Investigation Summary
The investigation by the Accident Investigation Board Norway (AIBN) focused on why the BAe-146's six lift spoilers failed to extend despite the commander moving the lever to the correct position. The AIBN identified two primary mechanical possibilities: a failure in the spoiler lever mechanism itself or a simultaneous failure of two out of four thrust lever micro-switches. Because the spoilers did not deploy, the aircraft lacked the necessary aerodynamic drag and weight-on-wheels to brake effectively. The situation was exacerbated when the pilot, misidentifying the lack of deceleration as a wheel-brake failure, engaged the emergency brakes. This action bypassed the anti-skid system, causing the tires to lock and 'boil' the surface water into steam, a phenomenon known as reverted rubber hydroplaning. The aircraft's low-speed exit from the runway (15 to 20 knots) would likely have been survivable if not for the airport's geography; the steep slopes at the end of the runway caused severe structural damage, leading to a fuel leak and an intense fire fed by the number 2 engine that continued to run for more than five minutes after impact.
Final Conclusions
The AIBN concluded that the accident resulted from a combination of mechanical failure (spoilers), operational response (emergency braking leading to hydroplaning), and airport infrastructure (lack of runway grooving and steep safety areas). The investigation determined that had the spoilers functioned, or had the runway been grooved to prevent hydroplaning, the aircraft would likely have stopped within the available distance. Crucially, the AIBN also found that even without the spoilers, the aircraft could have stopped on the remaining runway if optimum braking had been maintained instead of engaging the emergency brakes which caused the wheels to lock. The final report (SL 2012/04) was published in April 2012.
Video Analysis
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Airframe & Maintenance
Crew Experience
Captain
34 years old at the time of the accident.
First Officer
38 years old at the time of the accident.
Systems & Failure Modes
Lift Spoilers
Aerodynamic surfaces on the wing that deploy upon landing to dump lift and increase drag, ensuring the aircraft's weight is firmly on the wheels for effective braking.
Emergency Braking System
A backup braking system that, when engaged, bypasses the anti-skid protection, allowing the wheels to lock completely if full pressure is applied.
Thrust Lever Micro-switches
Electrical switches that detect the position of the thrust levers to permit the deployment of spoilers only when the engines are at idle.
Interesting Facts
- 01The runway at Stord Airport was damp and lacked grooving, which is critical for preventing hydroplaning.
- 02The emergency braking system on the BAe-146-200A does not have anti-skid protection.
- 03Reverted rubber hydroplaning occurred, where steam generated by friction lifted the tires off the runway surface.
- 04The number 2 engine continued to run at high RPM for several minutes after the crash, fanning the flames and forcing all occupants to evacuate via the left-side exits as the right-side exits were blocked by fire and terrain.
- 05The aircraft was traveling at a relatively slow speed of 15 to 20 knots when it left the runway surface.
- 06The aircraft involved (MSN E2075) was manufactured in 1987.
Safety Actions & Advisories
Runway Grooving Requirements
The investigation highlighted the necessity of runway grooving at airports with short runways and steep surrounding terrain to prevent hydroplaning.
Spoiler Failure Procedures
The AIBN noted a lack of specific training or procedures for pilots in the event of a spoiler deployment failure during the landing roll.