20000325017719I

(-23)On March 25, 2000, at approximately 1007 local time, an Aerostar 601P, N15BA, made an off airport landing approximately 6 miles east of the Sinton, Texas airport. The commerical instrument rated pilot reported a loss of power on both engines. The part 91 IFR flight consisting of the pilot anf five passengers departed from corpus christi, Texas (crp) enroute to huntsville, Texas (uts). According to the pilot, while climbing at approxiamtely 7000 feet MSL, he observed high oil temperature and low oil pressure on the left engine. He elected to return to the departure airport, but upon descending suffcient altitude. He then diverted to the Sinton airport. The aircraft sustained moderate damage from the gear up landing in soft dirt. Both propellers were also damaged. One passenger sustained minor injuries. An on-site inspection of the aicraft revealed that the pilot landed with gear and flaps up. Neither propeller appeared to have been feathered. All fuel tanks were nearly full of what appeared to be the proper fuel (avgas). Fuel sampled were drained form each fuel tank with no visible evidence of fuel contamination. On April 14, 2000, a post incident was conducted on both engines. The propeller of left engine was noticeably more difficult to turn by hand than the right engine. An inspection of the left engine oil filter element revealed an abnormal amount of non magnetic metal which appeared to be aluminum. A cold engine differential compression check was conducted on both engines with the following results: (see attachment). Several of the top spark plugs from the left engine appeared to be running very hot. The number 3 poston, as inspected through the spark plug hole, appeared to have localized detonation damage at the outer perimeter. The piston also had many small pit marks from foreign object contact. The no.3 spark plug center electrode was severely damaged and partially missing. The no.3 fuel nozzle was removed, inspected, and flow checked for obvious discrepancies. No nozzle discrepancies were noted. Engine ignition timing was verified to be 20 degrees btdc as recommended. The right engine was also inspected for discrepancies which could preclude the engine from producing full power. Other tham damage attributed to the off airport landing, the following discrepancies were noted: excessive play in the turbo controller wastegat e linkage, and excessive wear in the mixture control linkage near the fuel servo unit. Although these discrepancies could have an adverse effect on engine full power performance, they appeared to be preexisting wear conditions and not recent failures. During the interview with the pilot, he stated that his normal leaning procedure in this aircraft was to begin leaning in the climb configuration at approximately 3000 to 4000 feet MSL. He would normally lean the mixture until the tachometer indicated a slight engine RPM drop. At that time he would enrichen the mixture until slightly past the point where the RPM recovered. This procedure would be repeated upon reaching cruise altitude. When asked about the use of the EGT gauge, he stated that he did not use the EGT to lean. When asked about the significance of the EGT red lines, he stated that they were do not exceed marks. He could not explain how he ensured these limits were not exceeded. The aircraft flight manual prohibits mixture leaning about 75% power. A post incident weight and balance calculation indicates the aircraft exceeded the maximum allowable takeoff weight by over 20 pounds at the time of departure.