Serious incident ATR 72-600 (72-212A) B-17010, Monday 10 May 2021
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Date:Monday 10 May 2021
Type:Silhouette image of generic AT76 model; specific model in this crash may look slightly different    
ATR 72-600 (72-212A)
Owner/operator:Uni Air
Registration: B-17010
MSN: 1150
Year of manufacture:2014
Total airframe hrs:13173 hours
Cycles:20087 flights
Engine model:Pratt & Whitney Canada PW127M
Fatalities:Fatalities: 0 / Occupants: 74
Other fatalities:0
Aircraft damage: Substantial, written off
Category:Serious incident
Location:Nangang Island-Matsu Nangan Airport (LZN) -   Taiwan
Phase: Landing
Nature:Passenger - Scheduled
Departure airport:Taipei-Songshan Airport (TSA/RCSS)
Destination airport:Nangang Island-Matsu Nangan Airport (LZN/RCFG)
Investigating agency: TTSB
Confidence Rating: Accident investigation report completed and information captured
UNI Air flight 9091, an ATR 72-600 (72-212A), registration B-17010, departed Taipei-Songshan Airport at 09:27 local time, on a flight to Nangang Island. The copilot was Pilot Flying.
The flight was cleared for an RNP approach to runway 21. At 10:05 the aircraft was at 958 feet and passed the minimum descent height. The flight reported runway in sight and continued the approach.
At a distance of 1.5 nm from the runway threshold, the aircraft dropped below the glide slope.
At 10:06:14, at about 0.15 nm from the runway, the pilot called "come and go around", and two seconds later, the autopilot was disconnected. Four seconds later the main landing gear and tail skid struck the top of a concrete perimeter wall
The flight crew continued the missed approach procedure and radioed that they suspected damage to the nose landing gear.
At 10:08, the flight crew requested to return to Songshan Airport.
Suspecting damage to the nose gear, the flight crew first flew a low pass over runway 10 at 10:45 hours. The tower controller at Songshan Airport reported observing damage to the right main gear wheels. The pilot decided to fly the traffic circuit with the gear down and landed on runway 10 at 11:07 hours.
The aircraft and the runway surface were damaged but there were no injuries.

Findings Related to Probable Cause:
When the occurrence aircraft performed a non-precision approach to runway 21 of Nangan Airport, the pre-threshold area was obscured by low clouds or marine fog. During the final approach, the pilot flying used the autopilot lateral navigation and vertical speed mode for the approach.
Focusing on flight operations in the cockpit, the pilot flying lost situational awareness of the aircraft position and did not realize that the aircraft altitude was very close to the runway threshold elevation. When the aircraft entered low clouds and was unable to maintain visual contact with the runway, the pilot flying did not follow the procedure of immediate execution of a go-around but continued using the autopilot for the approach, the pilot monitoring did not remind the pilot flying to execute or call for a go-around. When the pilot flying decided to perform a go-around, the aircraft had reached an altitude of 229 ft, 11 ft above the runway threshold elevation. Because the altitude was too low, before the aircraft could establish an effective positive rate of climb, the aircraft’s main wheels and tail skid collided with the top outer edge of the pre-threshold area of runway 21, causing substantial damage to the aircraft.

Accident investigation:
Investigating agency: TTSB
Report number: TTSB-FRP-21-09-001
Status: Investigation completed
Duration: 1 year and 4 months
Download report: Final report




Revision history:


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