Eastern Australia DH8B at Sydney on Nov 8th 2022, radar altimeter failure, problems with both engines, brakes fire

Last Update: February 20, 2024 / 16:30:15 GMT/Zulu time

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Photo of Eastern Australia Airlines VH-TQS, De Havilland DHC-8-200 Dash 8 — Eastern Australia Airlines VH-TQS, De Havilland DHC-8-200 Dash 8 (Photo credit: ahisgett / Flickr / License: CC by)

Incident Facts

Date of incident
Nov 8, 2022

Classification
Incident

Airline
Eastern Australia Airlines

Flight number
QF-2265

Departure
Lord Howe Island, Australia

Destination
Sydney, Australia

Aircraft Registration
VH-TQS

Aircraft Type
De Havilland DHC-8-200 Dash 8

ICAO Type Designator
DH8B

An Eastern Australia Airlines de Havilland Dash 8-200 on behalf of Qantas, registration VH-TQS performing flight QF-2265 from Lord Howe Island,NS to Sydney,NS (Australia) with 24 passengers and 4 crew, was on approach to Sydney's runway 34R when the crew reported the failure of the radar altimeter. During subsequent landing manual caution lights illuminated for both engines (PW123D). While taxiing towards the apron the brakes failed and caught fire prompting an emergency evacuation. There were no injuries.

On Nov 17th 2022 the ATSB reported the occurrence was rated a serious incident, a short investigation has been initiated.

On Feb 20th 2024 the ATSB released their final report concluding the probable causes of the serious incident were:

Contributing factors

- The radio altimeter failure led to the beta lockout system relying solely on the weight on wheels to prevent the activation of the beta lockout system.

- During the touchdown, in accordance with standard operating procedures, the power levers were moved into the beta range. As this occurred when the weight on wheels sensors momentarily recorded an in-air condition, the beta lockout system and engine manual condition activated. This meant that reverse thrust would not be available to assist in decelerating the aircraft during the landing and taxi.

- The increased power setting required to avoid the restricted zone while in engine manual mode combined with the long taxi, increased the amount of wheel braking required, resulting in the brakes overheating, failing and igniting.

- The operator did not provide adequate guidance on how to respond to a dual engine control unit or radio altimeter failure on the de Havilland Canada DHC-8-200 aircraft, leaving flight crew without sufficient resources to appropriately deal with such failures.

Other factors that increased risk

- During the evacuation of the aircraft, the Bromo Chloro di-Fluoromethane (BCF) fire extinguisher was used on a high temperature brake fire, increasing the risk of exposure to hazardous by-products.

The ATSB analysed:

Radio altimeter failure

Both the TCAS and GPWS relied on data from the RadAlt. Thus, the failure of the RadAlt resulted in the subsequent failures of the TCAS and GPWS. Further, the beta lockout system was interlinked with both the RadAlt and WoW systems to prevent the beta range from activating in-flight. This meant that once the RadAlt had failed, the beta lockout system was relying solely on the WoW indication.

Weight on wheels

The flight data showed that, in the same second the power levers were retarded to beta range, the WoW sensors recorded a momentary ‘in-air’ condition. With the system registering an ‘in-air’ condition while the power levers were in beta range, the beta lockout system activated. The activation of the beta lockout resulted in engine manual caution warnings for both engines as the ECUs reverted to manual mode. Consequently, as the ECUs were not providing the under-speed governing during ground operations, this meant that reverse thrust was not available to slow the aircraft during the landing and subsequent taxi.

Brake failure

With both engines in manual mode and the requirement to avoid the ground operating restricted range, the flight crew had to manually advance the power levers on both engines to an increased propeller speed above 780 RPM. This subsequently increased the amount of wheel braking required.

The flight crew were able to safely stop the aircraft at the bravo 8 holding point, after about 3.3 km of taxiing. It was only after this point the braking performance deteriorated, eventually failing, igniting and initiating the evacuation. The combination of the additional burden placed on the brakes due to the increased thrust required to avoid the restricted propeller speed, as well as the length of the taxi with a downhill component, likely both contributed to the brakes overheating then failing, and igniting.

Operator guidance – engine manual warning and RadAlt

After the failures of the GPWS, TCAS and RadAlt, the flight crew consulted the DHC-8-200 QRH finding guidance for the TCAS and GPWS failures, but none for the RadAlt failure. Had the QRH contained information regarding the flow on effects of the RadAlt failure on the beta lockout system, it was likely the flight crew would have delayed the movement of the power levers into beta range during the landing until weight on wheels was assured.

Similarly, when the flight crew observed the engine manual caution warnings on both engines, they again consulted the QRH, finding guidance for only a #1 or #2 engine manual warning. Had the QRH provided additional guidance on dual engine manual cautions, the flight crew could have safely terminated the taxi at the bravo 8 holding point, or at any point prior, likely avoiding the brake failure, fire, and subsequent evacuation.

Fire extinguisher usage

Before evacuating the aircraft, the FO consulted the QRH and in accordance with the checklist exited the aircraft with the BCF fire extinguisher. Cognisant of the proximity of evacuating passengers, and unaware of the response time of the emergency services, the FO elected to deploy the BCF on both brake fires. Although no-one was adversely affected in this occurrence by the use of the BCF fire extinguisher, their use on high temperature metal fires (such as a brake fire on the DHC-8-200 as noted in the Aircrew Emergency Procedures Manual), can result in the production of a number of toxic fumes.