What happened
On July 21, 2013, at 05:23 AM, a Sukhoi RRJ-95B, registration 970 and 005, was conducting flight certification tests at Keflavik Airport (BIKF). The flight was part of a program to expand the aircraft's capabilities for CAT IIIA automatic approaches. The specific test, number 978, was designed to simulate a critical engine failure at a low radio altitude during a missed approach in crosswind conditions.
During the approach to runway 11, a certification expert intentionally shut down the right engine to simulate the failure. As the aircraft touched down, the automatic throttle disengaged. The pilot flying initiated a go-around procedure by selecting the takeoff/go-around (TOGA) mode; however, the pilot mistakenly advanced the throttle for the inoperative right engine while the left engine remained at an insufficient power setting. After the landing gear was retracted, the aircraft lost airspeed and altitude, eventually striking the runway with its fuselage belly and engine cowlings. The aircraft skidded off the end of the runway, coming to rest 163 meters beyond the threshold of runway 29.
The investigation
The RNSA investigation examined the flight test program, crew duty cycles, and aircraft systems. The investigation established that the flight crew had been on duty for over 10 hours, significantly exceeding the maximum allowed flight test duty time under Russian Federal Aviation Regulations. The investigation also noted that the flight test was being conducted on a runway not authorized for low approaches or touch-and-go maneuvers according to the local Aeronautical Information Publication (AIP).
Furthermore, the investigation looked into the emergency response and evacuation. It was found that the emergency escape slides on the forward right door were not armed prior to the flight, and the crosswind prevented the forward left slide from being usable. The investigation also identified a delay in the activation of the airport's emergency plan by air traffic control personnel.
Findings
- The primary cause of the accident was flight crew fatigue, as the crew had exceeded their permitted duty limits due to significant delays in the flight test schedule.
- The pilot flying advanced the throttle of the inoperative engine during the go-around, which failed to provide sufficient thrust for the climb.
- The automatic throttle disengaged upon touchdown, leaving the operative engine at an insufficient power setting.
- The flight test was being conducted under conditions that exceeded the crew's legal duty time and utilized a runway not authorized for such maneuvers.
- The aircraft sustained extensive structural damage to the aft lower fuselage, engines, and landing gear doors.
- One crew member sustained minor injuries during the evacuation.