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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

  • B735, vicinity Kazan Russia, 2013 (On 17 November 2013, the crew of a Boeing 737-500 failed to establish on the ILS at Kazan after not following the promulgated intermediate approach track due to late awareness of LNAV map shift. A go around was eventually initiated from the unstabilised approach but the crew appeared not to recognise that the autopilot used to fly the approach would automatically disconnect. Non-control followed by inappropriate control led to a high speed descent into terrain less than a minute after go around commencement. The Investigation found that the pilots had not received appropriate training for all-engine go arounds or upset recovery.)
  • B733, vicinity Kosrae Micronesia, 2015 (On 12 June 2015, a Boeing 737-300 crew forgot to set QNH before commencing a night non-precision approach to Kosrae which was then flown using an over-reading altimeter. EGPWS Alerts occurred due to this mis-setting but were initially assessed as false. The third of these occurred when the eventual go-around was initially misflown and descent to within 200 feet of the sea occurred before climbing. The Investigation noted failure to action the approach checklist, the absence of ATC support and the step-down profile promulgated for the NDB/DME procedure flown as well as the potential effect of fatigue on the Captain.)
  • B752, Girona Spain, 1999 (On 14th September 1999, a Britannia Airways Boeing 757 crash landed and departed the runway after a continued unstabilised approach in bad weather to Girona airport, Spain.)
  • A332, Jakarta Indonesia, 2013 (On 13 December 2013, an Airbus A330 encountered very heavy rain below 100 feet agl just after the autopilot had been disconnected for landing off an ILS approach at Jakarta. The aircraft Commander, as pilot flying, lost visual reference but the monitoring First Officer did not. A go around was neither called nor flown and after drifting in the flare, the aircraft touched down with the right main landing gear on the grass and continued like this for 500 metres before regaining the runway. The Investigation noted that prevailing SOPs clearly required that a go around should have been flown.)
  • DH8C, vicinity Sydney Australia, 2008 (On 26 December 2008, a DHC8-300 being operated by Eastern Australia Airlines from Moree to Sydney made an auto ILS approach in which became de-stabilised and was continued as such until a stick shaker activation occurred.)

... further results


Stabilised Approach Awareness Toolkit for ATC

Further Reading

CANSO

Part of the Stabilised Approach Awareness Toolkit for ATC