Serious incident Boeing 777-236ER G-YMMR, 11 Jun 2021
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ASN Wikibase Occurrence # 264651
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Time:13:27 UTC
Type:Silhouette image of generic B772 model; specific model in this crash may look slightly different    
Boeing 777-236ER
Owner/operator:British Airways
Registration: G-YMMR
MSN: 36516/771
Fatalities:Fatalities: 0 / Occupants:
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:London-Heathrow Airport (LHR/EGLL) -   United Kingdom
Phase: Take off
Nature:Passenger - Scheduled
Departure airport:London-Heathrow Airport (LHR/EGLL)
Destination airport:Accra-Kotoka Airport (ACC/DGAA)
Investigating agency: AAIB
Confidence Rating: Accident investigation report completed and information captured
A British Airways Boeing 777-200, registration G-YMMR performing flight BA-81 from London Heathrow (UK) to Accra (Ghana), was accelerating for takeoff from Heathrow's runway 27L when the crew rejected takeoff at about 80 KIAS due to unreliable air speed indications on all three pitot systems. The aircraft slowed safely and returned to the apron.

A replacement Boeing 777-200 registration G-YMMA reached Accra with a delay of about 5:15 hours.

The AAIB reported the occurrence was rated a serious incident and is being investigated, all three pitot systems provided unreliable air speed indications. In addition, British Airways had two more unreliable air speed events involving an A320-200 with 2 blocked pitot tubes and an A320-200N with one blocked pitot tube in about the same time frame.

The aircraft had been on the ground at LHR for five days before the occurrence and resumed service on 18 June 2021.

The AAIB indicated that two similar events occurred at a similar time, involving:
- a Boeing 777-200ER at London Heathrow Airport - Suffered rejected takeoff due to unreliable air speed indications on all 3 systems.
- an Airbus A320-251N at London Heathrow Airport - Returned to stand with an air data issue;1 of the 3 pitot tubes blocked.

UPDATE: The AAIB investigation into the incidents was published 27 January 2022, and the following is an excerpt from it..

"Between 9 June 2021 and 19 July 2021, several aircraft suffered from abnormal pitot/static system events, two of which resulted in rejected takeoffs. The AAIB investigation identified the cause to be the nesting activity of certain species of wasps and bees within pitot probes. This report addresses the likely reasons as to why there was a concentration of such events over a relatively short period of time.

Although Heathrow Airport and the surrounding area was the focus for these occurrences, detailed information on the environmental factors is provided for the operators of airfields at other locations to take into consideration. Safety action has been taken by the CAA and those airline operators affected to reduce the risk of reoccurrence by introducing additional inspections and changes to the use of pitot covers. In addition, the airport operator is updating its environmental hazard management plan to take into account the findings of this investigation".


1. AAIB Final Report:



Revision history:

27-Jun-2021 12:12 harro Added
27-Jun-2021 12:16 harro Updated [Time, Aircraft type, Registration, Cn, Other fatalities, Location, Source, Narrative]
27-Jun-2021 12:17 harro Updated [Category]
27-Jun-2021 20:47 Dr. John Smith Updated [Source, Narrative]
27-Jun-2021 21:02 Dr. John Smith Updated [Source]
27-Jan-2022 21:37 Dr. John Smith Updated [Source, Embed code, Narrative]
27-Jan-2022 21:41 Dr. John Smith Updated [Embed code, Narrative]
06-Feb-2022 20:55 Dr. John Smith Updated [Embed code]

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