A Saurya Airlines jet crashed and skidded into a ravine during a botched takeoff in Kathmandu’s Tribhuvan International Airport in July as its pilot used the wrong takeoff weight information and inconsistent V-speeds, according to a preliminary probe report unveiled on Thursday.

The accident investigation commission’s report, posted on the Tourism Ministry’s website on Thursday, concluded that pilot error along with the negligence of operator and civil aviation regulator were responsible for the July 24 crash that killed 18 people onboard. The pilot was the lone survivor.

The probe report said the CRJ 200 aircraft, registered 9N-AME, suffered inconsistencies between its airspeed measurements and takeoff weight.

The flying pilot inserted incorrect speed measurements and take-off weight data into the flight computer, causing the aircraft to enter an aerodynamic stall (sudden decrease in lift), which the pilots failed to correct.

“The V-speeds mentioned in the flight plan and recorded in the flight data recorder (FDR) were inconsistent with those in the quick reference handbook,” according to the report.

The handbook available to pilots in the cockpit contains various procedures for dealing with abnormalities and emergencies.

“Also, the speed card of the operator for 18,500 kg take-off weight mentions incorrect V-speeds for takeoff,” said the report.

“That means the V-speeds, the specific airspeeds for various flight regimes, were set without calculating the aircraft's takeoff weight,” said a CRJ 200 engineer, who requested not to be named.

An aircraft’s weight determines required takeoff speeds, with heavier planes necessitating higher velocities for safe rotation.

There are three V speeds.

V1 is the maximum speed during the takeoff roll at which a pilot must decide whether to continue the takeoff or abort. If an engine fails before V1, the takeoff can still be safely aborted.

VR (Rotation Speed) is the speed at which the pilot initiates the aircraft's rotation to lift off the ground. It is typically higher than V1.

V2 refers to the minimum safe speed that must be maintained after takeoff in the event of an engine failure. It ensures that the aircraft can climb safely.

The report said that the inspection of the crash site, assessment of 9N-ANM, CRJ 200 aircraft and interviews with the ground personnel of Saurya Airlines revealed that the operator was not complying with the aircraft load weighing, loading and securing of load requirements stipulated in its operations manual.

For example, in ATR-type aircraft, the load weighing, loading and securing load requirements are followed, as the crew normally fills the seats in the front rows and only then allows passengers to sit in the tail section to maintain balance. Cargo is also placed accordingly. Also, the disembarkment rule is duly followed.

“In jet-type planes, these processes are not followed, and weight calculations are overlooked,” said the engineer.

The Saurya Airlines ferry flight was scheduled for heavy maintenance at Pokhara International Airport due to the unavailability of hangars in Kathmandu.

The report has blamed the civil aviation regulator for overlooking the ferry flight procedure.

The report added that the procedure followed in issuing the flight permission for the ‘ferry’ flight was inadequate, as the obtained records did not show completeness and compliance with the procedure manual for flight permission of the Civil Aviation Authority of Nepal.

The report said that the aircraft sank approximately 130 feet in four seconds. As a result of the blunt impact and disintegration of the plane, the most common cause of the death of persons onboard was blunt force trauma, followed by burn injury.

The aircraft underwent a right, left and right banks before the right wing struck the ground.

After rotating for takeoff, the aircraft attained a height of 50 ft above ground within five seconds and briefly climbed to just over 100 ft.

The report said that one fire vehicle arrived 1 minute 40 seconds after the impact and started spraying water after 15 seconds of arrival. Two other fire vehicles also arrived close to the accident site in the meantime, but they did not simultaneously participate in the firefighting efforts with the first vehicle.

Before the July 24 flight, the aircraft had been grounded for 34 days. “The preservation and return to service maintenance checks were carried out,” the report said.

During grounding, the aircraft was parked at the remote parking bay on the eastern side of the runway. The plane was returned to the domestic parking bay on July 23.

The report said that the maintenance documents are under comprehensive review.

The survey inspection for the renewal of the Certificate of Airworthiness was carried out on March 13, 2024. The main landing gear overhaul was due on April 17, 2024.

On April 20, 2024, the aircraft got an extension for both main landing gear, valid until June 19, 2024.

On April 26, 2024, a flight release certificate was issued based on the civil aviation regulator’s permit to fly the plane. On the same day, a test flight was conducted to renew the certificate of airworthiness.

After the expiry of the extension, the aircraft was grounded and sent for short-term storage, where it remained until July 19, 2024.

The return-to-service check was carried out on July 24, 2024, in the morning of the accident. The load and trim sheet was prepared before the flight. Load and trim sheet is one of the most important flight documents informing flight crew of the aircraft’s takeoff weight and details of loading, and aircraft takeoff centre of gravity.

As per the load and trim sheet, the listed take-off weight was 18,132 kg, including the baggage weight of 600 kg. The fuel on board weighed 2,000 kg.

The report said that the review and analysis of information on the load and trim sheet is ongoing.

According to preliminary analysis of the FDR data, no abnormalities were seen in engine parameters during the flight.

No adverse weather was reported.

Data extraction and recovery from both recorders were performed at the Transport Safety Investigation Bureau in Singapore.

The Aircraft Accident Investigation Commission has issued three interim safety recommendations.

First, all operators shall review their speedcards and regulated take-off weight charts immediately.

Second, operators are directed to comply with cargo and baggage handling requirements. Baggage and cargo weighing, distribution, and latching should be ensured as stipulated in the operation manual and ground handling manual.

Third, the Civil Aviation Authority of Nepal has been asked to review and update the requirements for permission for non-scheduled flights, including all non-revenue and ferry flights.