CEN18LA349

The fire during approach for reasons that could not be determined based on the available evidence, which resulted in impact with terrain during approach for a precautionary landing.

The pilot stated that he received a generator failure annunciation while en route and decided to return to the departure airport. During the approach, the pilot opened the canopy after severe smoke entered in the cockpit. The pilot stated there was a heavy spray of fuel during the downwind leg of the approach that ignited during the base leg of the approach. During the final leg, when the airplane was about 150-200 ft above ground level, he determined that he could not reach the runway due to the severe fire. He pushed the airplane nose down about 20-25°, and the airplane impacted the ground short of the runway. The airplane was destroyed by impact forces and a postcrash fire. Postaccident examination of a fabric sample from the pilot's flight suit revealed stains that were consistent with hydraulic fluid. Postaccident examination of the airplane revealed the engine was separated from the airframe, and the propeller was separated from the engine. The propeller blades displayed features consistent with engine power. Fire consumed most of the cockpit area and underlying systems between the firewall and aft cockpit. Due to the fire damage, the ignition source and the flammable source could not be determined. The pilot did not perform an emergency shut down of the electrical system and/or engine after the generator failure annunciation as indicated in the airplane flight manual. However, the effect of the pilot not performing the airplane emergency procedures for smoke and fire is unknown because the timing in which the procedures would have to be performed, the flammable source location, and the kind of ignition source are unknown.

On August 23, 2016, at 1106 central daylight time, a North American T-28B, N215SF, experienced an in-flight fire during approach to runway 18 at Anoka County-Blaine Airport (ANE), Minneapolis, Minnesota. Smoke was seen trailing from the airplane before it descended and impacted the ground near the approach end of runway 18. The pilot sustained serious injuries and the airplane was destroyed by impact forces and a post-crash fire. The airplane was registered to Aviation Specialty LLC and was operated by the pilot under 14 Code of Federal Regulations Part 91 as a personal flight that was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The local flight originated from ANE at 1030. A witness stated that he was marshaling an aircraft at a fixed base operator located at the north end of the airport when he saw the T-28 coming in. He said the T-28 entered a "hard left turn," which "seemed standard for them." The airplane "seemed normal" as it was flying downwind and then "cut a little soon" than what he was used to seeing. He said the airplane performed S-turns toward the approach end of the runway, performed a slip and then may have stalled; it "seemed like it stalled." The airplane impacted on the north side of the runway, right wing first, and the airplane cartwheeled. The landing gear was in the extended position when the airplane turned onto the base leg. The engine sounded "normal." The pilot stated while en route, he received a generator failure annunciation and decided to return to ANE. When he entered an overhead approach at ANE, he experienced severe smoke and he then opened the airplane canopy. During the downwind leg, he experienced a heavy spray of fuel. During the base leg, the fuel ignited, and he was engulfed in flames. He entered the final leg and about 150-200 feet above ground level, he determined that he could not attain the runway for landing due to the severe fire. He pushed the airplane nose down about 20-25 degrees and the airplane impacted the ground short of the runway. The pilot submitted a piece of fabric from his flight suit, which had been sprayed with a fluid when the fire occurred, to the National Transportation Safety Board Material Laboratory. An ultraviolet lamp was used to visualize stains on the fabric; several spots were found. The most stained area was examined using a Fourier Transform Infrared spectrometer with a diamond attenuated total reflectance accessory. The spectrum contained a combination of spectral peaks corresponding to particular functional groups consistent with a phosphate ester. Phosphate esters are commonly found in hydraulic fluid. The presence amide was likely due to an additive to the hydraulic fluid. A spectral library search was performed using the residue spectrum. There were no exact matches to a hydraulic fluid, however, the unknown spectrum had several similarities to a few lubricating oils which are spectrally similar. Post-accident examination of the airplane revealed the engine was separated from the airframe, and the propeller was separated from the engine. The propeller blades displayed features consistent with engine power. Fire consumed most the cockpit and the underlying systems between the firewall and aft cockpit. Due to the fire damage, the ignition and flammable sources could not be determined. The T-28 flight manual Landing Gear System description stated that the landing gear is held up by mechanical locks. All the landing gear uplocks are released by initial movement of the landing gear handle; consequently, in event of hydraulic failure, the gear can be unlocked by the gear handle; the main gear extends by its own weight, and the nose gear is extended fully by a spring bungee. The emergency checklist for Generator Failure stated that illumination of the generator-off warning light indicates that the generator is inoperative, and the battery is supplying all the power for the electrical system. In case of a generator failure: 1. Nonessential electrical equipment – OFF. Conserve the battery by immediately turning off all nonessential electrical equipment. If necessary, place dc power switch at OFF and pull circuit breakers. 2. Instrument power – NO. 1 INV. (Unmodified aircraft – NO. 2 INV.) 3. DC power – BAT ONLY (if radios and instruments are needed). If flight can be conduced with instruments but without radios, place the dc power switch at BAT & GEN except when radios are required and before landing. The emergency checklist for Elimination of Smoke or Fuel Fumes was: 1. OXYGEN – 100% (if applicable). 2. Fuel pressure – CHECK. Warning If loss of fuel pressure is evident, refer to fuel pressure drop procedures. 1. Airspeed – Reduce immediately. Reduce airspeed to minimize spreading and to minimize and to prepare for extraction*/bail-out if necessary. 1. Cockpit air – OPEN. 2. Air outlets – OPEN. 3. Windshield and canopy defrost – ON. Warning If smoke or fumes enter cockpit from any outlet, turn cockpit air handle to EMER OFF. 1. All nonessential electrical equipment – OFF. 2. Canopy – OPEN. An open cockpit may aggravate a smoke of fuel fume condition. Open canopy, only a last resort. 3. Land at nearest suitable airfield. The inflight emergency checklists for fire were: Engine Fire, Fuselage Fire, Wing Fire, and Electrical Fire. The Fuselage Fire checklist stated: If fuselage fire occurs during flight, proceed as follows: 1. Check cause by shutting off the following, one at a time: 1. Cockpit heater – OFF. 2. Cockpit air – EMERG. OFF. 1. If fire continues, shutdown the engine and extract* or bail out. 2. If fire is extinguished, land at nearest suitable airfield. The emergency checklist for Electrical Fire stated: Circuit breakers isolate most electrical circuits and automatically interrupt power to prevent a fire when a short circuit occurs. However, if circuit breaker protection does not prevent an electrical fire, and if electrical power is essential (as during instrument flight), try to identify and isolate the defective circuit as follows: 1. Battery and generator – OFF. 2. All electrical equipment (except ignition) – OFF. 3. Battery and generator – Check operation separately. 4. Isolate defective equipment. Turn on each circuit or piece of equipment individually and check load meter for abnormal reading. Allow sufficient time for the indication or reoccurrence of fire when restoring power to each circuit previously turned off. 5. Defective equipment switches – OFF. 6. Land nearest suitable airfield. Following the accident, the pilot submitted the story of his accident flight to the North American Trainer Association publication, Skyline, and to Warbirds of America for publication. The story is included in the docket of this report. Several of the pilot's takeaways and suggestions, based on his perspective and experience of a fast onset of a very severe fire in the cockpit, were: • It is my suggestion that if you have generator failure in flight, or if you have any electrical component fail in flight, or if you sense that anything may be burning in the aircraft, switch all electrical power off immediate and land ASAP. In my case I don't know if the generator failure caused something electrical to short out or if something electrical shorted out and caused the generator to fail. As in my case, you never know what may be smoldering that can turn into a horrible fire. I made the