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| Title: | Crash at airshow, Lockheed P-38J Lightning, N3145X |
| Micro summary: | This Lockheed P-38J Lightning rolled and crashed while executing a maneuver at an airshow. |
| Event Time: | 1996-07-14 at 1451 UTC |
| File Name: | 1996-07-14-UK.pdf |
| Publishing Agency: | Aircraft Accident Investigation Board (AAIB) |
| Publishing Country: | United Kingdom |
| Report number: | EW/C96/7/4 |
| Pages: | 8 |
| Site of event: | Duxford Airfield, Cambridgeshire |
| Departure: | Duxford Airport, Duxford, England |
| Destination: | Duxford Airport, Duxford, England |
| Airplane Type(s): | Lockheed P-38J Lightning |
| Flight Phase: | Cruise |
| Registration(s): | N3145X |
| Operator(s): | Private |
| Type of flight: | Revenue |
| Occupants: | 1 |
| Fatalities: | 1 |
| Serious Injuries: | 0 |
| Minor/Non-Injured: | 0 |
| Other Injuries: | 0 |
| Executive Summary: | The aircraft was performing at the 'Flying Legends' Air Display at Duxford, which was being staged over the two days of the weekend of 13/14 July 1996. The display on 13 July was completed without incident. On 14 July, the aircraft had taken off at 1435 hrs as the lead aircraft in a formation comprising one Curtiss P-40B Tomahawk and one Bell P-63 King Cobra fighter aircraft. The display 'slot' commenced at 1439 hrs and after several formation passes in front of the assembly of spectators, the trio split up in order to enable each aircraft to carry out a solo display. The P-38 was the final aircraft to perform its solo routine and was due to clear the display area by 1455 hrs. The aircraft commenced its run in from the east of the airfield, in a shallow dive to gain speed, then carried out a loop. This manoeuvre was followed by a 'Cuban Eight' manoeuvre, which involved two short periods of flight under negative 'g'. As the aircraft returned to normal positive 'g' flight after each of these periods, a slight trail of light coloured vapour was noted coming from under the main body of the aircraft (post-accident consideration of the aircraft systems concluded that this was most likely to have been vapour escaping from the fuel tank vent lines). At the end of the 'Cuban Eight', the aircraft was passing from east to west (crowd left to right). It pulled up and to the left initially, levelled the wings, then performed a 270° roll to the left. The aircraft then came back to pass across the front of the crowd from west to east. With the aircraft appearing to be at a normal entry height and speed, an aileron roll to the left was commenced as the aircraft crossed the western threshold of the hard surfaced Runway 06. The first 360° roll was completed apparently normally but the aircraft continued, without pause, into a second full roll. While the aircraft was inverted in this second roll, the nose pitched towards the ground and the aircraft began to lose height while the roll continued. By the time the aircraft became upright again, it had descended to a very low height above the runway. The aircraft continued to roll left and struck the runway with its left wing, with some 30° of left bank applied, about two thirds of the way along Runway 06. The left outer wing ruptured and collapsed, followed by an impact of the left engine. At this time, a large fireball erupted as the aircraft began to cartwheel across the airfield, breaking up into multiple fragments as its trajectory took it diagonally away from the main spectator area towards a row of parked light aircraft on the south side of the airfield. Several of these aircraft were destroyed or severely damaged in the wreckage's path. One of the engines bounced further than the rest of the wreckage, crossing the airfield boundary and then the M11 Motorway which runs almost perpendicular to the end of the runway. A passing freight truck sustained some minor damage from pieces of wreckage but was able to continue travelling northwards along the motorway. The engine came to rest in a field just to the east side of the motorway, close to where several members of the public had been standing in order to watch the flying activities from outside the airfield boundary. The airfield Fire and Rescue services were quickly at the scene and brought the numerous areas of fire under control in a short time. The pilot was found in the seat, with his four point harness still fastened, amongst the wreckage of the main fuselage pod. A post-mortem examination found that the pilot had been killed by a severe head injury. No physical condition was found which could have caused any incapacitation of the pilot and no traces of drugs nor alcohol were found to be present. It was assessed that the destruction of the cockpit was such that survival was impossible. The pilots and passengers of the visiting light aircraft had been required, by the airport operator, to move to the spectator side of the runway in order to watch the air display. Fortunately, there were no injuries to any spectators. The display routine followed by the P-38 formation was identical to that flown at the display on the day prior to the accident. The significant difference was that during the Saturday display, only a single 360° aileron roll had been carried out, but at the time of the accident two consecutive 360° rolls had occurred, with a continuation past the wings level at the end of the second roll. Soon after the accident, the air display organisers made an announcement over the public address system for any spectators who had photographed, or taken video footage of, the final manoeuvre to hand in their films/tapes on loan for the purposes of this investigation. An excellent response was forthcoming, which resulted in AAIB having access to some 60 video tapes and 40 sets of photographs of the event. The weather at the time was a surface wind from 270° at 6kt, variable in direction between 240° and 300°, visibility in excess of 10 km, scattered cloud base 3,000 feet, QNH 1026mb. Photographs and video coverage of the aircraft's manoeuvres were analysed with a view to assessing not only the pre-impact flightpath characteristics but also the pre-impact aircraft integrity and the operation of aircraft systems. A full flight path analysis was carried out using several video sequences which had been filmed from a variety of viewpoints. A recording was available of the Saturday display, where one aileron roll to the left was performed. The time taken to complete the roll on this occasion was 3.4 seconds and it was noted that the aircraft had an upward trajectory throughout this manoeuvre. The analysis of the accident coverage showed that the aircraft had performed two continuous aileron rolls, taking 4.4 seconds and 3.6 seconds respectively to complete. This had been started at a height of about 250 feet above the runway, at a speed of about 250 knots and with an initial nose-up pitch attitude. The roll, to the left, was initiated by a rapid roll control input to produce a considerable aileron deflection. This aileron deflection remained more or less constant until the aircraft had completed about 675° of roll. At that point, the ailerons were returned to the neutral position where they remained until the aircraft struck the ground. During the first roll the aircraft climbed to an apogee of about 360 feet when inverted, descending to about 260 feet by the time it was erect again. At this point the aircraft pitch attitude was approximately horizontal or very slightly nose-down. There was no pause before the second roll was executed. During this roll, the nose dropped progressively and an increasing rate of descent built up. At the inverted position the aileron position was observed to be being maintained in the almost fully (left roll) deflected position and a considerable elevator displacement in the 'stick back' sense was made. Considerable left rudder control was also added at this time and the roll rate increased. About 45° of roll before the aircraft became erect, the rudder and aileron inputs were moved to neutral, but were not applied in opposition to the roll. The rate of roll was seen to increase slightly as the aircraft rolled through wings level (from about 110°/sec to 125°/sec), with a rate of descent of about 7,200 feet per minute, to the point of impact. Ground speed at impact was assessed as 230 kt. The final angle of descent was 14.5°, giving a speed along the flight path of 238 kt. Impact was seen to occur on the left wing tip at an attitude of about 30° left roll with the fuselage level in pitch. The aileron and rudder positions were approximately neutral and the elevator was deflected up. An analysis of the propeller speeds from video showed that they remained constant throughout the rolling manoeuvre. Both propellers were turning at about 1,300 RPM, the right slightly faster than the left. With the engine propeller reduction gearing ratio of 2:1, this accorded with the aircraft operating limitations which quoted the engine limits for use in aerobatic manoeuvres as 2,600 RPM/40 inches manifold pressure. It was also noted on the video coverage that the coolant radiator exit flaps were not symmetric for each engine. Those for the left engine were noted to be fully open, while those for the right engine were in trail, for a large part of the final display sequence. Correct engine operation during the manoeuvres was assessed by other means and any possible effect of the asymmetry on the handling of the aircraft was not considered to be significant. |
| Learning Keywords: | Operations - Uncontrolled Flight into Terrain |
| Consequence - Hull Loss |
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