This Week In Aviation History: The Crash Of Air India Express Flight 812

Human factors are a major factor in many aircraft accidents. Such was the case with Air India Express Flight 812 which crashed during landing on May 22, 2010. The accident investigation revealed poor crew communication while continuing an unstabilized approach as contributing factors. As a result, 158 occupants perished when the Boeing 737-800 overshot a runway in Mangalore, India. This event has been classified as the country’s third-deadliest aviation disaster.

The crash of an Air India Express B737 similar to this one was the third deadliest in the country’s history. Photo: Aero Icarus via Wikimedia Commons.

The right jet for the job

Air India Express operated a special variant of the Boeing 737-800 on its route connecting Dubai to Mangalore. The Boeing 737-8NG(SFP) was a limited production model with a short-field performance package perfectly suited for landing in airports with short runways. The aircraft’s manufacturer’s serial number 36333 with 2481 as its line number. The jet (registered as VT-AXV) was just under 3 years old and delivered to Air India Express in January 2008.

An Air India Express Boeing 737 on the ramp. Photo: Premkudva via Wikimedia Commons

Experienced 737 pilots

The flight crew consisted of pilots who were not new to flying a Boeing 737. The 55-year-old captain had amassed over 10,000 total flight hours including 2,440 hours on the Boeing 737. The 40-year-old first officer logged 3,620 flight hours with 3,319 on the Boeing 737. Both pilots had previous experience with this airport; the captain had landed at Mangalore 16 times, while the first officer had flown to the airport 66 times.

A challenging airport

The flight plan included departing Dubai International Airport and landing at Mangalore International Airport, which is situated on a hill. The terrain quickly drops from 200ft to 250ft immediately beyond the paved surface of the runway. Only two other airports in India have tabletop runways: Kozhikode and Lengpui.

The airport was initially used for limited domestic flights, (mainly to Mumbai and Bangalore), but later, the operation of international flights started in 2006 with Air India Express flying to Dubai, the departure airport from which Flight 812 originated. At the time of the accident, the operational training requirements in and out of Mangalore were not as stringent as they are today. This would later change because of the accident.

The chain of events

Air India Express 812 departed Dubai without issue and the flight had been uneventful before initiating the descent and approach to landing at Mangalore. In fact, the captain was asleep for 1 hour 40 minutes leaving the first officer to monitor the aircraft’s systems, navigation and communication with air traffic control during cruise. Later, the aircraft was cleared for the ILS DME arc approach into Mangalore.

The first officer continued to fly the approach despite the fact that Air India Express required the captain to land at Mangalore due to the complexity of the hilltop runway’s environment. Once the first officer had reported the 10-mile DME Arc, air traffic control requested an additional report when the aircraft was established on the localizer.

Speed brakes were deployed to slow the aircraft while increasing the angle of descent. Realizing they were too high at 8,500 ft., the captain lowered the landing gear with the speed brakes still deployed to further increase the descent rate. This was not sufficient, and now the aircraft was at nearly twice the altitude established for the correct interception of the ILS glideslope. The captain then selected a 40-degree flaps setting.

As the aircraft neared the 2.5-mile DME point, the first officer declared “It is too high” and “Runway straight down”. The captain responded with a verbal exclamation and followed by a manual steepening of the descent rate. Seemingly puzzled by the evolving situation, the first officer asked “Go around?”. The captain then mentioned being on the “wrong localizer…glidepath” which caused the first officer to again call for a go around, which he followed by the statement that the aircraft was “Unestablished”.

At this point, the accident report claims the aircraft was descending at nearly 4,000 feet per minute which activated several GPWS audiovisual alerts to emit their warning while air traffic control asked if the crew was established on the ILS. The cockpit voice recorder transcripts indicate the captain instructed the first officer to advise “Affirmative”. The tower controller then cleared the flight to land. The aircraft crossed the runway threshold at about 200 feet altitude with an indicated speed in excess of 160 kt, well beyond the published SOP of 50 feet with target speed of 144 knots for the landing weight.

The aircraft continued into the Runway End Safety Area (RESA) impacting the localizer antenna structure with its right wing before hitting the boundary fence and falling into a gorge.

The crash scene of Flight 812’s tragic runway overshoot. Photo: Neil Pinto via Wikimedia Commons.

Safety initiatives take flight

This was the first fatal accident for Air India Express but not the first overrun accident at Mangalore. On August 19th, 1981, Indian Airlines Flight 557, a Hawker Siddeley HS 748, overshot the 5,783-foot runway in rain. The turboprop overran the runway edge and was substantially damaged. The subsequent accident investigation cited an incorrect flap setting combined with a long landing on the downsloping runway. This was exacerbated by an excessive speed and tailwind.

A result of Flight 812’s accident investigation, India’s Directorate General of Civil Aviation (DGCA) compiled a list of airports it classified as “critical airfields”. This classification requires pilots to undergo required simulator training for those airports and conduct at least three flights under the supervision of an instructor pilot in the cockpit before being assigned to a revenue flight into one of these airfields.

In addition, airlines should include route competence to test pilots’ knowledge of flying above terrain, meteorological conditions and communication procedures with air navigators. Hopefully, this measure will prevent other overrun accidents at challenging Indian airports.