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Contribution of Unstabilised Approaches to Aircraft Accidents and Incidents

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Article Information
Category: Toolkit for ATC - Stabilised Approach Stabilised Approach Awareness Toolkit for ATC
Content source: EUROCONTROL EUROCONTROL
Content control: EUROCONTROL EUROCONTROL

Description

The Flight Safety Foundation (FSF) established that unstabilised approaches were a causal factor in 66 % of 76 approach and landing accidents and incidents worldwide between 1984 and 1997.

It was found that many low and slow (low energy) approaches have resulted in controlled flight into terrain (Controlled Flight Into Terrain (CFIT)) because of inadequate vertical position awareness. Low energy approaches may also result in "loss-of-control" or "land-short" events.

High energy approaches have resulted in runway excursions and also have contributed to inadequate situational awareness in some of CFIT accidents.

It was found that a crew’s inability to control the aircraft to the desired flight parameters (airspeed, altitude, rate of descent) was a major factor in 45 % of 76 approach-and-landing accidents and serious incidents.

Flight-handling difficulties have occurred in situations which included rushing approaches, attempts to comply with demanding ATC clearances, adverse weather conditions and improper use of automation.

Consequences

Unstabilised approaches can be followed by:

  1. Runway excursions
  2. Landing short
  3. Controlled flight into terrain
  4. Hard landings
  5. Tail Strike

Contributory factors

Weather conditions or approach types which can increase the chances of an unstabilised approach are:

  1. wake turbulence
  2. strong winds
  3. low visibility
  4. heavy precipitation
  5. an approach with no visual references (e.g. night or Instrument Meteorological Conditions (IMC))
  6. visual approach
  7. circling approach

Aircraft Accidents and Incidents Related to Unstabilised Approach Listed on SKYbrary

  • D228, vicinity Bodø Norway, 2003 (On 4 December 2003, the crew of a Dornier 228 approaching Bodø lost control of their aircraft after a lightning strike which temporarily blinded both pilots and damaged the aircraft such that the elevator was uncontrollable. After regaining partial pitch control using pitch trim, a second attempt at a landing resulted in a semi-controlled crash which seriously injured both pilots and damaged the aircraft beyond repair. The Investigation concluded that the energy in the lightning had probably exceeded certification resilience requirements and that up to 30% of the bonding wiring in the tail may have been defective before lightning struck.)
  • A319, vicinity Wuxi China, 2010 (On 14 September 2010, the crew of a Sichuan Airlines Airbus A319 continued an ILS approach into Wuxi despite awareness of adverse convective weather conditions at the airport. Their inattention to automation management then led to a low energy warning and the inappropriate response to this led to the activation of flight envelope protection quickly followed by a stall warning. Inappropriate response to this was followed by loss of control and a full stall and high rate of descent from which recovery was finally achieved less than 900 feet agl.)
  • B733, Yogyakarta Indonesia, 2011 (On 20 December 2011, the experienced Captain of a Sriwijaya Air Boeing 737-300 flew an unstabilised non-precision approach to a touchdown at Yogyakarta at excessive speed whilst accompanied by a very inexperienced First Officer. The aircraft overran the end of the 2200 metre-long wet runway by 75 metres . During the approach, the Captain 'noticed' several GPWS PULL UP Warnings but no action was taken. The Investigation attributed the accident entirely to the actions of the flight crew and found that there had been no alert calls from the First Officer in respect of the way the approach was flown.)
  • AT72, Mumbai India, 2009 (On 10 November 2010, a Kingfisher Airlines ATR 72-200 made an excessively steep and unstabilised tailwind approach in light rain to runway 27 at Mumbai in visual daylight conditions. After touching down late, the aircraft was steered off the side of the runway when it became obvious that an overrun would otherwise occur. The Investigation found that ATC had failed to advise of water patches on the runway and aquaplaning had occurred. It also found that without aquaplaning, the available distance from the actual touchdown point would have been sufficient to stop the aircraft in.)
  • JS31, Fort St. John BC Canada, 2007 (On 9 January 2007, a Peace Air British Aerospace Jetstream 31 on a scheduled service flight from Grand Prairie, Alberta made an instrument approach to Runway 29 at Fort St. John, British Columbia and touched down 320 feet short of the runway striking approach and runway threshold lights.)

... further results


Stabilised Approach Awareness Toolkit for ATC

Further Reading

CANSO

Part of the Stabilised Approach Awareness Toolkit for ATC