Last-minute conversation between pilot, control tower was ‘abnormal’: US-Bangla plane crash investigators

The commission formed by the Nepal government to investigate the US-Bangla Airlines plane crash has released a preliminary report.

According to the five-page report made available on Monday, the pilot of the ill-fated Flight UBG 211, callsign Bangla Star 211, from Dhaka and the air traffic control tower of Tribhuvan International Airport in Kathmandu had an ‘abnormal’ conversation before the crash on Mar 12.      

The plane crashed at 2:19:10pm local time. The report says the transmission between the pilot and the control tower was normal until 2:17:58pm.  

A few transmissions were made by both ATC and the pilot until 2:18:45pm, “but no corresponding replies or acknowledgements were made from either side,” the report says.

The Bombardier Dash 8 Q400 plane crashed after 25 more seconds, killing 49 of 71 people on board. Two of the 22 survivors succumbed to their injuries later.

The 52 deceased include 27 Bangladeshis. The survivors suffered severe burns and other injuries.     

The last-minute conversation between the pilot and the control tower has been in the centre of discussions on reasons behind the crash.

An audio clip of the conversation was published on YouTube, citing which the US-Bangla authorities said ‘wrong signals’ from the control tower might have led to the crash.

News portal Aviation Nepal wrote, “As per the report, the air traffic controllers at the airport have not been able to make the right decision at the time.

“In the initial report, the accident took place after the pilot followed the missed approach procedure losing 52 souls at the accident,” it added.

Photo: Reuters

The Commission says its preliminary report is based on initial information gathered from the crash site and documents obtained so far from all involved authorities and organisations.

The reviewing of the available documents and testing, decoding, research and analysis of all pertinent equipment retrieved from the aircraft are ongoing and shall be included in the final report, it says.  

It will also provide causes or contributing factors of the crash in the final report.

Capt Salahuddin M Rahmatullah, Senior Consultant and Chief Flight Operations Inspector, Civil Aviation Authority of Bangladesh, is representing the country in the Commission.

Capt Rahmatullah, who is also heading the CAAB investigation team, spoke to reporters on Thursday about different sides of the initial report.

He said there was a ‘gap’ in the conversation between the pilot and the control tower before the crash.

“The communications must be two-way when an aircraft lands. Some communications of the final moments before the crash could not be retrieved,” he said.

According to him, there was no problem in the aircraft, weather and the navigation system of the airport.

“It can’t be said only on assumptions how the accident occurred. We can’t tell you the cause of the accident now,” he added.

The CAAB official also said they published the initial report as International Civil Aviation Organisation rules stipulate publication of a report within a month from any accident. The final report has to be filed within a year, but the time can be extended, according to ICAO.

Capt Rahmatullah said they will also include some recommendations on avoiding such accidents in the future.

Source: Hamburg-based Jacdec, a news website on air travel safety.

How the plane crashed

The southern end of the lone runway of the Tribhuvan International Airport is identified as Runway 02 while the northern end is Runway 20.

Many aviation experts said the last four minutes’ conversation indicated there might have been confusion in the cockpit over the runway.

The Commission has not drawn any conclusion on the issue in the initial report.

It said the aircraft touched down at about 1700 metres down the threshold and on the left portion of centreline of Runway 20.

The aircraft then travelled on ground towards southeast, went out of the runway, ran through the inner perimeter fence of the airport area, moved down along rough downslope and finally stopped at about 442 metres southeast side of the runway from its initial touch down point.

At this point, the aircraft caught fire and was completely destroyed, the report says.

Rescue workers work at the wreckage of a US-Bangla airplane after it crashed at the Tribhuvan International Airport in Kathmandu, Nepal March 12, 2018. REUTERS

The findings

The report says the Certificate of Airworthiness of the aircraft, manufactured 16 years ago, was valid until July 7 this year and Certificate of Release to Service (Line Maintenance) until June 29.

During the crash, the westerly wind was dominating with speed of 7 to 8 knots.

The prevailing visibility was 6 to 7 kilometres.

The sky was covered with scattered low cloud and few cumulonimbus cloud, the report says and adds the cumulonimbus was observed over the southern side of the Kathmandu valley at southeast, south and southwest direction with thunder and lighting.

Referring to eyewitnesses and the statements submitted by the authorities, the rescue and firefighting team immediately rushed to the crash site, fought the fire and rescued survivors and victims with utmost efficiency.