Contribution of Unstabilised Approaches to Aircraft Accidents and Incidents

Contribution of Unstabilised Approaches to Aircraft Accidents and Incidents

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

On 4 December 2023, a Boeing 737-8200 crew misjudged positioning onto the ILS approach for arrival at London Stansted. Having decided to go around, they then continued to climb above the 3,000-foot missed approach altitude, which they had failed to set until alerted by the controller. The descent following a 1,000 feet level bust then continued back through the missed approach altitude at almost 9,000 fpm with an EGPWS ‘PULL UP’ warning just as recovery from 1,740 feet agl was initiated. After levelling at 3,000 feet, radar vectoring onto the ILS was provided with the approach then completed normally.

On 19 October 2022, an unstable approach to Sandy Lake by a de Havilland DHC8-300 was followed by a mishandled landing attempt by the first officer involving excessive pitch up and a tail strike. When the captain recognised a go-around was intended, he took over and completed the landing. The captain had recently been promoted after 3,000 hours as a first officer, and the first officer had just been released on his first two-pilot aircraft type after over 70 hours line training. The investigation noted that if an operator's safety management system (SMS) does not actively monitor flight data, unsafe practices may not be identified, increasing the risk that they will continue.

On 12 March 2022, an ATR76-600 captain made an unstabilised approach to Jabalpur, India, leading to a first bounce more than halfway along the runway and a final touchdown 400 metres from the runway end. The first officer took control but did not commence a go-around, and the aircraft overran the runway before stopping. The captain had just over four months command experience and had made six similar "high-severity long-flare" approaches in the previous five days. These had gone undetected because although such exceedances were supposedly being tracked by company flight data monitoring, this event was not being tracked.

On 11 February 2022 an Airbus A320 making a visual approach to Guadeloupe at night was advised by ATC of a descent below the minimum safe altitude. This advisory came as the crew continued the approach after visual reference was temporarily lost. A repeat of this warning by ATC prompted crew recognition that the aircraft was low and off the required approach track. A go-around was initiated from 460 feet agl. The decision to attempt a visual approach in unsuitable circumstances and a delay in recognising the need for a go-around were found to have been symptomatic of poor tactical decision-making.

On 31 January 2022, a Bombardier Challenger 604 pilot lost control during the final stages of a London Stansted night crosswind landing. A bounced nose-gear-first touchdown was followed by a brief runway excursion onto grass before a return to the runway and a climb away. A diversion to London Gatwick followed without further event but subsequent inspection revealed structural and other damage sufficient to result in the aircraft being declared an economic hull loss. The Stansted touchdown was found to have occurred after a premature flare at idle thrust continued towards the stall and a momentary stick pusher activation occurred.

 

Stabilised Approach Awareness Toolkit for ATC

Further Reading

CANSO

Part of the Stabilised Approach Awareness Toolkit for ATC

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