Virgin Australia B738 near Adelaide on Nov 7th 2014, speed decay during climb remained unnoticed

Last Update: June 10, 2015 / 15:57:50 GMT/Zulu time

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Photo of Virgin Australia VH-VUR, Boeing 737-800 — Virgin Australia VH-VUR, Boeing 737-800 (Photo credit: Simon_sees / Flickr / License: CC by)

Incident Facts

Date of incident
Nov 7, 2014

Classification
Report

Airline
Virgin Australia

Flight number
VA-1385

Departure
Adelaide, Australia

Destination
Brisbane, Australia

Aircraft Registration
VH-VUR

Aircraft Type
Boeing 737-800

ICAO Type Designator
B738

A Virgin Australia Boeing 737-800, registration VH-VUR performing flight VA-1385 from Adelaide,SA to Brisbane,QL (Australia), was climbing out of Adelaide. The crew used LNAV and VNAV until climbing through FL250, then changed to LVL CHG. The aircraft continued to climb at 280 KIAS, the autopilot changed from maintaining a fixed IAS to a fixed mach number at FL265 as per design using mach 0.69 matching 280 KIAS at FL265. The aircraft continued to climb to FL390 when the captain noticed that the indicated airspeed had decayed to the minimum maneouvering speed of 216 KIAS and initiated an acceleration to mach 0.77. The aircraft continued for a safe landing at Brisbane without further incident.

The ATSB released their final report releasing following safety message:

For flight crew, this incident highlights the importance of continued auto-flight system mode and aircraft energy state awareness. The incident also highlights the manner in which various distractions have the potential to adversely affect such awareness. For operators, the incident highlights the importance of robust auto-flight management procedures, supported by appropriately focussed crew training and standardisation.

In 2010, the European Aviation safety Agency issued a Safety Information Bulletin on the subject of Flight Deck Automation Policy – Mode Awareness and Energy State Management. The bulletin included a number of recommendations to operators addressing automation policies, procedures and training. A copy of the bulletin is available at . Operators of highly automated aircraft are encouraged regularly review their own automation policies, procedures and training in the context of the recommendations included in the bulletin, and with the benefit of lessons learned from this and similar incidents..

The ATSB wrote: "During this occurrence, the crew noticed that the airspeed was near the minimum manoeuvre airspeed on the PFD, and noticed the ‘buffet alert’ message on the CDU scratchpad, and responded accordingly. Other more salient system alerts and levels of protection were available had the crew not responded when they did, and the airspeed had continued to reduce. These include an aural ‘airspeed low’ alert and, following further airspeed reduction, a stick-shaker system. Under some conditions the auto-flight system may also command a reduction in the aircraft pitch attitude (accepting a reduction in the rate of climb in return for airspeed management), if the airspeed reaches the minimum manoeuvre airspeed."

The ATSB summarized crew statements: "During the operator’s investigation into the incident, the crew commented that a number of distractions may have contributed to the incident. The crew commented that sun glare was particularly problematic – the glare was directly through the windscreen for the duration of the climb. The crew also commented that they may also have been distracted by air traffic control and cabin-related communication requirements, and other air traffic in their vicinity. Additionally, both pilots consumed breakfast during the climb (at separate times), which may have provided a source of distraction."