According to the final report of the Irish Department of Transport Air Accidents Investigation Unit (AAIU) published earlier this year, a Beech King Air 90 (registration N712DB) rolled and dived during an August 2006 flight in Ireland because the owner/pilot lost control of the aircraft during a missed approach in instrument conditions. The pilot’s inexperience was deemed a factor.
Both pilots were Irish. Under U.S. law, only U.S. citizens and legally resident aliens are permitted to own U.S.-registered aircraft. Non-U.S. citizens often set up a company that is the FAA-registered owner and enter an agreement with that company to fly the aircraft. That is the case with the actual owner of N712DB, who was the pilot flying. He held an FAA private pilot certificate with instrument rating and had 753 flying hours, 95 in type. He was relying on the pilot in the right seat, who had 2,000 hours and was familiar with the airplane’s recently installed Garmin GNS 530. The right-seat pilot had an FAA commercial pilot certificate with instrument rating.
The airplane took off from Weston Executive (EIWT) for Ireland West Airport Knock (EIKN). As they approached EIKN the weather was deteriorating and a landing aircraft reported the ceiling at 180 feet. Two minutes later N712DB was cleared to self-position onto the ILS as there was no radar. The right-seat pilot heard this and requested a missed approach with vectors for another ILS. ATC reminded them that there was no radar at EIKN and cleared the aircraft for a procedural missed approach with a right turn back to the OK beacon for an NDB/ILS approach. The crew acknowledged this.
At 15:37:22 they reported beginning a go-around and, answering a request by ATC for their altitude two-and-a-half minutes later, they responded, “N712DB is having trouble.” At 15:41 they reported that they “just ran into trouble with the GPS so er we’re now level at 350, we’re heading north.” When ATC instructed them to maintain 3,000 feet they confirmed that and said they were going back to EIWT.
They did not report the incident to the Irish Aviation Authority (IAA).
Aircraft Exceeded Design Limits
More than a month later, the accident attracted the notice of the IAA when an inspector, making a routine visit to EIWT, found an insurance assessor checking the aircraft for wing damage. Only then was a formal investigation launched. The aircraft owner told AAIU investigators that the crew was heading west in the missed approach at 140 knots with the gear retracted and partial flaps.
He claimed that at about 1,800 feet there was a sudden jolt and the aircraft rolled to the right more than 90 degrees. It did not respond to left aileron input and he allowed the more experienced right-seat pilot to take control. The nonflying pilot chose to continue the roll to the right through to wings level.
As a result of the high power setting and a nose-low attitude, the airplane lost height and its speed increased rapidly. As the aircraft rolled inverted, the artificial horizons toppled and the pilot could see the upper part of the windscreen getting darker as they neared the ground. He maintained control input until the screen became lighter and then he applied full back pressure on the controls to recover from the dive. He thought the maximum speed was between 280 and 300 knots.
The skins on the top wing surface of both wings were buckled at the outer panel joint, with the buckling on the port wing more significant than that on the starboard, consistent with right roll and high gs. Upper skin ripples extending from the joint on both wings were consistent with a gross overspeed as the aerodynamic forces pushed the wings up and aft. Further damage to the horizontal stabilizer due to a heavy pull back at a speed 160 percent more than Vfe supported this theory.
The owner’s pilot certificate was not valid as he had no current FAA medical certificate. In addition, the aircraft was operated in instrument conditions on a VFR flight plan. Turbulence was unlikely to be a causal factor, investigators decided, but on the missed-approach procedure the owner lost situational awareness and control, resulting in the aircraft being rolled in IMC conditions. The right-seat pilot recovered the aircraft from inverted flight but in the process substantially exceeded both flight manual and design limitations.