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:
- Runway excursions
- Landing short
- Controlled flight into terrain
- Hard landings
- Tail Strike
Contributory factors
Weather conditions or approach types which can increase the chances of an unstabilised approach are:
- wake turbulence
- strong winds
- low visibility
- heavy precipitation
- an approach with no visual references (e.g. night or Instrument Meteorological Conditions (IMC))
- visual approach
- circling approach
Aircraft Accidents and Incidents Related to Unstabilised Approach Listed on SKYbrary
On 12 March 2022, an ATR76-600 Captain made an unstabilised approach to Jabalpur before a first bounce more than half way 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 but 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 after continuing the approach after visual reference was temporarily lost. A repeat of this warning by ATC prompted crew recognition that the aircraft was not on the required approach track or profile and 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.
On 27 January 2020, an MD83 made an unstabilised tailwind non-precision approach to Mahshahr with a consistently excessive rate of descent and corresponding EGPWS Warnings followed by a very late nose-gear-first touchdown. It then overran the runway end, continued through the airport perimeter fence and crossed over a ditch before coming to a stop partly blocking a busy main road. The aircraft sustained substantial damage and was subsequently declared a hull loss but all occupants completed an emergency evacuation uninjured. The accident was attributed to the actions of the Captain which included not following multiple standard operating procedures.
On 28 April 2018, a Dassault Falcon F900B came into close proximity with a Beech B36T Bonanza at the uncontrolled VFR-only aerodrome at Bremgarten during its tailwind approach to runway 23 made without contacting the designated Flight Information frequency as the other aircraft was on approach to runway-in-use 05 and in contact with Flight Information. The Beech pilot took avoiding action by turning north and climbing in order to avoid a collision. The Falcon 900 crew had not prepared for the approach which was then unstabilised with late gear extension and multiple EGPWS ‘SINK RATE’ warnings annunciated.
Further Reading
- Stabilised Approach
- Global Action Plan for the Prevention of Runway Excursions (GAPPRE), 2021
- DGAC (France) Publications on Non-Stabilised Approaches
- CFIT Precursors and Defences
- Continuous Descent Final Approach (CDFA)
- Non-stabilised Approach After ATC-Requested Runway Change (OGHFA SE)
- Runway Overrun After Unstabilised Approach (OGHFA SE)
CANSO