On June 18th, we reported on a British Airways 787 suffering a nose gear collapse while on stand at London Heathrow Airport. With nearly a month having passed, the UK’s Air Accidents Investigation Branch (AAIB) has issued a special bulletin regarding the accident, giving us additional insight into how this accident happened.

british airways 787 gear collapse
A cargo loader positioned at the forward cargo hold received minor injuries in the incident. Photo: AAIB

What happened to G-ZBJB?

The British Airways 787-8 registered G-ZBJB was being loaded with cargo in preparation for a flight to Frankfurt on June 18th. While being prepared for its journey, crews were performing a “Dispatch Deviation Guide” (DDG) procedure- a procedure that permits the operation of an aircraft, under specific conditions, with particular instruments or functions inoperative for a period of time, until rectification can be made.

In this case, the AAIB states that the DDG procedure required the cockpit landing gear selection lever to be cycled with hydraulic power applied to the aircraft. It was at this time that human error caused the accident, with the AAIB stating the following (underline added for emphasis):

“To prevent the landing gear from retracting, the procedure required pins to be inserted in the nose and main landing gear downlocks. However, the NLG [nose landing gear] downlock pin was installed in the NLG downlock apex pin bore which was adjacent to the correct location to install the downlock pin. When the landing gear selector was cycled the NLG retracted.”

The language is certainly on the more technical side. But if we were to sum it up in layman’s terms, a critical locking pin was inserted into the wrong hole. With the pin absent from the necessary location, the nose landing gear retracted once the landing gear selector was cycled.

british airways 787 gear collapse
A diagram contained within the AAIB special bulletin shows where the pin should be installed and where the pin was incorrectly inserted. Photo: AAIB

Authorities were aware of the potential confusion

Interestingly, it appears that this is not the first time an incident of this nature has occurred. The AAIB states that in 2018, another Boeing 787 experienced a retraction of the nose landing gear while the aircraft was on the ground. The cause was found to be an incorrect insertion of the NLG downlock pin.

As a result of this previous event, Boeing published a service bulletin instructing operators to “install an insert into the NLG lock link apex pin inner bore.” Doing so would prevent the NLG downlock pin from being inserted into the apex pin bore instead of the adjacent NLG downlock pin hole.

This procedure was mandated by an FAA Airworthiness Directive (AD) published on January 16th, 2020. However, it looks like authorities considered this to be less than urgent, providing a compliance time of 36 months (three years) from the publication date. In the case of G-ZBJB, an insert had not been installed.

787 British Airways collapse
An Airworthiness Directive (AD) had been issued to install an insert over the apex pin bore to prevent incorrect installation of the downlock pin. Photo: AAIB

Was 36 months too long?

In the end, the sudden collapse resulted in damage to the aircraft’s lower forward fuselage and engine cowlings. The aircraft passenger cabin door was also separated as it struck mobile steps on the way down, causing a cargo loader to be injured.

For its part, British Airways had issued a “Technical News leaflet 10279007 – ‘787 NLG Downlock Pin Installation’ on April 9th, 2020. This leaflet showed the correct and incorrect position of the NLG downlock pin and referenced the FAA Airworthiness Directive and the Special Bulletin. This was also re-issued on December 9th, 2020.

As a result of this accident, the airline has since re-issued the technical news leaflet- doing so the day after the June 18th incident. The AAIB states that BA is now planning to “expedite the incorporation” of the airworthiness directive to install the insert.

Commenting on the incident, BA told Simple Flying:

“Safety is always our highest priority and we are working closely with the AAIB on the continuing investigation.”

The AAIB notes that, in addition to this special bulletin, a final report will be published in due course.

Who’s at fault?

Was the FAA’s 36-month compliance window too long? Did BA do its enough by issuing two technical news leaflets? Can the design be changed and/or an insert be installed by Boeing during manufacturing to firmly prevent this confusion in the future? Or was it simply down to one person making a critical mistake?

There are a lot of questions from this incident, with a lot to think about. Let us know what you think by leaving a comment.

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