If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user

 Actions

Contribution of Unstabilised Approaches to Aircraft Accidents and Incidents

From SKYbrary Wiki

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.)
  • CRJ2, Providence RI USA, 2007 (On 16 December 2007, a Bombardier CRJ-200 being operated by Air Wisconsin on a scheduled passenger flight from Philadelphia, PA to Providence RI made an ILS approach to Runway 05 at destination in IMC which became unstable but was continued to an extremely hard night touchdown which broke the left hand main landing gear and was followed by exit of the aircraft from the left hand side of the runway and a slide through a snow-covered grassy area before it came to a stop without impacting any obstructions. There were no injuries to the occupants, who left the aircraft using the integral air stairs at the main door but the aircraft suffered “substantial” damage.)
  • B738, Sint Maarten Eastern Caribbean, 2017 (On 7 March 2017, a Boeing 737-800 crew making a daylight non-precision approach at Sint Maarten continued it without having established the required visual reference to continue beyond the missed approach point and then only realised that they had visually ‘identified’ a building as the runway when visibility ahead suddenly improved. At this point the approach ground track was corrected but the premature descent which had inadvertently been allowed to occur was not noticed and only after the second of two EGPWS Alerts was a go-around initiated at 40 feet above the sea.)
  • B738/B738, vicinity Oslo Norway, 2012 (On 31 October 2012, a Boeing 737-800 on go around after delaying the breaking off of a fast and high unstable ILS approach at Oslo lost separation in IMC against another aircraft of the same type and Operator which had just taken off from the same runway as the landing was intended to be made on. The situation was aggravated by both aircraft responding to a de-confliction turn given to the aircraft on go around. Minimum separation was 0.2nm horizontally when 500 feet apart vertically, both climbing. Standard missed approach and departure tracks were the same.)
  • E55P, Blackbushe UK, 2015 (On 31 July 2015 a Saudi-operated Embraer Phenom on a private flight continued an unstabilised day visual approach to Blackbushe in benign weather conditions. The aircraft touched down with excess speed with almost 70% of the available landing distance behind the aircraft. It overran and was destroyed by impact damage and fire and all occupants died. The Investigation concluded that the combination of factors which created a very high workload for the pilot "may have saturated his mental capacity, impeding his ability to handle new information and adapt his mental model" leading to his continuation of a highly unstable approach.)

... further results


Stabilised Approach Awareness Toolkit for ATC

Further Reading

CANSO

Part of the Stabilised Approach Awareness Toolkit for ATC