NTSB Factual Report

On July 13, 2002, at 2155 central daylight time, a Piper PA-28-161 single-engine airplane, N96PF, was destroyed by fire following an in-flight fire during a dark night cross country flight near Purcell, Oklahoma. The instrument rated commercial pilot and the 3 passengers sustained minor injuries. The airplane was owned and operated by a private individual under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the night cross country flight for which a visual flight rules (VFR) flight plan was filed and a weather briefing was received. The flight originated from the McKinney Airport (TKI), near McKinney, Texas, at 2042, with the Wiley Post Airport (PWA), near Oklahoma City, as its intended destination.

The pilot reported that while in cruise flight at 4,500 feet MSL, the right rear passenger of the airplane, a 64-inch tall, 120-pound female, complained to him that her seat was hot and she smelled something like an electrical fire. Upon closer examination of the seat, the passenger noted a glowing hole with a thin line of light from under the seat cushion. About the same time, the pilot noted that the instrument lights dimmed and his radios began to cut out intermittently. The pilot elected to reduce the electrical load as much as practical. After a while, the leather seat cushion started to smoke and the passenger attempted to extinguish the fire with a blanket and bottled water to no avail.

The pilot, who had been receiving traffic advisories from Oklahoma City Approach Control, reported a cabin fire that appeared to have originated from the area under the right rear passenger seat, and declared an emergency. The controller quickly responded with a vector to the Purcell Airport, on a heading of 340 degrees for 8 miles. The pilot turned to the assigned heading and initiated a descent while he switched his standby transmitter to the Purcell frequency. The pilot added that he clicked the radio 5 times on the assigned frequency in an attempt to activate the runway lights at the Purcell Airport; however, he was not able to locate the airport in the darkness. The pilot switched back to approach control and asked if there were any other airports with lighted runways, and was told that both airports were further away.

Smoke filled the cabin and the pilot elected to execute an emergency landing on the northbound lanes of Interstate Highway 35, near Purcell, Oklahoma. The pilot advised approach control of his intentions to land on the northbound lanes. The controller notified the emergency services for the area. The pilot configured the airplane with "one notch of flaps" as he turned on final approach for the interstate. An overpass became visible and the pilot used his excess airspeed to clear the overpass bridge. After clearing the bridge overpass, the pilot extended the flaps to the full down position and reduced the engine power to idle.

The 508-hour pilot managed to avoid vehicles traveling on the highway, touched down on the centerline of the northbound lane and immediately applied maximum braking. As the aircraft began to slow down, the pilot guided the airplane toward the right shoulder of the road to keep vehicular traffic from colliding with the airplane from the rear.

As soon as the airplane came to a complete stop, the pilot guided all of the occupants, a 15-year old female, a 6-year old male, and their mother, out of the burning aircraft and into the shoulder of the roadway. The fire continued to burn out of control until the fuselage and cabin were consumed by the fire. Units of the local fire department arrived within 2 minutes of the emergency landing; however, the airplane was already destroyed.

The wreckage of the airplane was conditionally released to the insurance adjustor for recovery to a secured location. The wreckage was subsequently recovered to Air Salvage of Dallas (ASOD), near Lancaster, Texas.

On July 23, 2002, the wreckage was examined under the supervision of the NTSB investigator-in-charge. Examination of the wreckage revealed that the cabin was mostly destroyed and all combustible material within the cabin was consumed by the fire. The rear seat frame was found loose and laying in the aft portion of the fuselage. The frame did not show a trace of the required 1/2-inch thick plywood or the clamps required to secure the plywood to the seat frame. A broken spring was found in the area above the battery. Additionally, the springs on both sides of the rear seat appeared to be stretched out and sagging. The area around the battery box was manually sorted and three fasteners, identified as the Dzus fasteners used for the battery cover, were found in the immediate vicinity. The investigative group concluded that a battery cover was installed prior to the fire.

The seat frame was then repositioned in the area it normally would have been in flight. The broken spring was noted to be immediately above the positive terminal of the lead acid battery. The positive terminal and associated wiring was removed and viewed under a magnifying glass. Melted material and pit marks were noted on the terminal near the battery wing nut. The negative terminal for the battery showed minimal fire damage or thermal deformation.

A review of the maintenance records for the 1981 model Piper airplane (serial number 28-8116266) revealed that the original Airworthiness Directive (AD), 81-23-05, which was issued on March 8, 1982, to prevent possible in-flight fires, was signed off on February 17, 1982, at 42.7 aircraft hours. This AD and Piper Service Bulletin (SB) 631B require the installation of a 1/2-inch-thick piece of plywood to be installed above the battery to protect the battery terminals from coming in contact with the springs for the passenger seat cushion. The was adequate in raising the awareness and the level of safety; however, did not prevent future risks by not requiring future repetitive inspections. Since that time of the initial AD compliance inspection, the aircraft interior was replaced twice, once on October 8, 1997, at 10,265 aircraft hours, and then again on October 16, 2000, at an undetermined airframe time.

The aircraft was not equipped (or was required to be equipped) with a portable hand-held fire extinguisher.

NTSB Probable Cause

The in-flight cabin fire as result of non-compliance with an AD and a Service Bulletin. A contributing factor to the accident was night conditions.