantially damaged and the commercially-rated pilot reported no injuries. The flight had just originated at the time of the accident. The pilot stated he took off on runway 07 and noted a rough running engine. He then flew a traffic pattern to return to the airport. On final approach the engine lost power and he executed a forced landing to a marsh short of the runway. The engine was removed from the airplane for teardown and examination by FAA personnel. The examination was conducted on February 2, 1995. No discrepancies were noted. The carburetor and magnetos were removed and sent to a repair station for further examination. The carburetor was bench checked and flowed normally. The magnetos were bench examined and the left magneto checked to be operable with normal wear noted. The right magneto produced minimal spark, and would not fire normally in the test stand. -