April 30, 2020

Instrument Failure Led to King Air Crash


The Transportation Safety Board (TSB) this week released its investigation report into the January 30, 2019 Air Tindi crash of a Beechcraft King Air near Whatì, Northwest Territories that claimed the lives of both pilots.

The flight, with only a two-man crew on board, departed Yellowknife airport (CYZF) in the morning bound for Whatì airport (CEM3), normally a 36-minute flight at a planned altitude of 12,000 feet ASL. Shortly after initiating descent, the pilot’s attitude indicator failed, and the autopilot automatically disengaged. The left seat pilot, the captain, took manual control using partial (instrument) panel piloting techniques as they were at that moment in instrument meteorological conditions (IMC). The captain began a climb but was unsuccessful as the twin-turboprop aircraft began to descend again. Seconds later the aircraft began first a right turn, then a left turn, all the while descending at progressively greater airspeeds. The aircraft then continued into a spiral dive and impacted terrain at an estimated airspeed of 404 knots. The 406 ELT was activated.

The flight had departed with the co-pilot’s vacuum-driven attitude indicator inoperative. Although the aircraft’s minimum equipment list (MEL) permitted the aircraft to depart with only one attitude indicator, certain conditions for doing so had to have been met. The following is an excerpt from Air Tindi’s MEL for the occurrence aircraft that specifies exceptions to the MEL:

[The gyroscopic pitch and bank indicator] may be inoperative on right side provided:
(a)  A second in command is not required for the flight.
(b)  Aircraft is not equipped with EFIS or Survoed Electric Gyroscopic Pitch and Bank Indicator
NOTE: Where a served electric altimeter is installed, a functioning pneumatic indicator is required.

The King Air involved in the crash was equipped on the left (pilot) side with an electrical attitude indicator, in non-conformance with the MEL.

The aircraft was equipped with a cockpit voice recorder (CVR), which allowed the TSB investigators more insight into how and why the flight proceeded.

According to a press release issued on April 27 by the TSB, “The investigation determined that the crew did not effectively manage and mitigate the risk associated with the unserviceable right-side attitude indicator. Crew resource management was also not effective and resulted in a breakdown in verbal communication, loss of situation awareness, and the aircraft entering an unsafe condition.”

The complete TSB report is appended below.

Image credit: TSB