Danish Air Transport flight DTR54, an aircraft of type ATR 42 with registration mark OY-JRJ was on a scheduled flight from Bergen Airport Flesland (ENBR) to Florø Airport (ENFL). There were 22 passengers, 1 cabin crew member and 2 pilots on board.
During take-off the pilots experienced considerable control problems related to the elevator function. They declared an emergency situation and returned for landing. The landing was accomplished without further incident 7 minutes after take-off.
After landing it was found that the control problems were caused by the right elevator hanging below the horizontal stabiliser, attached only by the inboard of the three hinges that normally connect the elevator to the stabiliser.
A bolt was missing from both the centre and outer hinges.
Both of the bolts and one of the nuts that normally should connect the hinge assemblies together were found. One of the bolts was found on the runway, the other inside the elevator.
Investigation indicates that the bolt belonging to the outer hinge assembly fell out during the take-off in question, while the bolt in the centre hinge assembly had fallen out at an earlier point in time, without being discovered.
The report concludes that the self-locking nuts cannot have been tightened with the required torque when the elevator was fitted. This error was most probably introduced after the aircraft was repainted in 1999.
- The right elevator was probably installed on the stabiliser without the self-locking nuts on the centre and outboard hinge bolts being tightened to the correct torque following a major service and repaint of the aircraft in 1999. This has allowed the nuts over time to loosen from the bolts.
- The mandatory double inspection (error capturing method) following installation of the right elevator was not performed, or was performed unsatisfactorily.
- The elevator hinges will normally only be visible during a Detailed Visual Inspection of the Elevators Fittings (DVI), which is performed every 8th year. The DVI does not specify special attention to the bolts/nuts/bearings in the hinges.
- Detailed Visual Inspection of the Elevators Fittings (DVI) was performed in February 2003 without discovering the incorrect assembly.
- The bolt in the centre hinge assembly had, at an earlier point in time, probably several months before the accident, fallen out of the hinge and into a space in the elevator.
- The first officer registered that movement of the elevator required some more force than normal before take-off, but concluded that was probably because of wind.
- The bolt in the outboard hinge assembly fell out during take-off, so that the elevator was only attached to the stabiliser by the inboard hinge assembly during the flight in question.
- The outer part of the elevator was hanging below the stabiliser, which made it difficult to maintain control of the aircraft.
- The aircraft returned and landed 7 minutes after take-off without further incident.
- Power was not disconnected from the cockpit voice recorder, which had a capacity of 30 minutes, after landing, and recordings from the period in question were recorded over.