FTW99FA199

During takeoff, the twin-engine airplane was observed to roll left, pitch nose down, and impact terrain shortly after the pilot reported to ATC that he had a problem. Witnesses reported that the left engine was producing black smoke during the takeoff roll. One witness stated that the airplane had slowed to approximately 60-70 mph prior to rolling to the left. A mechanic, who worked on the airplane prior to the accident, stated that the pilot reported being unable to maintain manifold pressure (MP) with the left engine. The mechanic found that the left engine's rubber interconnect boot, which routes induction air between the turbocharger controller elbow and the fuel servo, was 'gaping open.' The mechanic reseated the boot and tightened the clamp. The pilot flew the airplane and reported no problems. During a second flight, the pilot reported that the left engine was again unable to maintain MP. Prior to the accident flight, the pilot informed the mechanic that the 'hose had slid off again' and that it had been reinstalled and he 'felt sure it was o.k.' A witness stated that he saw the pilot working on the left engine the morning of the accident. At the accident site, the left engine's interconnect boot was found disconnected. The clamp securing the boot was not located. No other pre-impact anomalies were found with the engines, propellers, turbochargers, or fuel servos.

History of flight

On July 23, 1999, at 1113 central daylight time, a Smith Aerostar 601P twin-engine airplane, N345LS, impacted terrain following a loss of engine power during the takeoff climb from the Wiley Post Airport, near Bethany, Oklahoma. The airplane was destroyed by impact forces and fire. The instrument rated private pilot and his pilot rated passenger were fatally injured. The airplane was owned and operated by the pilot under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal flight destined for San Angelo, Texas. The pilot had filed an instrument flight rules flight plan for the trip; however, he did not open the flight plan at the time of departure.

According to a pilot rated witness positioned behind the accident airplane on runway 17L, "the airplane's left engine was producing a black smoke during the takeoff roll." The witness stated that the airplane started to drift to the left after the takeoff roll. Shortly after takeoff, the witness heard the pilot transmit to the tower that "he had a problem." The witness stated that the pilot did not elaborate on the problem. Immediately after the radio call, the airplane appeared to "pitch nose high simultaneously yawing and rolling to the left." The witness reported that he saw the airplane roll over, nose down while turning and impact the ground.

According to a second witness driving south on a street parallel to the runway, "the airplane's left engine was producing puffs of black smoke." The witness stated that "the exhaust was not in a steady stream like normal." Instead, the exhaust produced by the left engine was intermittent as if the "engine was missing or surging."

Two witnesses, located north of the accident site/south of the departure runway, stated that they saw the airplane takeoff. Both witnesses reported that the airplane appeared "much lower and slower than the other twin-engine airplanes that departed that runway." One witness stated that the airplane slowed to approximately "60-70 mph" and lost about 150 feet of altitude after takeoff. Both witnesses stated that the engines sounded "normal." They observed the airplane roll left and pitch nose down. One witness stated that as the airplane did this, it appeared as if the "left propeller was slowing down." The airplane then disappeared behind a building, and the witnesses heard the sound of impact and saw a plume of smoke rise from behind the building.

Personnel information

The private pilot held airplane single engine land, airplane single engine sea, airplane multiengine land, and instrument airplane ratings. On December 10, 1997, he was issued a second class medical certificate with no limitations. The pilot's logbook was not located during the investigation. According to an air race application dated June 27, 1999, the pilot had accumulated 1,500 hours of total flight time, of which approximately 100 hours were in the accident airplane. On the application, the pilot listed his last biennial flight review date as August 1998. The type of airplane used for the review was not listed. The pilot purchased the accident airplane in September 1998, and completed a 5-hour flight, 25-hour ground instruction course, which was required for insurance coverage. According to the company that performed the insurance checkout for the pilot, emergency procedures were covered in both the flight and ground instruction phases of his training.

Aircraft information

The accident airplane (serial number 61P-0315-085) was manufactured on May 18, 1976, and was originally equipped with two Lycoming IO-540-S1A5 engines. On April 24, 1984, at an airplane total time of 1,308.0 hours, the airplane was modified in accordance with Machen STC SA980NW and Machen STC SE978NW, by the installation of a Lycoming TIO-540-J2BD engine and a Lycoming LTIO-540-J2BD engine, along with a Hartzell HC-C3YR-2UF propeller and a HC-C3YR-2LUF propeller. The airplane was further modified at that time with an aerodynamic package, a sound reduction package, an air-conditioning system, an auxiliary fuel tank kit, and a Woodward Propeller Syncrophaser with unfeathering accumulators.

According to a mechanic and a friend of the pilot, on July 7, 1999, during a cross country flight, the airplane experienced a total loss of engine power on the right engine. Additionally, the left engine was unable to maintain manifold pressure, and therefore, the airplane was unable to maintain altitude. When the airplane descended, the pilot was still unable to regain the left engine's lost manifold pressure. According to the mechanic, the pilot landed the airplane in Brady, Texas, and contacted him. The mechanic flew to Brady to examine the airplane. Examination of the right engine revealed that a crack had developed in the turbocharger's exhaust casting, which resulted in the magneto's P-leads melting to the engine's firewall, grounding the magnetos.

On July 8, 1999, the mechanic flew back to Brady to remove the right turbocharger and make a list of required parts to be replaced. Additionally, the mechanic visually inspected and pressure checked the left engine and found the rubber interconnect boot, which routes the induction air between the turbocharger controller elbow and the fuel servo, "gaping open at the connection to the engine's throttle body (fuel servo)."

On July 19, 1999, the mechanic returned to Brady to replace hoses on the right engine and reinstall the left engine's rubber interconnect under its clamp and retighten. On July 20, 1999, the mechanic replaced the right turbocharger, transition assembly, and reinstalled the wastegate and its controller. He also installed new exhaust clamps on the right engine. He then performed a run-up check on both engines. The right engine was run at full power, with all instruments "checked good." The left engine was run at partial power. Both engines were examined visually and "checked good." On July 21, 1999, the pilot was told by the mechanic to do a full power run-up on both engines, and if everything appeared normal, to takeoff, fly around the airport at Brady, and if everything looked good, to fly to San Angelo. The pilot arrived in San Angelo approximately 1730 and said, "it ran very good. Both engines had full power and [the left engine] was better than ever."

On July 22, 1999, the mechanic removed the engine cowlings and visually inspected the engines. He stated that they "checked o.k." The pilot flew the airplane to Oklahoma City, Oklahoma. He called the mechanic at 16:45 and said "he made the trip o.k." He added that the "right engine ran great, but the left engine lost manifold pressure at altitude, and during the descent into Oklahoma City, the manifold pressure started to increase as atmospheric pressure increased." The pilot asked the mechanic if he should fly the airplane back to San Angelo "as is," and the mechanic recommended that the pilot have a mechanic in Oklahoma City examine the airplane.

On July 23, 1999, the pilot called the mechanic at 0910 and said, "a mechanic found hose had slid off again. They reinstalled it and felt sure it was o.k." The pilot informed the mechanic that he was flying to San Angelo so that the mechanic could "look at it and double check everything."

Mechanics, located at the Wiley Post Airport, stated that they told the pilot that they would not be able to examine the airplane for a few weeks, but recommended to the pilot that he leave the airplane at their facility. One of the mechanics in Oklahoma stated that on the morning of the accident, he saw the pilot had the cowling off of the left engine and he appeared to be working on the engine, but did not know what he was working on.

Review of the maintenance records revealed that the last annual inspection was endorsed on April 1, 1999, at an aircraft total time of 2,906.0 hours, and a total time on the e