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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 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 (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 IMC)
  6. visual approach
  7. circling approach

Aircraft Accidents and Incidents Related to Unstabilised Approach Listed on SKYbrary

  • DH8A, vicinity Svolvær Norway, 2010 (On 2 December 2010, a DHC8-100 crew briefly lost control of their aircraft after encountering a microburst and came very close to both the sea surface and a stall when turning onto night visual final at Svolvær during an otherwise uneventful circling approach. After recovery from 83 feet agl, involving an unplanned change of control, an uneventful diversion to an alternate followed. Commencement of an investigation was delayed by failure to report the event at all initially, or fully. It was found that during loss of control, airspeed had dropped to 72 knots and rate of descent had exceeded 2,200 fpm.)
  • A320, vicinity Rapid City SD USA, 2016 (On 7 July 2016, an Airbus A320 crew cleared for a dusk visual approach to Rapid City mis-identified runway 13 at Ellsworth AFB as runway 14 at their intended destination and landed on it after recognising their error just before touchdown. The Investigation concluded that the crew had failed to use the available instrument approach guidance to ensure their final approach was made on the correct extended centreline and noted that it had only been possible to complete the wrong approach by flying an abnormally steep unstabilised final approach. Neither pilot was familiar with Rapid City Airport.)
  • C500, vicinity Santiago Spain, 2012 (On 2 August 2012, a Cessna 500 positioning back to base after completing an emergency medical team transfer operation earlier in the night crashed one mile short of the runway at Santiago in landing configuration after being cleared to make an ILS approach. The Investigation concluded that the approach was unstabilised, had been flown without following the ILS GS and that the crew had used DME distance from the VOR near the crash position rather than the ILS DME. Fog was present in and around the airport.)
  • B752, Puerto Plata Dominican Republic, 1998 (On 1 January 1998, a Boeing 757-200 being operated by Airtours International on a passenger charter flight from Bangor MA USA to Puerto Plata Dominican Republic struck the ground to the right of the intended landing runway shortly after the aircraft commander, flying manually as PF for a third approach, had initiated a late go around after failing to retain effective control of the aircraft. Despite sustaining substantial damage to the landing gear and airframe not appreciated by the flight crew, the aircraft was then successfully flown pressurised to the nominated diversion, Santo Domingo where an uneventful landing was accomplished. A fuel leak from the APU was observed once parked but the decision was taken to shut it down using the normal switch and not to expedite passenger disembarkation and no fire occurred. None of the occupants were injured during the landing attempt at Puerto Plata but the aircraft was found to have suffered extensive damage and had to be repaired before further flight by a team from the aircraft manufacturer.)
  • A320, vicinity Oslo Norway, 2008 (On 19 December 2008, an Aeroflot Airbus A320 descended significantly below its cleared and acknowledged altitude after the crew lost situational awareness at night whilst attempting to establish on the ILS at Oslo from an extreme intercept track after a late runway change and an unchallenged incorrect readback. The Investigation concluded that the response to the EGPWS warning which resulted had been “late and slow” but that the risk of CFIT was “present but not imminent”. The context for the event was considered to have been poor communications between ATC and the aircraft in respect of changes of landing runway.)
  • … further results


Stabilised Approach Awareness Toolkit for ATC

Further Reading

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Part of the Stabilised Approach Awareness Toolkit for ATC