What happened
On May 10, 2021, an EVA Air ATR72-212A, registration B-17010, was performing a scheduled passenger flight from Taipei Songshan Airport to Matsu Nangan Airport. The aircraft was carrying 70 passengers and 4 crew members. During the approach to runway 21, the aircraft encountered low clouds or sea fog covering the runway threshold area.
While utilizing autopilot in vertical rate mode, the flying pilot lost situational awareness regarding the aircraft's altitude relative to the terrain. As the aircraft entered the low visibility area, the crew failed to execute a timely missed approach. At an altitude of approximately 229 feet—only about 11 feet above the threshold elevation—the pilot initiated a go-around. However, the aircraft was too low to establish an effective climb rate, resulting in the main landing gear and the tail skid striking the top of the outer edge wall of the runway 21 threshold. The aircraft subsequently returned to Songshan Airport, where it landed on runway 10. There were no fatalities or injuries, though the aircraft and the runway surface sustained damage.
The investigation
The Taiwan Transportation Safety Board (TTSB) examined the flight data, cockpit voice recorder, and airport infrastructure. The investigation established that the crew was operating under non-precision approach procedures. The investigation also reviewed the weather reports, which noted haze and scattered clouds at 300 feet, but did not capture the specific sea fog lifted by terrain near the threshold. Furthermore, the investigation identified discrepancies between the published runway distances at Nangan Airport and the actual physical configuration of the runway threshold markings.
Findings
- The primary cause was the failure of the flying pilot to execute an immediate missed approach upon losing visual contact with the runway while flying through low clouds/sea fog.
- The flying pilot's attention was focused on cockpit operations, leading to a loss of situational awareness regarding the aircraft's height.
- The pilot failed to disconnect the autopilot and transition to manual control above the 160-foot threshold elevation as required by operating limitations.
- The monitoring pilot failed to intervene or call for a missed approach despite the aircraft being significantly below the correct glide path and the flying pilot deviating from standard operating procedures (SOPs).
- The airline's safety monitoring mechanisms were unable to specifically detect these types of SOP deviations during the final approach phase.
Safety action
- The TTSB recommended that EVA Air strengthen its safety monitoring to identify and prevent SOP deviations and ensure monitoring pilots fulfill their role in crew cooperation and error correction.
- Recommendations were made to enhance Controlled Flight Into Terrain (CFIT) risk management, including improved hazard identification and safety performance indicators.
- The Civil Aeronautics Administration (CAA) was advised to oversee these improvements and to evaluate the installation of auxiliary equipment or observation guidelines at Nangan Airport to better detect sea fog near the runway threshold.
- A review of runway end safety areas and published distances at Nangan Airport was recommended to ensure compliance with airport design and operation standards.