What happened
On the early morning of December 11, 2001, a Piper Chieftain, registration OH-PNX, operated by Turku Air Oy, was involved in a serious ground incident at Oulu Airport. The aircraft was scheduled for a night cargo flight from Oulu to Rovaniemi.
During the taxi phase, the pilot experienced difficulty maintaining situational awareness due to heavy fog and nighttime conditions. While taxiing, the pilot mistakenly adjusted the directional gyro by 18 and 180 degrees in the wrong direction. This error led the pilot to believe the aircraft was on the correct path, when in fact the aircraft was heading toward the runway in the opposite direction of the assigned clearance. Upon reaching the runway, the pilot initiated a takeoff roll in the wrong direction. The air traffic controller observed the deviation and immediately ordered the aircraft to stop. The pilot complied, bringing the aircraft to a halt well before the end of the runway.
The investigation
The investigation examined the pilot's physiological state, the aircraft's navigational systems, and the operator's procedures. Investigators found that the pilot had been awake for approximately 20 hours prior to the incident and had not eaten for roughly nine hours. The investigation also reviewed the airport's lighting and signage, as well as the company's operational manuals regarding low-visibility operations.
Findings
- The primary cause of the incident was that the pilot failed to verify the taxi route against a map or external landmarks, incorrectly set the directional gyro, and did not follow runway holding position signage.
- The pilot failed to cross-check the directional gyro reading against the magnetic compass or the secondary gyro.
- Contributing factors included the pilot's lack of familiarity with Oulu Airport, the presence of thick fog, and physiological factors, specifically extreme fatigue and low blood sugar due to prolonged wakefulness and lack of nutrition.
- Deficiencies were identified in Turku Air Oy's operating procedures, particularly regarding low-visibility operations and the calculation of required runway lengths and obstacle clearance.
Safety action
Following the investigation, the following recommendations were made:
- Pilots should manage their circadian rhythms and account for the impact of sleep deprivation and nutrition on alertness.
- Turku Air Oy should establish Standard Operating Procedures (SOPs) for low-visibility operations.
- The operator should implement a policy to always utilize the full runway length during low-visibility takeoffs to minimize the risk of disorientation.
- The company's takeoff techniques should be updated to align with the original Pilot's Operating Handbook (POH) to ensure accurate obstacle clearance calculations.