It was a very nice late June day in 2002 in central North Carolina, where I was a member of a soaring club at a private airfield near Raleigh. I was also one of the club’s tow pilots. I enjoyed flying gliders, but I really enjoyed the challenges of flying the club tow plane, which I had been doing for several years.
The airfield runway (18-36) paved portion is 2459 ft. x 40 ft., and there is a shorter parallel grass runway immediately adjacent and to east of the paved runway that is occasionally used for glider landings and antique aircraft. The runways are sloped, with the high end at the north end of the runways. For glider operations, under light wind conditions such as the day of the incident, takeoffs are usually made downhill on paved runway 18 and landings are made uphill on paved runway 36. The high-end overrun for paved runway 36 is into a farm field that was planted in grass, and there is a short grass overrun at the low end of the paved runway 18. All grass runways and overruns had recently been mowed and the grass and pavement conditions were dry.
The club’s tow plane at the time was a 1964 Cessna 1964 150/150 with a climb-pitch propellor. After checking fuel, and doing a preflight inspection, the aircraft appeared to be airworthy. I taxied to runway 18, where a waiting glider was attached to the towrope, and at approximately 1248 EDT, I took off with one notch of flaps, downhill on runway 18 with the glider in tow. Winds were light and variable, but mostly from the southwest.
The tow proceeded well and without incident at the normal tow speed of about 65 mph. There was strong lift that day and the glider released from the towrope about one and a half miles southeast of the airfield, at 2500 ft. AGL. I was keeping track of time and altitude of tows using a portable GPS that was powered by the accessory outlet. After the glider released, a standard procedure steep left turn was made back toward the airfield, carburetor heat was applied, power was reduced to about 1900 rpm, and full flaps were applied. I put the aircraft into a left slip and descended at approximately 1600 fpm to return to the airfield pattern to pick up the next glider, which was waiting on the threshold of runway 18.
Upon arriving at the airfield, the towplane was still too high to make a normal pattern entry, so I raised the flaps, turned off carburetor heat, increased throttle to 2500 rpm and crossed the airfield at midfield. At approximately 1000 feet AGL, I entered a left crosswind to begin the pattern for an uphill landing on runway 36. During the crosswind leg, I noticed an odor in the aircraft cockpit that smelled like hot plastic. During entry into the left downwind leg for runway 36, the plastic odor became much stronger. I turned off all aircraft-powered electrical equipment, including the radio and transponder. I abbreviated my pattern slightly and turned left base early, and descended to about 900 ft. AGL, adding 10 degrees of flaps.
On downwind I checked to make sure the two gliders that were aloft were not in the landing pattern and that no other aircraft were in the vicinity of the airfield. I did not turn off the master switch at that time. I reduced the engine power setting at the time to about 1500 rpm. I do not recall whether I applied carburetor heat at that point, although I normally would have done so. While turning onto left base for runway 36 and adding another notch of flaps, wisps of smoke were emerging from behind the instrument panel on the passenger side, forward of where the doorless glove box opening was located. There was no liner behind the glove box opening, so the area to the rear of the panel behind the opening was visible and it was clear that there was a small electrical fire developing.
By the time the halfway point of the base leg for runway 36 was reached, flames about 4-6” in diameter were visible through the glove box opening, although the fire was not burning intensely at that point. Seconds later, acrid dense black smoke and larger flames were rapidly developing from a point adjacent to the inside of the starboard exterior skin of the airplane about 4-6” forward of the glove box opening. Abbreviating my landing pattern further by turning directly toward the threshold of 36, power was increased to increase airspeed. While turning onto final for runway 36, the flames were out of the glovebox and into the right side of the cockpit seating area, burning very vigorously and much larger.
The dense black smoke was increasing in volume and filling the cockpit, making it difficult to breathe and see. I increased flaps to full 40 degrees and adjusted the throttle to full power to speed up the aircraft despite the flaps—I was not concerned about damage to the aircraft at that point. I then put the aircraft into a nose-down hard left slip to lose altitude more quickly and put the flames on the negative pressure side of the aircraft. Due to the density of the smoke in the cockpit, it was not possible to see whether the fire was also outside the aircraft or just inside, but due to the intensity and heat of the fire, the aluminum aircraft skin may also have been on fire.
It was becoming increasingly difficult and irritating to breathe, so I opened the pilot side window to admit fresh air. Opening the window no doubt added some oxygen to the fire, but it enabled me to breathe and cleared some of the smoke from the cockpit, making it easier to see out of the windshield.
Nearing the runway threshold, it was possible to see well enough through the smoke to observe that the angle of descent was too steep and that the nose of the aircraft needed to be raised or I would crash on the approach end of the runway. I raised the nose and because I was then over the runway threshold, I simultaneously pulled power to idle. As I did this, the aircraft ballooned slightly due to my airspeed. Reduced visibility from smoke in the aircraft cockpit made it difficult to properly judge the attitude and altitude of the aircraft. The cockpit was full of dense black smoke at that point, and breathing was difficult despite the open window. Flames were also increasing in the cockpit of the aircraft from under the right side of the instrument panel and through the glove box opening on the passenger side.
In a slight crab in ground effect to slow the aircraft down at touch-down, I did not know how fast I was traveling but did not want to endanger the glider and crew waiting for pickup on the threshold of runway 18. The aircraft was still in a slight crab and traveling faster than normal for landing, so when it touched down, the aircraft swerved right and exited the paved runway onto the adjacent parallel grass runway immediately to the east of 36. The aircraft was traveling quite fast (the airspeed indicator was not visible due to smoke), but the speed was rapidly decelerating due to full flaps and no power. I was able to control the aircraft back to the left and onto the pavement with left rudder and applied full brakes once on the pavement.
The aircraft speed slowed further, and I exited the runway under full control onto the grass parking ramp area just to the west side of 36 and came to a full stop. Holding my breath to avoid choking on the dense black smoke that had filled the cockpit, I turned off the mixture, the master switch and the ignition key by feel rather than sight. I opened the left door, leaned out and took a breath of fresh air while unlatching my safety harness and then exited the aircraft. The aircraft engine had ceased operating when I turned the ignition switch off, and the propeller was not turning when I exited the aircraft.
After stepping out of the aircraft, I held my breath, and reached in and grabbed my battery-powered portable GPS unit and then moved rapidly away from the aircraft to try to clear my lungs with some fresh air while far enough from the aircraft to be out of danger. I called out to the waiting glider crew that there was a fire onboard the tow plane and I ran to get the nearby water hose. By that time, the smoke had turned to a dark gray color and was pouring out of the open cockpit door and window, enveloping the exterior of the aircraft forward of the wings. The chief of the local fire department, who was at the airfield servicing his own aircraft, responded immediately with two 15 lb. ABC chemical fire extinguishers and called the fire department using his fire department portable radio. My GPS indicated that the total duration of the flight was just under 12 minutes.
The chief emptied one extinguisher into the cockpit through the open pilot side door, but the fire was still burning with dense smoke and a small grass fire had developed under the aircraft from burning debris that was falling from the aircraft. We pulled the aircraft about 20 feet to the rear using the towrope that was still attached to the tow hook and we used the hose from the airport clubhouse to put out the grass fire. The local Fire Department arrived shortly in a pumper truck while the chief and the other members of the soaring club were using the second fire extinguisher to continue to attempt to put out the fire. The fire had abated but was still burning. The fire department completed extinguishing the fire with a large amount of water and treated me with oxygen for smoke inhalation.
The cockpit of the aircraft was destroyed by the fire, including the instrument panel, and at the point of ignition the fire burned an eight-inch diameter hole in the right side of the fuselage forward of the instrument panel (and just forward of the fuel line, which comes down in the right windshield post to the engine from the wing fuel tank). Interior plastics, including avionics and fabric, were either melted or charred. Paint on the exterior left side of the fuselage behind the firewall was blistered and discolored due to heat and smoke. All windows in the aircraft were melted, discolored and crazed from heat, smoke and flames. We tied the aircraft down about fifty feet from the burn site and secured it for inspection by the FAA and NTSB.
What was the cause? Because of the heavy larger engine installation for use as a towplane, the battery had been moved at that time to the rear of the aircraft to maintain weight and balance. The wire that caught on fire was a cable to the accessory plug which bypassed the master switch. The GPS unit probably overloaded the circuit. There is now an AD that requires the accessory plug on 150s to have a fuse or be disconnected.
After the fire, a check of the NTSB database for general aviation in-flight cockpit fires showed that of the approximately 36,000 general aviation accidents and incidents in the database at that time, there were only 36 in-flight cockpit fires listed, including mine. Of the 36, approximately half ended in at least one fatality and approximately half of the other 50% ended in serious or minor injury. Other than a bit of singed hair on my right arm and some smoke inhalation, my incident was in the 25% with no injury or death.
The conclusion from the statistics is that the odds of having an in-flight cockpit fire in general aviation aircraft are small, but if one does happen the odds of being injured or killed are pretty high. Lessons learned from this incident include that it is important not to panic in an emergency and that one should always carry a fire extinguisher when flying even small aircraft.