What happened
On 1 August 2014, a Saab 91B "Safir" departed from runway 09 at Bremen Airport for a commercial flight under Visual Flight Rules. Shortly after the aircraft reached an altitude of approximately 300 ft AMSL, the pilot contacted the tower requesting an immediate landing. During the subsequent flight path, the aircraft entered a left-hand turn. During this maneuver, the aircraft's nose dropped, leading to a stall. The aircraft impacted the ground approximately 0.5 nautical miles northeast of the runway 27 threshold, striking a freight container and causing a significant fire. The crash resulted in two fatalities and the total destruction of the aircraft.
The investigation
The investigation examined the aircraft's mechanical condition, the pilot's experience, and the flight's final moments using radar data and witness photographs. Investigators found that the engine was functioning normally and showed no signs of power loss or mechanical failure. However, evidence suggested the oil filler cap had been left unsecured, likely following a pre-flight oil level check. This omission likely allowed oil vapors or spray to settle on the cockpit windscreen.
Analysis of the radar data and photographs revealed that the aircraft was in a clean configuration with the landing gear retracted. The investigation also noted that while the pilot was highly experienced in large transport aircraft, his recent training and proficiency checks specifically for the Saab 91B did not sufficiently cover the management of abnormal flight attitudes or stall recovery.