The decision to continue an unstable approach despite several indications of problems played a central role in the March 2016 accident involving a Mitsubishi MU-2B at Îles-de-la-Madeleine in Quebec, Canada's Transportation Safety Board (TSB) found. All seven occupants, including the two pilots, were killed.
According to the TSB, the problems started in cruise when the pilot modified his approach plan to begin the descent later, partially to save fuel. This led to higher-than-recommended approach speeds and altitudes for the published approach. Reported weather conditions at the airport included a broken cloud layer at 200 feet agl—lower than the published minimum descent altitude. The pilots never discussed this.
Soon after crossing a fix that called for a turn to intercept the runway centerline, the aircraft—flying 1,500 feet above the 3,000-foot recommended altitude and nearly 100 knots faster than the 140-knot approach speed—soon began "a meandering flight path," TSB wrote in its final report. "The pilot’s workload had increased significantly," and neither the approach nor before-landing checklists were done.
At about 1.5 nm from the airfield and flying at near stall speed to lose altitude, the pilot added full power. This led to an upset and rapid descent. "There was insufficient altitude to recover the aircraft," TSB wrote. The aircraft struck the ground 1.4 nm west of the airfield.
"At no time during the approach did the pilot discuss discontinuing the approach as an option available to reduce the workload," the TSB wrote. Its probe was aided by an onboard flight recorder, which was not required equipment.
Unstable approaches are one of three aviation-specific items on the TSB's Watchlist of key safety issues. Runway overruns and runway collision risks are the other two.
The decision to continue an unstable approach despite numerous warning signs played a central role in the March 2016 accident involving a Mitsubishi MU-2 at Îles-de-la-Madeleine in Quebec (YGR), Canada's Transportation Safety Board (TSB) found. Both pilots and all five passengers, including former Canadian minister of transport Jean Lapierre, were killed.
TSB's final report revealed that the problems started en route from Montréal/Saint-Hubert Airport (YHU) when the pilot, looking to save fuel, modified his approach plan to "delay" his descent into YGR. This necessitated using higher-than-recommended approach speeds and descent altitudes.
The pilot chose the RNAV/GNSS approach to YGR's Runway 7. The approach's minimum descent altitude (MDA) is 620 feet msl/598 feet agl. A localizer/distance measuring equipment (LOC/DME) approach with a 480-foot msl MDA was also available.
"The pilot stated that he preferred the RNAV (GNSS) approach because the autopilot system can remain coupled for the descent and approach," the TSB wrote. "However, the pilot advised the passenger-pilot that, if the ceiling was below the RNAV (GNSS) MDA, he could easily switch to the LOC/DME approach and continue to the lower MDA."
Reported weather conditions at YGR included a broken cloud layer at 200 feet agl, well below each approach's MDA. The pilots never discussed this, the TSB found.
After crossing a fix that called for a turn to intercept the runway centerline, the aircraft—1,500 feet above the 3,000-foot msl recommended altitude and nearly 100 knots faster than the 140-knot approach speed—soon began "a meandering flight path," the TSB wrote. "The pilot’s workload had increased significantly," and neither the approach nor before-landing checklists were done, the report said.
At about 1.5 nm from the runway and having slowed to near-stall speed to lose altitude, the pilot added full power. This caused "a power-induced upset and resulted in the aircraft rolling sharply to the right and descending rapidly," TSB wrote. "There was insufficient altitude to recover the aircraft."
The MU-2 struck the ground 1.4 nm west of the airport.
The pilot flying had 2,500 total hours, including 125 in MU-2s. He had a Canadian airline transport pilot license, an FAA private pilot license, and had completed all required training to operate a U.S.-registered MU-2. The MU-2 involved in the accident was based at Saint-Hubert Airpor (YHU) but carried a U.S. registration.
Investigators determined that the passenger-pilot was licensed but "had no experience on the occurrence aircraft type and was not assigned any specific flying duties," the TSB wrote. His lack of familiarity with the MU-2 contributed to the flight deck workload, investigators found.
For instance, during the approach, the pilot asked the passenger-pilot to contact the YGR flight service station for a weather report. "The pilot spent the next 40 seconds explaining to the passenger-pilot how to select the correct frequency on the second radio and how to operate the radio," the TSB wrote. "At no time during the approach did the pilot discuss discontinuing the approach as an option available to reduce the workload."
TSB's probe was aided by data recovered from a Wi-Flight GTA02 flight data recorder, which captured 13 parameters and ambient cockpit sound.