The Icelandic Transportation Safety Board published the final report of the investigation into a serious incident in which an Icelandair Boeing 757 made an uncommanded left roll during final approach.
On 26 February 2013 a Boeing 757-200 airplane (TF-FIJ) operated by Icelandair was flying from Copenhagen-Kastrup Airport in Denmark to Keflavik Airport in Iceland with 171 persons on board.
At 22:26 at night the aircraft was on a 7 NM final approach to runway 20 at Keflavik Airport. When the flaps had been fully deployed the airplane suddenly rolled to the left. The roll was uncommanded and caused partial loss of control. When the flight crew was trying to regain full control of the airplane, flap overspeed occurred. Following the flap overspeed the airplane was pitched down. The airplane’s speed continued to increase and the airplane started to descend rapidly. This resulted in the flight crew declaring an emergency.
The investigation revealed that the flight crew had regained full control of the airplane 2 minutes and 42 seconds after the uncommanded left roll. Three minutes and 22 seconds after the left roll and partial loss of control, the flight crew contacted ATC and advised that they had regained full control of the airplane and were ready to commence another approach to the airport.
The investigation revealed that the airplane had lost its right hydraulic system about the time when it reached top of descent towards Keflavik Airport. Then a latent failure of sub-component in the left wing spoiler #6 became activated when the flaps were fully extended prior to landing. The latent failure in spoiler #6 was traced to a design flaw in a sub-component of the spoiler, resulting in the sub-component cracking due to fatigue.
The Icelandic Transportation Safety Board issued five safety recommendations in the report. One for the spoiler‘s manufacturer (Moog), two for the airplane manufacturer (Boeing) and two for the Federal Aviation Administration (FAA).