HiFly A343 at Darwin on Feb 28th 2012, hard landing due to microburst

Last Update: August 3, 2012 / 13:50:10 GMT/Zulu time

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Incident Facts

Date of incident
Feb 28, 2012

Classification
Report

Cause
Hard landing

Airline
HiFly

Departure
Sydney, Australia

Destination
Darwin, Australia

Aircraft Registration
CS-TQM

Aircraft Type
Airbus A340-300

ICAO Type Designator
A343

A HiFly Airbus A340-300 on behalf of Royal Australian Air Force, registration CS-TQM performing charter flight ASY-15 from Sydney,NS to Darwin,NT (Australia) with 116 passengers and 8 crew, was on approach to Darwin's runway 29 when the crew observed heavy rain at the threshold of the runway. Upon query ATC reported a storm extending to the east was crossing the runway and provided winds were from 360 degrees at 5 knots at the departure end of the runway and a tailwind at 5 knots at the threshold. The crew briefed the missed approach procedure in case the conditions deteriorated. On short final the rain increased, the first officer (ATPL, 17,500 hours total, 6,000 hours on type) requested the wind screen wipers to high, the captain (ATPL, 11,800 hours total, 769 hours on type), the sink rate increased. At 55 feet AGL the engines were set to maximum continuous thrust to arrest the sink rate, at 25 feet AGL the engines were selected to idle to initiate the flare. The rain intensified further reducing visibility, the aircraft touched down on the runway producing a vertical acceleration of +2.71G and rolled out safely. The crew reported heavy rain and marginal conditions.

The ATSB released their final report in their monthly bulletin reporting that the vertical acceleration encountered required a hard landing inspection, which revealed a crack in the left hand engine's rear attachment bolt retainer. A causal link between the hard landing and the crack could not be established.

The ATSB reported that according to flight data recorder data the sink rate reduced to about 300 fpm following the thrust increase at 55 feet AGL. Two large nose down inputs followed by full elevator back pressure inputs occurred between 34 feet AGL and touch down, the aircraft touched down with a tail wind component of 18 knots at a rate of descent of 783 feet per minute.

The ATSB released their safety message reading: "Microbursts can create a severe hazard for aircraft operating within 1,000 ft of the ground. After flying into a microburst, it is common for the aircraft to encounter a headwind followed by a downdraft and tailwind. Some important characteristics of microbursts are:

- They are typically less than 1 mile in diameter, however the downdraft and subsequent horizontal outflow can extend to about 2.5 miles in diameter.

- The downdrafts can be as strong as 6,000 ft per minute and horizontal winds can be up to 45 kts.

- They may be embedded in heavy rain associated with a thunderstorm or in light rain in benign appearing virga.

- Individual microbursts seldom last longer than 15 minutes."