US Bangala Airlines flight UBG211 was operated on 12 March 12 2018 with a Bombardier DHC-8-402 (Q400) airplane registered S2-AGU from Hazrat Shahjalal International Airport, Dhaka, Bangladesh at 06:51 UTC to Tribhuvan International Airport, Kathmandu, Nepal.
The aircraft overflew part of Bangladesh and Indian airspace en-route to Nepal.
At 0641, Dhaka Ground Control contacted the aircraft requesting for its Bangladesh ADC number which was recently made mandatory a few weeks ago by Bangladesh authority for all international outbound flights.
The crew provided the ADC number as 2177 as provided in the Flight Plan.
The Ground Controller again asked the crew if they had the ADC for Bangladesh.
At 0642, PIC then contacted the Operations to confirm the Bangladesh ADC number.
As per the CVR records, changes in the PIC’s vocal pitch and language used indicated that he was agitated and experiencing high levels of stress at the time while communicating with Dhaka Ground Control and airlines operations.
The aircraft finally took off at 0651.
As the aircraft was in a climb phase, the PIC overheard a communication between Operations and another US Bangla aircraft regarding the fuel onboard but the PIC without verifying whether the message was meant for him or not, engaged in some unnecessary conversation with the Operations staff.
The Captain’s vocal pitch and language used indicated that he was very much emotionally disturbed and experiencing high level of stress.
US Bangala Airlines flight UBG211 established its first contact with Kathmandu Control at 0752:04. At 0807:49 the First Officer contacted Kathmandu Control and requested for descent.
Kathmandu Control gave descend clearance to FL160 with an estimated approach time of 0826 which was acknowledged by the First Officer.
At 0810 the flight was handed over to Kathmandu Approach.
At 0811, Kathmandu Approach instructed the aircraft to descend to 13500ft and hold over GURAS.
The crew inserted the HOLD in the Flight Management System.
At 0813:41 Kathmandu Approach further instructed the aircraft to reduce its speed and descend to 12500 ft.
At 0816 Kathmandu Approach instructed the aircraft to further descend to 11500 ft., and cleared for VOR approach RWY 02 maintaining minimum approach speed.
Both the crew forgot to cancel the hold on the FMS as they were engaged in some unnecessary conversation.
Upon reaching GURAS, the aircraft turned left to enter the holding pattern over GURAS, it was noticed by PIC and FO and immediately PIC made correction and simultaneously this was alerted to the crew by Approach Control also.
Once realizing the aircraft flying pattern and ATC clearance, the PIC immediately selected a heading of 027° which was just 5° of interception angle to intercept the desired radial of 202° inbound to KTM.
The spot wind recorded was westerly at 28kt. The aircraft continued approach on heading mode and crossed radial 202° at 7 DME of KTM VOR.
US Bangala Airlines flight UBG211 then continued on the same heading of 027° and deviated to the right of the final approach course.
Having deviated to the right of the final approach path, the aircraft reached about 2-3 NM North east of the KTM VOR and continued to fly further northeast.
At 0827, Kathmandu Tower (TWR) alerted the crew that the landing clearance was given for RWY02 but the aircraft was proceeding towards RWY 20.
At 0829, Tower Controller asked the crew of their intention to which the PIC replied that they would be landing on RWY02.
The aircraft then made an orbit to the right. The Controller instructed the aircraft to join downwind for RWY 02 and report when sighting another Buddha Air aircraft which was already on final for RWY 02.
The aircraft instead of joining downwind leg for RWY 02, continued on the orbit to the right on a westerly heading towards Northwest of RWY20.
The controller instructed the aircraft to remain clear of RWY 20 and continue to hold at present position as Buddha air aircraft was landing at RW02 (from opposite side) at that time.
After the landing of Buddha Air aircraft, Tower Controller, at 08:32 UTC gave choice to flight UBG211 to land either at RWY20 or RWY02 but the aircraft again made an orbit to the right, this time northwest of RWY 20.
While continuing with the turn through Southeastern direction, the PIC reported that he had the runway in sight and requested tower for clearance to land.
The Tower Controller cleared the aircraft to land but when the aircraft was still turning for the RWY it approached very close to the threshold for RWY20 on a westerly heading and not aligned with the runway.
At 08:33:27 UTC, spotting the aircraft maneuvering at very close proximity of the ground and not aligned with the RWY.
Alarmed by the situation, the Tower Controller hurriedly cancelled the landing clearance of the aircraft by saying, “Takeoff clearance cancelled”.
Within the next 15-20 seconds, the aircraft pulled up in westerly direction and with very high bank angle turned left and flew over the western area of the domestic apron, continued on a southeasterly heading through the ATC Tower and further continued at a very low height, flew over the domestic southern apron area and finally attempted to align with the RWY20 to land.
During this process, while US Bangala Airlines flight UBG211 was turning inwards and momentarily headed towards the control tower, the tower controllers ducked down their heads out of fear that the aircraft may hit the tower building.
Missing the control tower, when the aircraft further turned towards the taxi track aiming for the runway through a right reversal turn, the tower controller made a halfhearted transmission by saying, “UBG211, I say again…”.
At around 0834 UTC the aircraft touched down 1700 meters down the threshold with a bank angle of about 15 degrees and an angle of about 25 degrees with the RWY axis (approximately heading Southeast) and on the left of the center line of RWY 20, then veered southeast out of the runway through the inner perimeter fence along the rough down slope and finally stopped at coordinates N2741’41”, E08521’32” about 442 meters southeast from the first touchdown point on the runway.
All four crew members (2 cockpit crew and 2 cabin crew) and 45 out of the 67 passengers onboard the aircraft were killed in the accident.
Two more passengers succumbed to injury later in hospital during course of treatment.
The aircraft caught fire after 6 seconds of touchdown which engulfed major portions of the aircraft.
The weather at the moment of crash was the following:
- Wind: Westerly 07 to 08 kts.
- Visibility: 06 to 07 km.
- Cloud: Scattered (3-4 Oktas) low clouds and few (1-2 Oktas) cumulonimbus cloud Cumulonimbus was observed towards Southeast, South and Southwest direction of Kathmandu valley
- Temperature: 21C.
- Meteorological Conclusion:
The sky was generally cloudy with cumulonimbus cloud seen towards southeast, south and southwest direction of the valley.
The Probable Causes of US Bangala Airlines flight UBG211 crash :
The Accident Investigation Commission determines that the probable cause of the accident is due to disorientation and a complete loss of situational awareness in the part of crewmember.
Contributing to this the aircraft was offset to the proper approach path that led to maneuvers in a very dangerous and unsafe attitude to align with the runway. Landing was completed in a sheer desperation after sighting the runway, at very close proximity and very low altitude.
There was no attempt made to carry out a go around, when a go around seemed possible until the last instant before touchdown on the runway.
- Improper timing of the pre-flight briefing and the commencement of the flight departure in which the operational pre-flight briefing was given in early morning but the flight departure time was around noon and there were four domestic short flights scheduled in between.
- The PIC, who was the pilot flying, seemed to be under stress due to behavior of a particular female colleague in the company and lack of sleep the preceding night.
- A very steep gradient between the crew.
- Flight crew not having practiced visual approach for runway 20 in the simulator.
- poor CRM between the crew.
- Failure to ARM the VOR to intercept the desired radial (Aircraft never intercepted the radial, rather it crossed over from left to right of the desired approach path of the runway while remaining on HDG Mode with AP ON);
- Failure to adhere to the standard operating procedure. Failure to perform proper briefing.
- Not noticing the unsafe gear warning horn by the crew until approaching the MDA.
- PIC did not make corrective action to EGPWS warnings on time.
- Failure to carry out a standard missed approach procedure in spite of the runway not being visual at the MDA.
- Failure to meet the stabilization criteria of the aircraft on approach.
- Increased workload on the PIC as he was manually flying the airplane and communicating with the ATC;
- Loss of situational awareness due to miss-alignment with the runway during initial approach, and eventually not being able to sight the runway;
- High bank angle, rapid descent, excessive threshold speed, inadequate inner rudder input contributed for hard contact of the right main landing gear to the runway.
- The speed, altitude and the radial was never monitored during approach.
- Lack of assertiveness on the part of Air Traffic controller in monitoring the flight path of the aircraft and not issuing a clear instruction to carry out a standard missed approach procedure.
- Lack of clear understanding and acknowledgment on the part of both ATC and the crew to clearly understand each other’s communication regarding the landing runway.
- Lack on the part of the ATC to alert the crew of their actual position.
- Even though the copilot was operating to Kathmandu (CAT C) for the first time, the provision of a safety pilot which was not given a importance could have been of a great help in the situation.
- Lack of simulator training dedicated to the visual approach for runway 20 to the PIC.