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SAFETY RECOMMENDATIONS
[/FONT][/FONT] The Accident Investigation Board Norway (AIBN) makes the following safety
recommendations:
[FONT=TimesNewRoman,Bold] Safety recommendation SL 2015/01T
[/FONT] During its approach to Kittilä on 26 December 2012, LN-DYM came close to stalling as
a result of a blocked elevator. AIBN's investigation has documented that, even after the
introduction of new de-icing procedures from Boeing, considerable volumes of fluid and
pertaining humidity are penetrating the Tail Cone Compartment during de-icing of the
Boeing 737 aircraft type. The investigation shows fluid penetration toward the four Input
cranks on the aircraft's two Power Control Units. If this fluid freezes in the narrow gap
between the Input cranks, this may result in blockage of the Power Control Units. This
prevents operation of the elevator on Boeing 737 with potentially catastrophic outcome.
AIBN recommends that the aircraft manufacturer Boeing conduct a new safety
assessment of the Boeing 737 aircraft type as regards blockage of the aircraft type's
elevator system, and establish measures in order to satisfy the requirements in FAR Part
25 § 25.671 and EASA CS-25 §25.671. (Similar safety recommendations are also issued
to the FAA and EASA).