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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

  • RJ1H, vicinity Zurich Switzerland, 2011 (On 20 July 2011, the flight crew of a Swiss European Avro RJ-100 on a positioning flight from Nuremburg to Zurich responded inappropriately to an unexpected ‘bank angle’ alert in IMC. Near loss of control followed during which a PAN was eventually declared. The situation was resolved by a belated actioning of the QRH checklist applicable to the failure symptoms experienced. The subsequent investigation attributed the event to inappropriate crew response to a failure of a single IRU and poor manual flying skill whilst the situation was resolved.)
  • B733, vicinity Bournemouth UK, 2007 (On 23 September 2007, the pilots of a Thomsonfly Boeing 737-300 almost lost control of their aircraft after initiating a go around from an unstable low airspeed and low thrust condition reached progressively but unnoticed during an approach to Bournemouth at night. Mismanagement of the aircraft during the go around was attributed to a lack of adequate understanding of the aircraft pitch control system and led to extreme pitch and an aerodynamic stall but the crew subsequently recovered control of the aircraft and an uneventful second approach and normal landing followed.)
  • 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.)
  • 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.)
  • A321, vicinity Deauville France, 2013 (On 26 September 2013, an Airbus A321 approaching Deauville in day VMC was advised that only a GNSS instrument approach - for which the crew were not approved - was available for the active runway. During the subsequent visual approach, the crew lost sight of the runway whilst over the sea and descended to almost the same height as the land ahead, eventually triggering an EGPWS ‘PULL UP’ Warning. The approach was subsequently abandoned after an EGPWS ‘SINK RATE’ Alert on short finals and non-standard positioning to the opposite runway direction, followed by a landing in the originally expected direction.)

... further results


Stabilised Approach Awareness Toolkit for ATC

Further Reading

CANSO

Part of the Stabilised Approach Awareness Toolkit for ATC