What happened
On the evening of 4 December 2014, a Saab 340B, registered VH-ZRJ, was operating a scheduled passenger service from Sydney to Narrandera, New South Wales. Shortly after departing from runway 34 Left, the crew failed to retract the landing gear. While the captain had issued a verbal command to retract the gear, the first officer did not recall hearing the instruction and did not perform the necessary action.
As the aircraft climbed, the crew focused on observing significant weather and thunderstorms in the area. During the climb checklist at approximately 3,800 feet, the crew realized the landing gear remained in the down position. In an instinctive reaction, the first officer moved the gear lever to the up position. However, the aircraft's airspeed had already reached 182 knots, which was 32 knots above the maximum landing gear retraction speed of 150 knots.
Despite the overspeed, the gear retracted normally and the aircraft continued to its destination. Subsequent inspections by engineers at both Narrandera and Wagga Wagga found no damage to the landing gear system.
The investigation
The investigation examined the crew's performance, the timing of the checklists, and the impact of fatigue. Investigators looked into why the verbal command was missed and why the error was not detected until the aircraft was traveling at high speed. The investigation also reviewed the first officer's sleep patterns and duty schedule leading up to the flight.
Findings
- The first officer was experiencing a level of fatigue that impaired performance; the officer had received only about two hours of interrupted sleep on the night preceding the flight.
- The first officer lacked the necessary training and objective tools to accurately self-assess their level of fatigue.
- The crew's attention was divided by heavy weather and the requirement to navigate a specific departure procedure, which contributed to the omission of the gear retraction.
- The crew likely operated under an expectation that the gear had already been retracted.
- The timing of the climb checklist allowed the error to go undetected until the aircraft had exceeded the safe speed limit for gear retraction.