Created Tuesday, Jun 21st 2022 23:16Z, last updated Tuesday, Jun 21st 2022 23:16Z
A Qantas Airbus A330-200, registration VH-EBC performing flight QF-575 from Sydney,NS to Perth,WA (Australia), was climbing out of Sydney when the crew received indication of a hydraulic leak, stopped the climb at FL230 and returned to Sydney for a safe landing on runway 34L about 45 minutes after departure. The aircraft vacated the runway and stopped on the parallel taxiway. About 20 minutes later the aircraft was towed to the apron. Already on the apron mist began to reduce visibility in the cabin, passengers began to complain about sore eyes and itchy throats. Once the tow stopped at the stand, the captain initiated an evacuation via slides, emergency services responded. Two passengers were taken to hospitals with injuries received during the evactuation.

The airline confirmed the aircraft was evacuated at the gate. It appears hydraulic fluid entered the air conditioning systems. Two passengers were taken to hospitals, a number of passengers complained about sore eyes and itchy throats but declined treatment.

The ATSB have opened an investigation.

Passengers described a pungent odour developed on board before the aircraft was evacuated. Passenger photos indicated visibility on board reduced due to haze/mist.

On Dec 25th 2019 the ATSB reported about 30 minutes into the flight the crew identified an issue with the green hydraulic system. The captain decided to return to Sydney. Due to the green hydraulic failure no nose gear steering was available. The aircraft landed safely, vacated the runway and stopped to wait for the tow, the aircraft was towed to the gate. Soon after the APU was turned on, mist was observed on the flight deck and in the cabin. The captain initiated an evacuation via the airbridge and 3 slides. One passenger using the escape slides received serious, two other passengers also using the escape slides received minor injuries. A subsequent examination of the aircraft revealed hydraulic fluid had leaked from the green hydraulic system.

On Jun 22nd 2022 the ATSB released their final report concluding the probable causes of the accident were:

Contributing factors

- The rudder servo hydraulic system pressure hose ruptured in flight, depleting the green hydraulic system of fluid, which necessitated a return to Sydney.

- After the auxiliary power unit (APU) was started and bleed selected on, and the aircraft was towed back to the terminal, the leaking hydraulic fluid was ingested into the APU air intake.

The atomised hydraulic fluid, which appeared as haze, mist or smoke, was then distributed into the cabin and flight deck through the air conditioning system, resulting in the captain deciding to evacuate the aircraft.

- A number of passengers evacuated using the escape slides in a manner that increased the risk of injury (for example, on their knees, lying down or sitting before sliding, or with hands on the slides). Of the 93 passengers that used the escape slides to exit the aircraft, one was seriously injured and 5 received minor injuries.

Other factors that increased risk

- Although some cabin crew members had detected unusual smells both before and after the aircraft had been towed back to the terminal, they did not pass this information on to the flight crew prior to the captain’s decision to initiate an evacuation.

- Although some of Qantas’s A330 aircraft were fitted with an emergency evacuation signal, the emergency evacuation checklist located in the flight deck for these aircraft did not include the use of the evacuation signal. In addition, there was no documented procedure that detailed when the evacuation signal should be used by cabin crew.

- A cabin crew member did not open an available exit even though they had observed that there were no signs of smoke, fire or obstruction outside the aircraft. Rather, they assumed that there was fire outside due to haze/smoke being visible inside the cabin.

- During the evacuation, one cabin crew member did not assess outside conditions properly and 2 cabin crew members did not continue to check exit availability, instead directing passengers to the available aerobridge(s).

- The aircraft evacuation occurred at a time when cabin crew members had completed their shut-down duties and the doors had all been disarmed, with an aerobridge already connected to the aircraft. As a result, 2 exit doors were opened in the disarmed mode. Although one of these exits was then armed and reopened and the slide deployed, the other exit remained open without the slide deployed and was declared blocked.

- Qantas’s cabin crew recurrent training did not include any situation whereby a disarmed door would have to be rearmed in an emergency. This increased the likelihood that a door would be opened without the escape slide deployed, reducing the number of available exits. (Safety issue)

- Qantas’s method of briefing passengers provided limited and inconsistent information about how to use the escape slides safely and what to do with cabin baggage in an emergency. (Safety issue)

- Qantas's cabin crew primary evacuation commands did not include phrases such as 'leave everything behind' and 'jump and slide'; instead, these phrases were optional. Consequently, passengers would generally not receive specific guidance until they reached an exit, which would likely slow down the evacuation. (Safety issue)

- Some passengers evacuated utilising the slides and aerobridges carrying their cabin baggage. As a result, the evacuation was delayed and the risk of injury to themselves and others was increased.

- Following the evacuation, the cabin crew did not assist the passengers who had evacuated using the slides on the tarmac (as required by Qantas’s procedures).

- Following the evacuation, the passengers were cleared from the cabin but the cabin crew and other staff members re-entered the cabin prior to the aircraft being deemed safe by emergency services (as required by Qantas’s procedures).

- Qantas did not have a procedure for a rapid disembarkation, or other similar procedure that would effectively enable rapid deplaning at a slower and more controlled pace than an emergency evacuation. Therefore, the only option for rapid deplaning was an emergency evacuation utilising slides, which unnecessarily increased the risk of injuries in some situations. (Safety issue)

Other findings

- Just after the cabin crew at the rear of the aircraft were alerted to the haze/smoke in the cabin, they completed a verbal review of evacuation procedures together, which included discussion about the need to rearm their doors if an evacuation was required. As a result, they were prepared for the evacuation, rearmed their doors when the evacuation command was given, and successfully deployed both escape slides.

The ATSB analysed:

Hydraulic hose failure

The source of the hydraulic issue related to the loss of hydraulic fluid from a ruptured green system rudder servo hydraulic hose. Materials analysis conducted by the manufacturer indicated that the hose failure was due to a combination of corrosion and fatigue cracking of the stainless streel braid. Once the stainless steel braid failed, this left the inner Teflon hose structurally unsupported, resulting in high pressure hydraulic fluid rupturing the inner Teflon hose. This occurrence was the operator’s second occurrence involving a failure of the same hose type, fitted to the same position on 2 different aircraft with a similar age, flight hours, and cycles. Those occurrences were 6 months apart on 2 of the oldest A330s in the operator’s fleet. A similar failure had occurred on a yellow system hose on an aircraft of the same age involving another operator.

The aircraft manufacturer did mandate a calendar time replacement of some other hydraulic hoses (located in the wheel wells of the aircraft) that had a higher failure rate. However, the green system rudder servo hydraulic hose was not a mandatory replacement. Rather, it was an oncondition part that either had to have an identified visual defect or fail before it was required to be replaced. The hose had been visually inspected about 5 months prior to failure. However, the identification of any defect other than a hydraulic leak was not likely as the failed hose did not have any visual defects externally, even after it had failed.

Although the failure of the same hose on 2 different aircraft in the same fleet may indicate an underlying issue, there was not enough worldwide data to indicate an emerging trend to warrant a mandatory calendar replacement of the part. That said, there is nothing preventing individual operators from introducing a replacement program based on their own historic in-service fleetwide analysis.

Hydraulic fluid ingestion into the APU

The flight crew were unaware that there was hydraulic fluid leaking into the tail cone area of the aircraft and out onto the lower surface of the empennage. Engineers who inspected the aircraft after landing, and prior to it being towed to the terminal, did not notice any leaking hydraulic fluid on or around the aircraft. It is possible there was limited hydraulic fluid present during these inspections, and more fluid was later forced from the failed hydraulic hose as the aircraft was turned to park at its allocated gate, with the nose-wheel hydraulic actuator movement pushing residual fluid out.

The hydraulic fluid from the hose leak at the rudder servo ran down the tail and was ingested into the open APU air intake. The APU was started and the bleed air selected on while the aircraft was on the taxiway, 22 minutes prior to the aircraft arriving at the terminal. About 2 minutes after the aircraft stopped at the terminal, the low pressure suction at the APU air intake drew hydraulic fluid into the APU load compressor, enabling the air conditioning system to deliver atomised hydraulic fluid to the aircraft flight deck and cabin.

The aircraft was fitted with an air intake diverter and fluid gutters to minimise the likelihood of fluid entering the APU air intake. These features would prevent fluid intake in most cases when the aircraft was on the ground. No significant fluid appeared to enter the air intake while the aircraft was stationary on the taxiway (for 11 minutes after the APU was started) and while it was being towed (about 11 minutes). However, as evidenced in this case and the other similar serious incident involving an A330 in 2014, the diverter and gutters can be bypassed by leaking hydraulic fluid in some situations when the aircraft is stationary on the ground. In the case of VH-EBC, the wind direction when the aircraft was parked at the terminal may have assisted the hydraulic fluid ingestion (the wind was blowing from the aft to the front of the aircraft when parked).

Communication between the cabin and flight crew

The cabin crew members at the L1 and L2 doors reported smelling something unusual when the aircraft had stopped on the taxiway, and during the tow to the terminal. When the aircraft arrived at the terminal and the cabin crew commenced the procedure to disarm the doors, the cabin crew member at L3 reported that they could smell ‘dirty socks’; however, they did not communicate this to the CSM, instead reporting only about the haze that could be seen in the cabin. The FO had also smelt something unusual and reported this to the captain, however they had not provided the same descriptions as the cabin crew.

It is vitally important that cabin crew provide the flight crew information about unusual smells in the cabin with as much detail and common terminology as possible (such as using an odour descriptor). If the flight crew on this occasion had been provided with information that there was an unusual smell (particularly one that the CSM had associated with a hydraulic system problem or one which may have indicated a fumes event), this may have raised the threshold for considering the relevance of the smell in relation to the hydraulic event.

Regardless of the source of the unusual odour (it may not have been related to the hydraulic leak), this information may have prompted the flight crew to turn the APU bleed air off, as this action forms part of the smoke/fumes procedure. If the APU bleed had been turned off this would have resulted in very limited hydraulic fluid mist contamination of the aircraft cabin.

Aircraft evacuation

Use of evacuation signal

The captain issued the evacuation command via the public announcement (PA) system, stating the required words (‘evacuate, evacuate, evacuate’). The announcement was effective in alerting the cabin crew and passengers of the need to evacuate the aircraft.

The operator’s procedure required a captain to initiate an evacuation using all available means, which in this case included the use of the emergency evacuation signal (alarm) that was fitted to VH-EBC as well as making the PA. The use of the evacuation signal is a secondary method to alert crew and passengers that there is a need to evacuate the aircraft, which provides additional assurance that passengers and crew are made aware of a need to evacuate in case the PA command is not fully effective.

In this case, the captain did not activate the emergency evacuation signal. Not all of the other A330 aircraft in the operator’s fleet had the evacuation signal fitted. In addition, the Quick Reference Handbook (QRH) located in the flight deck of VH-EBC did not include the use of the evacuation signal in the evacuation checklist, even though this was in the operator’s other operational documents for flight crew. Therefore, even if the captain referred to the checklist, they would have had to recall that they were on an A330 that had this function fitted.

The emergency evacuation signal could also be activated on the flight attendant panel in the cabin on VH-EBC. However, there was no procedure detailing when the cabin crew should ensure the signal was activated. This removed an additional redundancy. In situations where a flight crew did not or could not activate the signal, the cabin crew will be unlikely to activate it without a procedure that details when they should do so.

Decision to use exits

When the captain ordered the evacuation, they did not provide any additional information to the cabin crew about the exits to be used during the evacuation. That is, the captain had not used their powers under Civil Aviation Regulation 145 to adjust the procedure for the specific situation (as detailed in some of the operator’s training as a suitable alternative in some cases), nor were they required to or needed to. Accordingly, it would be expected that all available exits would be utilised and passengers would be evacuated as quickly as possible as per the documented emergency procedure. The operator’s evacuation at the terminal procedure identified additional considerations when an evacuation occurred at a terminal, which included the use of stairs and aerobridges; however, this did not indicate that these options should be used instead of other available exits.

When the captain issued the evacuation command, the aerobridge was being connected to door L1, which provided an easy means of escape for passengers near that door. Of the other exits, 2 doors with slides were opened promptly at the rear of the aircraft (L4 and R4), with R3 also being available soon after (see below). L2 was connected to an aerobridge about 1 minute after the evacuation command, and R1 and R2 were not opened.

Although L2 eventually had an aerobridge connected, there was no reason that the R2 exit could not have been opened as the cabin crew member had assessed that the exit was clear on 2 occasions. They based the decision not to open the exit on an assumption but no visual evidence of an external fire, and possibly the fact that there was an aerobridge already connected at L1 and there was a flow of passengers towards that exit.

The R1 exit remained closed due to a vehicle being seen outside initially; however this exit was not reassessed for availability. The L2 exit was also not checked for availability to ensure that an aerobridge was being connected and to facilitate it being available as soon as possible.

Ultimately, most of the passengers in the front of the aircraft were directed to the L1 exit to evacuate for the first 50 seconds of the evacuation. Although using the aerobridge reduced the risk of physical injuries on this occasion, not opening available exits in an evacuation as soon as practicable can have catastrophic consequences depending on the situation.

Operation of the doors during the evacuation Two of the 4 cabin crew who opened a door with the intention to activate an escape slide did not rearm the door before opening it (L3 and R3). One of the cabin crew members then promptly closed the door, rearmed the door and opened it again to activate the slide (R3).

The cabin crew members were all trained and assessed against the operator’s published and approved procedures, and they were all qualified to operate the flight. However, the training for an evacuation at the terminal was limited. Cabin crew had practiced the procedure for an evacuation at a terminal during initial training, which identifies additional considerations such as ensuring that the doors are rearmed. Nevertheless, the cabin crew had not practiced the procedure in recurrent training for a number of years, and most of the cabin crew had not practiced the procedure since their initial training.

The operator’s procedure to open the doors in an emergency stated that they should open the door ‘ARMED’, and this implied that the cabin crew should first check the door was armed.

Reports from cabin crew advised that in their annual training and assessment, the door was always in the armed position in an evacuation scenario, and therefore it was not habitual for them to check that the door was armed prior to opening.

In comparison, the manufacturer’s procedure explicitly stated that the person should check that the door was armed before opening. It would therefore be beneficial to ensure that the procedure for opening the door in an emergency includes a step that ensures that the cabin crew check the status of the door prior to opening, and that cabin crew are trained to check that the door is armed, regardless of where an evacuation occurs.

Review of procedures after landing

Just after the cabin crew at the rear of the aircraft (L4 and R4) were alerted to the haze/smoke in the cabin, they completed a verbal review of evacuation procedures together, which included discussion about the need to rearm their doors if an evacuation was required. As a result, they were prepared for the evacuation, rearmed their doors when the evacuation command was given, and successfully deployed both escape slides.

Both the rear cabin crew members recalled utilising the silent review concept with each other just prior to the evacuation being called. The silent review is a well-known tool utilised by cabin crew during the take-off and landing stages of flight and will usually be undertaken when the no-contact phase is in place. The use of this same premise, coupled with communicating what actions were required, is a great example of the use of non-technical skills by these cabin crew members.

Cabin crew should be encouraged to mentally rehearse their procedures anytime they have been alerted to an abnormal situation, as well as during take-off and landing, and it would be advisable that crew members are reminded to remain alert to any abnormalities until everyone has safely disembarked the aircraft.

Cabin baggage and use of escape slides

Passenger safety briefing

Information about what to do with cabin baggage in an emergency and the use of escape slides was provided to passengers in a safety video (with audio and subtitles), and was supplemented by the information in the safety briefing card. However, the content provided to passengers was both limited and inconsistent in the following ways:

- The procedure to descend the escape slide safely included instructions about jumping past the girt bar, keeping legs straight with toes pointed upwards; this information was not included in the safety video. Although the briefing card had a pictorial that could be interpreted as having a requirement to jump and slide with toes pointed upwards, it could not be determined to what extent passengers had this interpretation.

- The safety video showed a passenger sitting and then sliding, which is not the recommended means of using an escape slide. As research has shown, this method (rather than jumping first) can cause delays in an evacuation.

- The safety video showed a passenger leaning back with their hands on their knees, rather than leaning forward, which is the safest means of use.

- The briefing card showed a person jumping and crossing their arms to descend the slide. Although this would be an acceptable position when sliding, it was not consistent with the operator’s procedure or the safety video.

- The safety video depicted a passenger putting their cabin baggage next to the slide as they sat down to descend the slide. However, it is obviously preferable that passengers do not bring cabin baggage to the exits at all.

- The briefing card showed a small pictorial of a bag with a circle and a line through it to indicate to passengers that cabin baggage should not be taken when exiting; this was the only reference to the requirement to leave bags behind on the briefing card.

- The in-flight announcements (just prior to landing) did not include a reminder to leave cabin baggage behind in an emergency.

- There was no information provided about how to descend the escape slide safely with infants and children, either in the information provided to passengers or in the operator’s procedures for cabin crew.

Although there is no guarantee that passengers will attend to safety information provided to them in pre-flight safety briefings, there have been a number of developments in the utilisation of audio/visual presentations (video) by operators, using entertainment in an attempt to gain passenger attention. However, there has been no research that has proven that this approach leads to safer outcomes in emergencies.

Regulatory requirements dictate what information must be provided to passengers orally and in a written format, and in this case those minimum requirements were met. However, the operator’s safety video provided the information in differing contexts outside of the aircraft environment. For example, it utilised a slide at an amusement park rather than an actual aircraft emergency evacuation slide. In this part of the safety video, the audio and subtitles provided information about the use of the escape slides and the requirement to leave cabin baggage behind, but the visual content did not match the audio information.

The majority of airlines who fly domestically in Australia do not use a safety video and are not required to do so; rather, information about cabin baggage and slide use is provided orally (using a pre-recorded announcement or a public announcement by the cabin crew) and via the safety briefing card. Utilising a video can certainly be useful in providing passengers a visual representation of actions they may be required to take. However, to be most effective, the information in the video about cabin baggage and the use of the slides should be consistent with the information given in both the safety card and the audio, and clearly outline the required actions.

Research conducted by the NTSB (2000) and the ATSB (2004) found that passengers tend not to look at the safety briefing card, and even if passengers do look at the card not all of them will understand the instructions provided. The NTSB also found that passengers believed that the safety briefing should include information on how to operate the exits and escape slides. As it cannot be guaranteed that a passenger will attend to and understand the information provided on a safety briefing card, it should only be used as a supplement to the oral briefing and not the primary source of safety information provided.

The management of passengers in an emergency situation is the last line of defence in avoiding injury and fatalities. Therefore it is important that passengers are well informed through the provision of sufficient and accurate communication about what they may be required to do. It is widely known that more knowledgeable passengers will be better equipped to react appropriately in an emergency, and that briefing passengers does in fact increase passenger survivability (Meng-Yuan, 2014). In this occurrence, the passengers were provided with information that was limited and inconsistent, and this meant that there was more reliance on cabin crew providing instructions to passengers on what to do during the evacuation.

Commands used during the evacuation

Qantas’s cabin crew primary evacuation commands to passengers did not include phrases such as 'leave everything behind' and 'jump and slide'; instead, these phrases were optional.

Consequently, passengers would generally not receive specific guidance about required actions until they reached an exit, which would likely slow down an evacuation.

Interviews with all 8 cabin crew indicated that the commands they used to instruct passengers were consistent with the core commands documented in the operator’s Aircrew Emergency Procedures Manual (AEPM), which were those they had practiced in training. However, some of the cabin crew reported that they had not utilised the ‘other recommended commands’.

It is very likely that passengers may attempt to evacuate with cabin baggage in an emergency, particularly when disembarking at a terminal, and there have been examples where confrontation with cabin crew at the exits has caused an interruption to the evacuation flow. Accordingly, it is important that cabin crew advise passengers at the beginning of the evacuation to leave everything behind. This may not stop all passengers bringing cabin baggage to the exit but may prevent some passengers from attempting retrieval, and can limit the potential number of bags brought to the exits.

In terms of escape slide use, almost all passengers will have never had the opportunity to utilise an aircraft escape slide and therefore will rely on the cabin crew to provide instruction on its use.

The passenger safety briefing and briefing card in this occurrence provided conflicting and limited information, and this made the reliance on cabin crew instructions even greater. The cabin crew reported only providing additional instruction to passengers when they reached the slide, some of which were not consistent with guidance provided by the manufacturer and others for safe and efficient slide use in an emergency, for example ‘sit and slide’, ‘get out’.

Research has shown that the trained evacuation commands used in an evacuation should be aligned with those used during certification. This is because when the aircraft is certified, the testing that is undertaken provides assurance that not only the aircraft design is effective, but also the procedural aspects such as cabin crew commands are too. Without additional testing or research, a significant change to those commands becomes an unknown in terms of their effectiveness. For example, the operator no longer requires the passengers to form 2 lines for dual lane slides and does not always use the command to jump (onto the slide).

Passenger behaviour during the evacuation

Passenger behaviour in emergencies will always be unpredictable, particularly given that many emergencies will have unique aspects. However, in several previous evacuations passengers have taken cabin baggage, even when instructed explicitly not to.

In this case it was reported that passengers were reasonably compliant when given instruction directly. Given the timing of the evacuation, where some passengers were already standing getting ready to disembark, it is also understandable that they would have already retrieved some cabin baggage. However, it was still very evident that a significant number of passengers retrieved baggage after the evacuation command, and some evacuated with cabin baggage using the escape slides. This resulted in a slower evacuation pace. In this case, the risk of harm from the fumes was less once the doors were opened and the cabin was ventilated. Therefore, there was a lower risk of incapacitation or significant effects from exposure to the atomised hydraulic fluid.

Video footage and reports from the cabin crew showed that many passengers were unaware of what to do when they used the evacuation slides. Some passengers reportedly sat and slid, and others went down the slide on their knees or were lying down. Six passengers were injured as a result of using the escape slides, with a variety of injuries reported, including friction burns to the hands. Friction burns to the hands are a result of placing hands on the slide when sliding down.

This is partly why the recommended safe slide position includes placing the arms across the chest or on the knees, the other reason is to provide stability and maintain a slower speed.

The passenger who was seriously injured could not recall any instructions prior to or during the evacuation about how to descend the escape slide. It could not be determined whether other passengers who received injuries paid attention to the information provided in the safety video, or whether they could recall the information.

Post evacuation

The operator’s procedures required that both the flight and cabin crew assist passengers on the tarmac after they have evacuated, until relieved by emergency services. On this occasion, emergency services were present when the evacuation occurred. Nevertheless, none of the cabin crew provided assistance to the passengers who had evacuated using the slides. The cabin crew, who have first aid training, may have been able to assist in attending to passengers on the tarmac, particularly those with injuries.

Cabin crew did ask the captain if they should exit via the slides, however the captain gave the cabin crew the choice of evacuating via the aerobridges. Both the cabin crew and the flight crew exited via the aerobridges, with the flight crew proceeding to the tarmac to report to the fire commander and provide assistance, before returning to the terminal.

The operator’s procedures, and the procedures of the aviation rescue fire fighting service (ARFFS), stipulated that the fire commander was required to conduct a risk assessment of the aircraft before flight crew, cabin crew and ground personnel, were cleared to re-enter. However, following the evacuation, cabin crew continued to re-enter the aircraft cabin to collect cabin baggage and other items for both passengers and other crew members. Other personnel also entered the aircraft cabin. They did so without being given a clearance that it was safe to do so.

These personnel were not equipped to re-enter the cabin, nor were they in a position to conduct an informed assessment of the risk.

Rapid disembarkation

The objective of an evacuation is to optimise the use of all available exits. The captain on this occasion commanded an evacuation believing that it was necessary to get out of the aircraft as quickly as possible. The captain was aware of haze, mist or smoke in the flight deck and cabin, was not sure of the source of the problem, and was aware that the problem was getting worse. Given this context, the captain’s decision to evacuation was appropriate.

However, to reduce the number of potential injuries related to escape slide use, a rapid disembarkation (if available) may be a suitable alternative in other situations where there may be a need to get out of the aircraft quickly, but not with the same level of urgency. This includes situations such as a fuel spill, fumes event or bomb threat where the rapid disembarkation can be upgraded to an evacuation if required.

In this case, at least some of the cabin crew were inadvertently actioning a form of rapid disembarkation/rapid deplaning procedure, as opposed to an evacuation that required all available exits to be used and the aircraft to be ‘evacuated’ as quickly as possible. Although the captain had commanded an evacuation, some of the cabin crew had assessed that there was no immediate danger in the cabin, and had decided that it was in the best interests of passengers to only use certain exits and at a slower pace.

For example, the cabin crew in the forward section of the aircraft who did not have an aerobridge connected, upon establishing a flow of passengers, did not continue to check outside their exits to determine if they were usable and instead decided to redirect passengers to the exits connected to the aerobridges. In addition, the cabin crew member at R3 changed their commands for passengers reaching the exit to sit down and slide.

This assessment by the cabin crew of less urgency did not result in any adverse outcomes on this occasion. However, without any further consultation with the flight crew, the cabin crew may not have had all the information to effectively downgrade the emergency response.

As evidenced in the operator’s training material, a captain could initiate an evacuation and nominate the use of some exits only. However, adding specific instructions to an evacuation procedure can add complexity to the situation, and the use of selected exits would be more compatible with a rapid disembarkation procedure, if available. A rapid disembarkation procedure can be upgraded to an evacuation at any time. However, it is more difficult to go the opposite way and downgrade an evacuation after it has been initiated, which also has the potential to lead to an increased number of injuries to passengers.

Having a rapid disembarkation procedure ensures that there is a broader framework for crews to use to respond to abnormal or emergency events. It also ensures that flight crew and cabin crew will be routinely trained and assessed in the use of the procedure for responding to particular types of events.

As highlighted by a number of investigation reports, accidents around the world continue to show that there is a significant risk of injury to passengers when escape slides are used. This risk is acceptable in a life-threatening situation where the alternative may be catastrophic; however in cases such as a fumes event, fuel spill or other similar situation where passengers can be disembarked in a quick but controlled manner, particularly if an aerobridge is already attached, a procedure that allows passengers to disembark quickly in a controlled manner may be preferable to prevent unnecessary injury.

Scene on board:

Evacuation almost completed:

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