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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

  • B744, vicinity Bishkek Kyrgyzstan, 2017 (On 16 January 2017, a Boeing 747-400F failed to successfully complete a night auto-ILS Cat 2 approach at Bishkek and the aircraft crashed and caught fire killing its occupants and 35 people on the ground and seriously injuring 36 others. The Investigation found that the flight crew had comprehensively failed to monitor the achieved approach flight path and, after capturing and flying down the false upper ILS GS lobe, had then failed to promptly initiate a go around at the applicable decision altitude. The fact that an automatic ILS approach could continue even on a false glideslope was noted.)
  • A332 / RJ1H, vicinity Zurich Switzerland, 2004 (On 31 October 2004, a Loss of Separation occurred between an A330-200, on a low go-around from Rwy 14 at Zurich Switzerland, and an Avro RJ100 which had been cleared for take-off on Rwy 10 and was on a convergent flight path.)
  • E145, Ljubljana Slovenia, 2010 (On 24 May 2010 the crew of a Regional Embraer 145 operating for Air France continued an unstable visual approach at Ljubljana despite breaching mandatory go-around SOPs and ignoring a continuous EGPWS ‘PULL UP’ Warning. The subsequent touchdown was bounced and involved ground contact estimated to have been at 1300fpm with a resultant vertical acceleration of 4g. Substantial damage was caused to the landing gear and adjacent fuselage. It was concluded that the type-experienced crew had mis-judged a visual approach and then continued an unstabilised approach to a touchdown with the aircraft not properly under control.)
  • 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.)
  • SW4, Sanikiluaq Nunavut Canada, 2012 (On 22 December 2012, the crew of a Swearingen SA227 attempting a landing, following an unstabilised non-precision approach at Sanikiluaq at night with questionable alternate availability in marginal weather conditions, ignored GPWS PULL UP Warnings, then failed in their attempt to transition into a low go around and the aircraft crashed into terrain beyond the runway. One occupant – an unrestrained infant – was killed and the aircraft was destroyed. The Investigation faulted crew performance, the operator and the regulator and reiterated that lap-held infants were vulnerable in crash impacts.)

... further results


Stabilised Approach Awareness Toolkit for ATC

Further Reading

CANSO

Part of the Stabilised Approach Awareness Toolkit for ATC