[Peetwo]

ATSB FR: QLD Govt Airwing incident - A lesson perhaps? 

Via the Oz today:

Jet emergency sparks reform

ROBYN IRONSIDE
The Queensland Government Air Wing has introduced new training in the wake of an emergency involving the police jet.

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The Queensland Government Air Wing has introduced new training for flight crews after an Australia Day emergency involving the police jet.

On January 26, the Cessna ­Citation 560 was carrying eight people, including Police Commissioner Ian Stewart, Police Minister Mark Ryan and Fire Chief Katarina Carroll, on a flight from Brisbane to Townsville.

About 350km north of Brisbane, a series of bangs was heard from the rear of the jet and the ­pilots made an emergency ­descent from 30,000 feet to 10,000 feet.

A request was made to air traffic control for an immediate ­return to Brisbane, with the pilots deciding to bypass Bundaberg and Sunshine Coast airports.

Although the flight crew donned oxygen masks due to a mist of “acrid smoke in the cockpit”, they did not deploy passenger oxygen masks.

At the time, Mr Ryan ­described the incident as a “frightening experience” and said he was grateful for the flight crew’s professionalism, skill, calmness and reassurance.

An Australian Transport ­Safety Bureau investigation found a tiny piece of broken metal from a compressor stage rotor in the engine caused the bangs.

“The aerofoil fractured as a ­result of a fatigue crack … the exact origin of the fatigue crack could not be determined,” the ­report says.

The investigation revealed the engine and rotor were manufactured in 2001, and had completed 3126 flight hours.

No other maintenance was required to be performed on the rotor until overhaul at 3500 hours of service.

The components were sent to engine manufacturer Pratt & Whitney Canada, which formed a specialist engineering group to review the complete history of the boost rotor, and boost rotor distress.

The next meeting of the group is scheduled for next month.

The ATSB report also says the Queensland Government Air Wing has introduced a number of new training packages for flight crew, including crew resource management for all pilots and a future line operations safety audit program.

“Although some of this training was programmed, it was expedited following a review of the occurrence involving (the police jet),” the report says.

“The first tranche of crew ­resource management training was conducted prior to publication of this report.”

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& via the ATSB: 

Investigation number: AO-2018-012

report
[DownloadPDF: 246KB]
 
 

What happened

On 26 January 2018, a Cessna Citation 560 aircraft, registration VH-PSU, was conducting a business flight from Brisbane to Townsville, Queensland. VH-PSU was operated by the State of Queensland, Public Safety Business Agency, with two flight crew and six passengers.
While passing through flight level (FL) 320[1], a loud noise was heard from the rear of the aircraft, along with the smell of smoke. The flight crew made a PAN PAN[2] call to air traffic control (ATC) and requested an emergency descent and return to Brisbane. The aircraft returned to Brisbane for an emergency landing and landed without incident.
An examination of the Pratt & Whitney Canada JT15D-5D engine, using borescope inspection, revealed the low pressure (LP) compressor (boost) rotor had lost an aerofoil and sustained some damage.

Operator’s investigation

Passing through FL320 on climb, the flight crew experienced (both heard and felt) a series of bangs from the rear of the aircraft. The pilot monitoring[3] (PM) immediately saw and smelt a slight mist of ‘acrid’ smoke in the cockpit. The PM donned his oxygen mask, immediately made a PAN PAN call to ATC and requested an immediate return to Brisbane and emergency descent. An immediate examination of engine and other system parameters indicated no other abnormalities. The pilot flying (PF) commenced the descent and turn back in accordance with ATC instruction, however, as he did not sense any smoke he did not immediately don his oxygen mask. This was a decision made so that he could maintain communications with ATC. Once satisfied that any immediate communications were carried out, he donned his mask and both crew kept their masks on until an altitude of 10,000 ft above mean sea level was reached. The PF elected not to deploy the passenger oxygen masks as there was no indication of smoke subsequent to that first noticed by the PM.

During the descent, the crew discussed the options of landing at Bundaberg or Sunshine Coast airports, but they were discounted in favour of Brisbane.

It was likely that the reduction in power necessitated by the emergency descent eliminated the smell and visual evidence of the smoke. However, the PM reported a very brief re-occurrence of the odour when power was reapplied upon gear extension at commencement of the approach into Brisbane.

Interviews with the crew after the occurrence revealed some inconsistencies in their recollections of the event, including what actions were immediately taken by whom. The inconsistencies had no direct impact on the safe outcome of the flight.

Examination of the aircraft in Brisbane revealed that the cause of the loud bangs was the failure of one of the aerofoils of the integrally bladed LP compressor (boost) stage rotor, which then exited the engine via the usual gas flow. Small globules of molten metal were found in the exhaust.

The engine was removed from the aircraft and sent to the owner[4] for initial disassembly. The relevant sections of the LP compressor were forwarded to the manufacturer in Canada for further examination and determination of the blade failure mechanism.

MTF...P2