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From SKYbrary Wiki
Plan Continuation Bias
(Plan) Continuation Bias is the unconscious cognitive bias to continue with the original plan in spite of changing conditions.
Unconscious bias in thinking leads to a pilot or controller following the originally-intended course of action. This bias appears to be stronger as the culmination of a task nears, for example during the flying of an approach to land or the maintenance of the planned separation between aircraft sequenced for approach to a particular runway.
Continuation Bias may have the effect of obscuring subtle cues which indicate that original conditions and assumptions have changed. It may also act in combination with other cognitive biases.
Accidents and Incidents
SKYbrary includes the following reports relating to events where continuation bias was considered to be a factor:
- Vehicle / UNKN, Singapore Changi, 2013 (On 4 April 2013, during a brief daytime runway closure for inspection purposes, a vehicle entered the runway without ATC awareness and was still there when the runway was re-opened and the first landing clearance was issued. TWR control subsequently observed the vehicle on the runway visually but, when they were unable to make contact with it, instructed the aircraft on final approach to go around when it was just under 1nm from touchdown. It was discovered that the vehicle involved had been in broken contact with another nearby aerodrome because the wrong radio frequency had been selected.)
- B737, New York La Guardia USA, 2016 (On 27 October 2016, a Boeing 737-700 crew made a late touchdown on the runway at La Guardia and did not then stop before reaching the end of the runway and entered - and exited the side of - the EMAS before stopping. The Investigation concluded that the overrun was the consequence of a failure to go around when this was clearly necessary after a mishandled touchdown and that the Captain's lack of command authority and a lack of appropriate crew training provided by the Operator to support flight crew decision making had contributed to the failure to go around.)
- TBM8, Birmingham UK, 2011 (On 12 January 2011, a privately operated Socata TBM850 light aircraft on a flight from Antwerp to Birmingham lost radio contact with ATC whilst in IMC on a non precision approach to runway 15 prior to the issue of a landing clearance and prior to checking in on the ATC TWR frequency. It continued the approach to obtain the required visual reference before landing over the top of a DHC8-400 aircraft which had lined up ready for take off in accordance with ATC instructions. No damage or personal injury resulted from the close proximity.)
- B738/A321, Prague Czech Republic, 2010 (On 18 June 2010 a Sun Express Boeing 737-800 taxiing for a full length daylight departure from runway 06 at Prague was in collision with an Airbus 321 which was waiting on a link taxiway leading to an intermediate take off position on the same runway. The aircraft sustained damage to their right winglet and left horizontal stabiliser respectively and both needed subsequent repair before being released to service.)
- Vehicle / E190 / E121, Jersey Channel Islands, 2010 (On 1 June 2010, an Airport RFFS bird scaring vehicle entered the active runway at Jersey in LVP without clearance and remained there for approximately three minutes until ATC became aware. The subsequent Investigation found that the incursion had fortuitously occurred just after an ERJ 190 had landed and had been terminated just as another aircraft had commenced a go around after failure to acquire the prescribed visual reference required to continue to a landing. The context for the failure of the vehicle driver to follow existing procedures was found to be their inadequacy and appropriate changes were implemented.)
- The “Barn Door” Effect by C. West, Ph.D., NOAA - a paper about pilots’ propensity to continue approaches to land when closer to convective weather than they would wish to get while en route.