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An operator encountered a lateral runway excursion. In this particular event the aircraft sustained minor landing gear damage but the contributing factors are in common with more serious incidents associated with adverse weather conditions (heavy precipitation, reduced visibility and a wet runway). This highlights the benefit of threat and error management training.
The chapters 1 to 4 are factual elements from the published report. Chapter 5 is the ATR additional comments. (Ref: article July 2022 – Decision making during approach) |
RUNWAY EXCURSION PREVENTION
| Event date : 02 June 2021 | Time : 22:27 UTC (17:27 LT) |
| Place : Eldorado international Airport – SKBO, Bogota, Colombia (elevation 8 360ft) | Aircraft : ATR 72-600 |
1. WEATHER INFORMATION
- METAR : SKBO 022100Z 31010KT 9999 VCSH SCT020CB SCT080 18/13 Q1023 TEMPO TS RMK CB/E/SE VCSH/NE/E
21:00Z wind 310°/10kt, visibility ≥ 10km, in the vicinity shower cumulonimbus, clouds scattered 8000 ft temperature 18°, dew point 13, QNH 1023, temporally thunderstorm, remark cumulonimbus east / southeast, in the vicinity shower northeast / East.
- METAR : SKBO 022200Z 02006KT 9999 3000SE -TSRA BKN020CB 17/14 Q1024 NOSIG RMK CB/SE
22:00Z wind 020°/6kt, visibility ≥ 10km, 3000m southeast, light thunderstorm rain, clouds broken 2000 ft cumulonimbus, temperature 17°, dew point 14, QNH 1024, no significant change, remark cumulonimbus southeast.
- 6 minutes before the event (22:21 UTC), a SPECI report was issued reporting: SKBO 022221Z 9999 2500E -TSRA SCT010 BKN020CB 15/14 Q1024 WS R31L NOSIG
22:21Z visibility ≥ 10km, 2500m east, light thunderstorm rain, clouds scattered 1000 ft, broken 2000 ft cumulonimbus, temperature 15°, dew point 14, QNH 1024, windshear RWY 31L, no significant change.
NOTE: the crew didn’t receive the SPECI during the flight.
Weather conditions – RADAR / SAT, 02 June 2021 – 22:20 UTC
Weather conditions on final approach runway 13L
The research obtained a photograph that provides an overview of the weather conditions present seven minutes before the event. The image shows the prominent reduction in visibility towards runway 13L due to precipitation.
2. SERIOUS INCIDENT DESCRIPTION
The ATR 72 aircraft was scheduled to fly from the Alcrán Airport (SKYP) of the City of Yopal, to the Eldorado International Airport (SKBO) of Bogotá.
The crew received from their dispatch, weather information, weight and balance sheet, NOTAMs and maintenance status.
- FOB (Fuel On Bord): 1,400 kg
- TOW (Take-Off Weight): 19,401 kg.
- CAPT (PF) – F/O (PM)
- Flight Time: ≈ 0h50
Approach (1000 ft AGL to 300 AGL)
| The aircraft reached 1,000 feet AGL established on the glide path, with the Autopilot engaged, a Vapp + 3kts, with a descent rate of -700 feet / min, and in a landing configuration (Flaps 30° / landing gear down). |
2 minutes before the event, the crew was authorized to land, with wind reported 170/15. The crew were prepared for a right crosswind.
The approach (ILS 13L) was stable down to AP disengagement at 270ft RA.
Approach 300 ft AGL to the ground.
In short final, the weather was heavy rainfall, hail and reduced visibility.
The aircraft bank was on the right due to the reported wind 170/15 (RWY 13).
DFDR data: The tailwind (previously measured at 10 knots), changed to headwind (up to ~14 knots, at 150 feet AGL) in 17 seconds. An estimated left crosswind increased from an average of 5 to 10 knots.
The IAS target (VAPP) was 105kt. Crossing ≈ 200 ft the IAS increased up to 123 kt (VAPP +18kt). At around 135 ft AGL, the estimated descent rate began to increase to 1050ft/min.
LANDING
The reported wind received by the crew was 170/15 (right crosswind). The crew applied the crosswind technique.
DFDR data: The estimated crosswind increased up to 22 knots from the left of the runway (calculated 050/22).
During the landing roll the crew didn’t identify the wind change from a right crosswind to a left crosswind. They momentarily lost control of the aircraft and there was a partial runway excursion on the right side. The crew regained control of the aircraft and managed to steer it back on the runway axis.
REPORT
The report highlights the information available to the flight crew from ATC and the two aircraft landing prior to the incident aircraft. This included information on windshear, heavy precipitation, a contaminated runway surface and reduced visibility.
The aircraft sustained minor landing gear damage from the partial excursion and caused damage to two runway edge lights.
GPS trace of the flight on landing
Runway Excursion Marks 13L
3 minutes after the event, the ATC canceled approaches on the runway 13L.
3. CONTRIBUTING FACTORS FROM THE REPORT
- Sudden increased IAS to Vapp+18 knots
- Increased vertical speed from up to -1166 ft/min at 300 ft AGL.
- Deteriorating weather conditions during approach and landing, related to heavy precipitation and reduced visibility.
- Wet runway condition at the airfield.
- Operation of the airfield under adverse weather conditions of heavy precipitation and wind shear.
- Deciding to continue the approach and landing maneuver under the adverse weather conditions (wind shear).
4. SAFETY RECOMMENDATION FROM THE REPORT
Safety recommendation to the operator:
- “….strengthen…the decision making and the evaluation of risks in the operation, during the execution of landing maneuvers in adverse, predictable and reported weather conditions.”
- Audit the company’s dispatch procedures, in relation to the processes of obtaining, applying, updating and sending updated weather information to crews, especially RADAR information, satellite images and TAF information.
Safety recommendation to Civil Aeronautics administration:
- “…….review the Circulars related to minimum use of aerodrome and applicable procedures for the closure of aerodromes…”
- “……make this Research Report known to the Regular Air Transport Operators that operate the ATR equipment, so that they apply the recommendations as appropriate…”
5. ATR RECOMMENDATIONS
Take benefit of threat & error management training to strengthen decision making in your operations. This applies to pre-departure, en-route and approach phases.
Threats are defined as “events or errors that occur beyond the influence of the flight crew, increase operational complexity, and which must be managed to maintain the margins of safety”.
The briefing is the opportunity to identify and highlight the key points which must be monitored during the approach.
“WINDSHEAR chapter.”
- In Approach:
- If a windshear is foreseen or reported, delay approach.
- If a windshear occurs, apply Windshear procedure during approach
(FCOM.NOP.ANOR.8 Windshear)
- BE prepared for a GO-AROUND
- Review the main task sharing (PM & PF) in a short briefing.
- Identify the Threat(s) on this specific approach. (Complex trajectory, congested airport, …)
- Identify the Threat(s) that could destabilize the approach (low visibility, wind, ATC runway change, …).
“Respect the stabilization criteria”
- Approaches must be stabilized and remain stable to touchdown
- 1000 ft AAL in IMC conditions
- 500 ft AAL in VMC conditions
- 300 ft AAL following circle-to-land
(FCTM – Stabilization policy)
- Respect the final approach speed – Vapp
(FCOM.LIM.3.4 Landing speed)
- Crosswind landing
- Disconnection of the autopilot and yaw damper should occur at the latest at 500 ft above airfield in order to have time to establish manual control.
(FCOM.PRO.NOP.ANOR.8 Operations in wind conditions)
Refer to previously published material available on the ATR Flight Safety website
6. REPORT
The final report in Spanish is available for download at Final investigation report
