VOCA

An aviation researcher, writer, aviation participant, pilot & agricultural researcher. Author of over 35 scientific publications world wide.

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Canberra 737

Incident of 737 on approach to Canberra airport [RWY 35] 2012

The incident reported by ATSB bears reading, where a fully crewed 737 has the weather [indicating IFR conditions], the ILS unavailable and an alternate approach required.

The available approaches for RWY 35 are as follows, when the ILS is un-available:

 1. VOR [Air Services]VOR RWY 35 CB

2. RNAV [Air Services]

RNAV-Z RWY 35

The report leaves a bit to be desired, with little discussion or direction on matters such as the Fatigue Management system, or operational continuance with flight under the IFR.

From the report:

Other than the high workload and possible tiredness, a factor in the crew initially not recognising the altitude deviation was probably their expectation that the automatic flight system was correctly controlling the descent profile in VNAV, conforming to the flight management computer waypoint altitude constraints. Once the flight crew resumed a crosscheck of distance against altitude it became apparent that the aircraft was low on profile and corrective action was taken.

Question is:

Why did the crew not immediately initiate a go-around, as is required under IFR rules, when the minima is not met??

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and as picked up by Ben Sandilands:

Saturday, July 6, 2013

How Qantas could have caused an early election

 

It was a dark and rainy night back on 12 February 2012 when the tired pilots of a Qantas 737-400 making a landing approach to Canberra Airport busted their safe minimum altitude and came within 1100 feet of the unseen big hills below them.

Depending on who might have been at the pointy end of the Qantas flight, some of the precursors for a by-election or two, or the fall of a minority government, flickered briefly into place, but as the ATSB recounts in its investigation of a ‘descent below safe minimum altitudes’ by the Qantas flight, a crash was never likely.

The crew realised they had stuffed up the approach and corrected their trajectory, and the altitude breach did not trigger an enhanced ground proximity warning alert, which would have told them to pull up in no uncertain terms had the situation become perilous.

All that taken on board, the ATSB report, the detailed one, not the patsy summary for lazy media,  is not a great reflection on the conduct of the flight, or an Qantas, which is to the man or woman on its board and in its senior management, personally responsible under Australian law for the maintenance of safety of flight by the airline.

The pilots of the 737 inadvertently left the automatic flight system in the level change mode rather than the vertical navigation mode specified by the operator for such approaches.

The ATSB found that “While in that mode the flight crew had selected an altitude lower than the applicable minimum safe altitude, with the effect that unless the crew intervened, the aircraft would descend to that lower altitude. The flight crew then allowed the aircraft to continue descending in the level change automatic flight mode through the segment minimum safe altitude, reflecting a temporary loss of situation awareness.”

The jet, with around 168 seats, was flown below its minimum safe altitude for 37 seconds at a speed of more than 180 knots. But it was all imperfectly safe, to paraphrase the ATSB, in that the risk of hitting anything at electorally significant velocity, was acquitted by the pilots realising their error.

The main ATSB finding is that pilots should be more careful.

The short yet detailed report can be read by following the download links on this summary page.  It is a very interesting read. You will undoubtedly agree that pilots should be more careful, but pilot performance requires management performance too, meaning you may also wonder why the ATSB wasn’t more specific or prescriptive about such matters as fatigue, work loads, and flight standards oversight in Qantas.

You only get so many chances to lose your way in the dark on an approach into Canberra, even if only for 37 very long and fast seconds.