Bend, OR, USA
N166PD
Lancair LC41
The pilot, who had been conducting a series of spin entry and recovery tests, had intentionally entered a spin while applying left rudder and left aft stick. Because his flight control inputs did not result in recovery from the spin after three and one-half turns, he deployed the spin recovery/stabilization drogue parachute. Once the aircraft was established in an attitude from which the pilot could maintain controlled flight once the parachute was released, he pulled the drogue chute manual jettison handle. At that point, because the chute did not release, the pilot activated the electrical backup jettison system. When that action did not release the parachute, the pilot tried the electrical system a second time, and finding that this action did not release the chute, he tried the manual release a second time. At that point, because the parachute still remained attached, the pilot applied engine power in an attempt to establish controlled flight with the parachute in trail. Once he determined that the aircraft could not be satisfactorily flown in that configuration, he exited the aircraft and deployed his emergency parachute. During the investigation it was determined that the drogue chute either became entangled in the drogue chute tail boom after release from the tow hook mechanism, or it did not release from the tow hook mechanism when the pilot tried to activate it, but instead was released by the forces created by the impact with the terrain. It was also determined that the chute release system was not flight-load tested on this specific aircraft prior to the in-flight activation. Furthermore it was determined that the backup electrically activated cable guillotine system was wired incorrectly, and could not have been activated by the pilot in flight.
On August 27, 2003, approximately 1045 Pacific daylight time, a Lancair LC41, N166PD, impacted the terrain about 15 miles east of Bend, Oregon. The commercial pilot, who had parachuted from the aircraft inflight, was not injured, but the aircraft, which was owned and operated by The Lancair Company, was destroyed by the impact sequence and subsequent fire. The 14 CFR Part 91 pre-production test flight was being conducted in visual meteorological conditions. The aircraft departed Bend Municipal Airport at 1017. No flight plan had been filed. There was no report of an ELT activation. According to the pilot, he had been conducting a series of spin entry and recovery tests, and had intentionally entered a spin while applying left rudder and left aft stick. Because his flight control inputs did not result in recovery from the spin after three and one-half turns, he deployed the spin recovery/stabilization drogue parachute. Once the aircraft was established in an attitude from which the pilot could maintain controlled flight once the parachute was released, he pulled the drogue chute manual jettison handle. At that point, because the chute did not release, the pilot activated the electrical backup jettison system. When that action did not release the parachute, the pilot tried the electrical system a second time, and finding that this action did not release the chute, he tried the manual release a second time. At that point, because the parachute still remained attached, the pilot applied engine power in an attempt to establish controlled flight with the parachute in trail. Once he determined that the aircraft could not be satisfactorily flown in that configuration, he exited the aircraft and deployed his emergency parachute. The aircraft eventually impacted the terrain and caught on fire. The unburned and undamaged drogue parachute, along with the chute lead, lead attach ring, and electrical cable cutting guillotine assembly was found about 30 feet from the aircraft. Although the spin recovery chute lead attach ring was found released from the Yost Type E-85 mechanical release mechanism, it could not be determined if that release took place when the pilot pulled the spin chute jettison handle in flight, or whether it separated at the moment the aircraft impacted the terrain. Due to the way the E-85 is constructed and mounted on the aircraft, it is possible that upon impact with the ground, the release lever on the front of the unit rotated forward, thereby releasing the chute attach ring. An inspection of the mechanical release system revealed scarring on the boom that could have been created by the lead and ring becoming entangled in the boom after an airborne release from the Yost E-85, but it was determined that the same scarring could have occurred if the lead and ring impacted the boom as it was released at the moment of impact with the terrain. According to Lancair, the spin chute deployment and jettison system had been installed on the earlier "non-conforming" 40001 aircraft, and then the mechanical portion was tested for chute jettison functionality under load. During those tests, the mechanical release system was successfully operated from the cockpit with lateral and vertical loads of 200 pounds, and a parallel/inline load of 750 pounds. When the system was installed in the subject 41001 aircraft, the system did not undergo static load testing as it had on the previous aircraft. Instead, the testing of the mechanical release system was limited to connecting a parachute lead O-ring to the release mechanism, applying a medium "hand-applied" pull on the lead, and then pulling the cockpit-mounted jettison system D-handle to make sure that the release mechanism on the boom released the O-ring. This test confirmed the release of the O-ring, and confirmed there was no unusual pull resistance under the defined conditions. It was also determined that for the installation in the previous model, a hole was drilled in an existing bulkhead so that the cable housing from the D-ring to the release mechanism could run in a relatively straight line. According to Lancair, on the accident aircraft, the cable housing was run through an existing hole, which changed its alignment from the installation in the previous model. No tests were run on the 41001 aircraft to ensure that with the new routing of the cable the mechanism would function properly under expected flight loads. During the post-accident inspection of the release system, there was an attempt to activate the backup electrically-initiated pyrotechnic cable cutting guillotine, but the system did not activate as expected. It was ultimately determined that the initiation unit had been wired incorrectly and therefore could not have been activated from the cockpit switch. According to Lancair, the original cable cutter the company purchased had two wires emanating from the base of the activation unit, and its wiring setup was therefore intrinsically obvious. But the unit that was installed on the accident aircraft had two white wires and two black wires coming out of the activation unit. Therefore the manufacturer of the device was contacted by phone and the correct wiring discussed. Somehow the individual involved in that call came away from that conversation with the mistaken understanding that both black wires were the ground leads and the white wires were to be connected to the positive power source. This was an incorrect understanding, as the white wires were the leads for one activation circuit and the black wires were the leads for a second. According to the personnel who were assembling the system, because of this misunderstanding, and the fact that there was at that time no activation unit wiring diagram at Lancair, the system was wired so that both white wires received +12 DC volts, and both black wires were attached to a common ground. After discovering the incorrect wiring setup in the post-accident inspection, power was applied across one of the same-color circuits (white to white or black to black), and the unit functioned as expected. Lancair further stated that, although an original style two-wire cable cutting unit had been explosively tested prior to the installation of a like unit on an aircraft, the testing on the subject dual-wired unit was limited to a continuity check of the wiring from the activation switch to where the circuit from the aircraft plugged into the circuits on the activation device.
The inadequate design of the drogue chute mechanical jettison system, which resulted in its failure to separate from the aircraft during in-flight spin recovery tests, and the incorrectly wired drogue chute cable cutter activation unit, which resulted in the inability of the pilot to activate the backup chute separation system after any failure of the primary system.
Source: NTSB Aviation Accident Database
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