ATL95FA007

Maintenance had been performed on the engine turbo-chargers & exhaust systems several days before the accident flight. After departure, the pilot reported that the left engine lost power & he elected to return to the airport. A witness reported seeing the airplane heading toward the airport with an orange glow under the left wing about four feet outboard of the fuselage. The witness said there was a loud pop, the left wing separated from the airplane, & the plane fell to the ground. Inspection revealed extensive fire damage in the area of the left wheel well & spar, behind the firewall, immediately aft of the turbo-charger exhaust. Fuel lines in the wheel well area had burned away. The left engine turbocharger tail pipe & marmon connector clamp were missing. The engines had been equipped with airesearch turbochargers in accordance with STC SA909WE.

History of flight

On October 23, 1994, about 1503 central daylight time, a Piper PA-23-250, N999BW, was destroyed following an in-flight fire, subsequent in-flight breakup, and collision with terrain near Newville, Alabama. Both the commercial pilot, and his passenger were fatally injured in the accident. The aircraft was being operated under the provisions of 14 CFR Part 91 by the pilot. Visual meteorological conditions existed, and no flight plan had been filed for the personal flight. The flight departed Dothan, Alabama, enroute to Jonesboro, Georgia about 1445.

The pilot of N999BW contacted Cairns Approach Control after departing Dothan, advised that he was climbing through 4000 feet, and asked for visual flight rules flight following to South Expressway Airport in Jonesboro, Georgia. About two minutes later, the pilot informed Cairns that he had an engine failure on his left engine and was returning to Dothan. The pilot, when asked by Cairns, did not wish to declare an emergency, and did not wish to have the fire and rescue vehicles standing by at Dothan. The aircraft disappeared from radar about 8 miles northeast of Dothan, and was last observed on radar at 2800 feet.

A witness in the accident area stated that he observed the aircraft flying about 3000 feet on a heading towards Dothan. The witness stated that there was an orange glow coming from an area just outboard of the fuselage on the left wing. He observed the glow become larger, then heard a loud pop, and the left wing separated from the aircraft.

Personnel information

The pilot held a commercial pilot certificate with airplane single engine land, multi engine land, and instrument airplane ratings. He held a flight instructor certificate with airplane single, multi engine, and instrument airplane ratings. He held a second class medical certificate with no waivers or limitations.

Additional personnel information may be obtained on page 3 of this report under the section titled First Pilot Information.

Aircraft information

The Piper Pa-23-250 (Aztec) is a six passenger, low wing, retractable gear, twin engine airplane.

N999BW had turbo-chargers installed on the engines. These turbo-chargers were installed by Piper Aircraft Company, during the construction of the aircraft, under supplemental type certificate numbers SE22WE and SA909WE.

The supplemental type certificate allows for the installation of Airesearch Turbo-charger Kits, Models P202 and P202-1, on the PA- 23-250. The kit consists of the turbocharger, controller, oil tank, exhaust system, and various hoses, clamps, and brackets for the installation.

The turbo-charger oil tank is of aluminum construction with a stainless steel sheet attached to the back for use as a firewall extension. The tank has a plastic oil sight line for oil level determination, located behind the firewall extension. The entrance and exit hole areas, through the firewall, for the oil sight line in the tank (cutouts approximately two inches in diameter) are not protected by the stainless steel firewall extension.

The turbocharger is mounted on the engine, and the exhaust exit for the turbo-charger is approximately four inches in front of the oil tank. According to the manufacturer, the exhaust gas temperature of the turbine is approximately 1,800 degrees. The turbocharger exhaust is connected to the turbine discharge duct tail pipe by use of a marmon clamp. The other end of the discharge duct tail pipe is slip jointed to the exhaust stack and plumbed from the waste gate split.

The marmon clamp is designed to connect the flange end of the turbine exhaust to the flange end of the duct tail pipe. The clamp is circular with a "U" shaped groove in the center. The clamp fits over the flanges and is tightened by use of a bolt, which is tightened to the proper torque and safety wired.

Meteorological information

Visual meteorological conditions existed at the time of the accident.

Additional meteorological information may be obtained in this report on page 3 under the section titled Weather Information.

Wreckage and impact information

The aircraft wreckage was distributed over an area approximately one half mile in length, on a heading of about 210 degrees. The first piece of wreckage in the wreckage path was the outboard section of the left wing, from the engine mount attach point to the wing tip. The left engine and propeller, were found approximately one fourth of a mile in the direction of distribution from the left wing section. The main wreckage, which consisted of the remainder of the aircraft, was found approximately one half mile from the left wing section in the direction of distribution.

Examination of the aircraft wreckage revealed evidence of in- flight fire, directly aft of the turbo-charger exhaust and turbo- charger oil tank, in the area of the left wheel well and spar. The aircraft left engine turbo charger tail pipe and marmon clamp were missing. The left turbo charger aluminum oil tank top half was burned away, and the stainless steel rear fire wall portion of the tank assembly had a hole approximately two inches in diameter open to the landing gear wheel well area. The left main tire and wheel were missing, and there was extensive fire damage to the left main landing gear strut support assembly. The fuel lines from the fuel tank to the engine, which are located in the wheel well, had been burned away.

There was continuity of the engine drive trains. Examination of the turbo-chargers revealed that the turbines rotated freely, and there was rotational scratching in the turbine housings.

Medical and pathological information

An autopsy of the pilot was performed on October 24, 1994 by Dr. Alfredo A. Paredes of the State of Alabama Department of Forensic Sciences.

A toxicological examination was performed by Dr. Barry Levine of the Department of Defense Armed Forces Institute of Pathology. The toxicological report was negative for the use of drugs and alcohol.

Tests and research

Research of the aircraft history revealed that the aircraft was purchased by the present owner in July of 1994. At the time of the purchase, the turbo-chargers were not operating. The aircraft underwent an annual inspection by Wiregrass Airplane Company in Florala, Alabama, and the inspection was completed on September 28, 1994. The turbo-chargers were removed, overhauled, and replaced during the annual inspection. The engine exhaust system was also repaired during the annual inspection.

After the annual inspection, the engines were not producing sufficient manifold pressure at high altitudes. The aircraft was returned to Wiregrass Airplane Company for repair. The turbo- charger controllers were adjusted to attempt to compensate for the low manifold pressure at altitude.

The turbo-chargers were still not producing sufficient manifold pressure, and the aircraft was taken to Dothan Jet Center in Dothan, Alabama on October 11, and 20, 1994 for trouble shooting and repair. The aircraft exhaust system was removed and cracks were repaired. The turbo-charger controllers were found to be incorrectly adjusted, but were not readjusted at the request of the owner.

The Federal Aviation Administration regulations 14 CFR Part 23, Subpart E, Paragraph 23.1191 states that each engine must be isolated from the rest of the airplane by firewalls, shrouds, or other equivalent means. The firewall must be constructed so that no hazardous quantity of liquid, gas, or flame can pass from the isolated compartment to other parts of the airplane and each opening in the firewall must be sealed with close fitting, fireproof grommets, bushings, or firewall fittings.

Additional information

The aircraft wreckage was released to Mr. Harry Brooks, the owners insurance representative, on May 18, 1995.