Sunstate DH8D at Port Moresby on Mar 16th 2020, smoke in cockpit

Last Update: September 21, 2021 / 16:15:56 GMT/Zulu time

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Photo of Sunstate Airlines VH-QOE, De Havilland Dash 8 (400) — Sunstate Airlines VH-QOE, De Havilland Dash 8 (400) (Photo credit: Ev Brown / Flickr / License: CC by)

Incident Facts

Date of incident
Mar 16, 2020

Classification
Incident

Cause
Smoke in cockpit

Airline
Sunstate Airlines

Flight number
QF-192

Departure
Port Moresby, Papua New Guinea

Destination
Cairns, Australia

Aircraft Registration
VH-QOE

Aircraft Type
De Havilland Dash 8 (400)

ICAO Type Designator
DH8D

A Sunstate Airlines de Havilland Dash 8-400 on behalf of Qantas, registration VH-QOE performing flight QF-192 from Port Moresby (Papua New Guinea) to Cairns,QL (Australia) with 8 passengers and 4 crew, was climbing out of Port Moresby's runway 32 when the crew stopped the climb at about FL190 reporting smoke in the cockpit and returned the aircraft to Port Moresby for a safe landing on runway 32 about 24 minutes after departure.

The passengers were rebooked onto later flights via Brisbane and departed Port Moresby with a delay of about 2 hours and reached Australia before a requirement for two weeks quarantaine as result of Corona Virus prevention came into effect.

The aircraft is still on the ground about 22 hours later.

On Mar 20th 2020 PNG's AIC reported the occurrence was rated a serious incident and is being investigated by the AIC. The AIC reported about 20 minutes into the flight smoke was detected in the cabin. There were no injuries and no damage.

On Apr 17th 2020 the AIC released their preliminary report stating:

At about 01:22, during the climb and as soon as the normal After Takeoff procedures checklist was completed, the flight crew noticed the presence of a “strange smell” inside the cockpit, later described to AIC investigators as a smell similar to “dirty socks”.

The Pilot in command (PIC) indicated to the investigators that at the time the smell was detected by the flight crew it was not too strong and there was no alert or fault indication in the annunciator panel. For these reasons, they initially decided to continue climbing.

As the aircraft climbed through FL3 100, the flight crew noticed the smell appeared to increase and fumes were entering the flight deck. The examinations conducted at the initial stages of the investigation, revealed that the source of the fumes was located in the No. 2 engine compressor bleed air section.

The PIC called the cabin crew through the intercom4 and they confirmed the presence of a “strong weird smell” throughout the cabin. When the aircraft was approaching FL 150, the flight crew donned their oxygen masks and opted to return to Port Moresby and the PIC briefed the cabin crew accordingly.

At about 01:30, approximately 30 nm from Port Moresby the aircraft was levelled at FL 180. After broadcasting a PAN and obtaining the clearance from the Air Traffic Control (ATC), the flight crew commenced to return to Port Moresby, making a right turn and descending to FL 100.

During descent, the flight crew conducted the Smoke/Fumes Emergency procedure in accordance with the Quick Reference Handbook (QRH).

The flight crew levelled the aircraft off at FL 100 as it entered the Islok holding pattern. The cabin crew subsequently called the flight crew reporting smoke was entering the cabin.

As cleared by the ATC, the flight crew performed a ‘visual approach’ and landed on runway 32R. According to the PIC statement, the approach and landing were normal.

The aircraft continued its landing roll to exit the runway via taxiway Foxtrot (figure 2) where it came to a complete stop. In that position, the passengers and the crew exited the aircraft through the main door.

On Sep 21st 2021 The PNGAIC released their final report concluding the probable causes of the incident were:

The smoke/fumes that entered the cabin through the bleed air system was produced by the oil liberated at the No.3 bearing carbon seal coming in contact with hot surfaces inside the engine.

The wear-out and early fracture of the airside carbon element was believed to be caused by exudation of salt and oxidation of the air side carbon element, processes dependent of the high operating temperatures and humid environments.

The manufacturer of the engine had noted that No. 3 bearing carbon seal is likely to fracture earlier than its first overhaul shop visit as the earliest failure case reported was about 8,500 hours. At the time of the occurrence, the seal had 9,218.11 hours and had not reached the time for its first engine overhaul shop visit. The 718.11 hours more than the wear trend.

Service bulletin SB35341, issued by the manufacturer with regard to the conditions for replacement of No. 3 bearing carbon seal, did not include the wear trend of the component determined by the manufacturer as a condition or consideration for its replacement.

The PNGAIC analysed:

The investigation determined that even when the Qantas Link Aircrew Emergency Procedure Manual and Operations Manual clearly specifies that fumes caused by oil contaminated bleed air have been described as having a strong odour similar to ‘dirty socks’, the cabin crew did not make the right association between the odour and its origin. As the emergency procedures applicable for smoke and fumes in the cabin and in the cockpit ultimately require landing as soon as possible, if the cabin crew had identified correctly the origin of the odour and reported it when they initially perceived it, the flight crew would have had more time available for decision making and, possibly, a chance to cancel the flight even before take-off.

The crew identified that the fumes/smoke was entering through the bleed system, however, they were unable to identify whether it was associated with the No.1 (left) or No.2 (right) engine. The investigation could not identify any abnormal parameters from the FDR associated with operation of either engine for the flight and emergency. The No.2 engine, the actual source of fume/smoke, was operating within the normal parameters. This indicated that the cockpit engine gauge readings gave no reasonable abnormal readings that would have helped the crew to positively identify that the fumes/smoke were entering from the No.2 engine.

Additionally, at the onset of the emergency, the flight crew carried out the QRH specific procedure for “Bleed Source or Air Conditioning Suspected”. The procedure initially requires turning Bleed Air 1 off, and then to wait up to one minute for improvement. As the issue was in effect associated to Bleed Air 2, there was no improvement. Under these conditions, the flight crew is expected, as per the procedure, to turn Bleed Air 1 back on and then to turn Bleed Air 2 off, and subsequently to wait up to one minute for improvement. However, the PIC decided not to turn Bleed Air 1 back on, which in the end caused that the flight crew was not able to isolate the origin of the fault to continue with the applicable steps required by the checklist to avoid unnecessary effects on safety.

Communication

VH-QOE had declared a PAN and requested for priority return to the Jacksons International Airport.

Moresby Radar contacted Jacksons Radar and advised them that VH-QOE had declared a PAN and was returning with reported fumes in the cabin. Jacksons Radar acknowledged. However, Jacksons Radar, relaying the message to Jacksons Tower, did not provide information about the PAN. Following the query from Jacksons Tower regarding more information about the emergency situations, Jacksons Radar did not provide the clarification requested.

Following transfer of VH-QOE, Jacksons Tower called ARFF and instructed them to stand by at Taxiway Golf. Jacksons Tower called Jacksons Radar expressing concern about not receiving pertinent information requested.

Jacksons Radar asked if VH-QOE could accept a speed reduction to allow another aircraft, P2-ATF, about to join downwind, to approach ahead. The investigation determined that in the event of a potential conflict between aircraft, right of way should have been given to the emergency aircraft unless it was impracticable to do so. When the flight crew of the emergency aircraft insisted that they required priority due to smoke and fume, the Jacksons Radar advised them to stand by. The crew called back just under a minute later as they had not heard back from Jacksons Radar, and it was then that they received clearance to approach.

The fact that Jacksons Radar was able to appropriately have P2-ATF safely give way, following VHQOE flight crew’s counter-request (request to be number 1), showed that there were available options for ATC to initially allow VH-QOE to be given right of way to approach ahead of the other nonemergency traffic. The investigation determined that the request for VH-QOE to accept a speed reduction was not necessary or appropriate. This circumstance did not cause any delay or deviation to VH-QOE’s flight path.

The investigation recognises that any unnecessary distraction or diversion of attention has the potential to affect the ability of the flight crew to effectively manage time critical situations such as an urgency or emergency situations. Although it was to no significant detriment, the flight crew of VH-QOE had their attention diverted intermittently for a period of just under a minute during the approach, following Jacksons Radar’s speed reduction request.

No.2 Engine

The status of the chip detectors and free rotations of the PT, LP turbine and HP turbine spool showed that engine was operative, and the flight crew did not report any abnormal indications related to No. 2 engine parameters. According to P&WC, the No.3 bearing carbon seal was believed to be due to wearout caused by exudation of salt and oxidation of the air side carbon element The evidence of oil found on other components of the engine was an indication that, as a result of the failure of the carbon element, oil leaked through the bearing seal and went into engine’s air passage.

As the oil encountered hot surfaces, it released fumes/smoke that entered the aircraft cabin through the bleed air system.