Annex 6 to the Convention of International Civil Aviation did not mandate the fitment of flight recorders for passenger-carrying aircraft under 5,700 kg. Consequently, the determination of factors that influenced this accident, and numerous other accidents have been hampered by a lack of recorded data pertaining to the flight. This has likely resulted in important safety issues not being identified, which may remain a hazard to current and future passenger carrying operations.
The ATSB is issuing the following recommendation:
The ATSB notes the International Civil Aviation Organization’s (ICAO) Flight Recorder Specific Working Group’s consideration of mandating the fitment of lightweight recorders in passenger-carrying aircraft with a maximum take-off weight less than 5,700 kg. While the group determined that retrofitting such devices to existing aircraft may present challenges and was unlikely to be achieved, the group has committed to continue discussions on airborne image recorders. In acknowledgement of these ongoing discussions, but noting that no safety actions have yet been taken to reduce the risk associated with this safety issue, it has been closed, not addressed.
The Australian Transport Safety Bureau recognises that the International Civil Aviation Organization has developed technical standards for lightweight recorders and airborne image recorders. However, despite the known benefits for the identification of safety issues, the fitment of such devices for passenger-carrying aircraft with a maximum take-off weight less than 5,700 kg is not mandated. The Australian Transport Safety Bureau recommends that the International Civil Aviation Organization takes safety action to consider the safety enhancement of these devices to passenger-carrying operations.
I wish to refer to your letter dated 27 January 2021, reference 2021-005, related to an accident involving a de Havilland Canada DHC-2, Registration VH-NOO, on 31 December 2017 at Jerusalem Bay (Hawkesbury River), New South Wales, Australia. The Final Report (AO-2017-118) contains a safety recommendation addressed to the International Civil Aviation Organization (ICAO) as follows:
AO-2017-118-SR-048 “The Australian Transport Safety Bureau recommends that the International Civil Aviation Organization takes safety action to consider the safety enhancement of these devices to passenger-carrying operations.”
ICAO would like to inform you that the Flight Recorder Specific Working Group (FLIRECSWG) of the Flight Operations Panel (FLTOPSP) is currently considering a similar subject. The Air Navigation Commission (ANC) tasked the FLIRECSWG to review Annex 6 — Operation of Aircraft, regarding audio recordings by means of lightweight flight recorders and propose amendments as necessary. Annex 6 already contains provisions for flight recordings for “all turbine-engined aeroplanes of a maximum certificated take-off mass of 5 700 kg or less …”. However, it is acknowledged that the aeroplane in this case was a piston-engined aircraft.
The proposal to consider the safety enhancement of lightweight recorders and airborne image recorders to passenger-carrying operations with aircraft with a maximum take-off mass less than5 700 kg will be referred to the FLIRECSWG for further study. The next FLIRECSWG meeting is proposed for June 2022. I trust that the foregoing information meets the intent of the safety recommendation of the Australian Transport Safety Bureau
ATSB welcomes the advice from ICAO that the recommendation for fitment of lightweight and airborne image recorders in aircraft less than 5,700 kg used in passenger carrying operations will be referred to the ICAO Flight Recorder Specific Working Group for further study and consideration. ATSB notes that the next FLIRECSWG meeting is proposed for June 2022 and will monitor progress.
The report of the fourteenth meeting of the Flight Recorder Specific Working Group (FLIRECSWG/14) held in Montréal, Canada from 19 to 21 September 2023 was published on 12 April 2024.
Agenda Item 3.1 LIGHTWEIGHT FLIGHT RECORDERS (REF: JOB CARD FLIRECSWG.009.04)
3.1.1 The member nominated by Australia, presented the FLIRECSWG/14 – WP/3, Fitment of flight recorders for passenger-carrying aircraft under 5, 700kg. The working paper highlighted the recommendation made to ICAO in 2021 as a result of the Australian Transport Safety Bureau (ATSB) investigation of a high-profile fatal accident involving a passenger carrying aircraft of MTOW less than 5,700 kg. It requested that the FLIRECSWG consider expanding the scope of the job card FLIRECSWG.009 to include fitment of flight recorders for not only turbine-engine powered but to all commercial passenger-carrying small aircraft (maximum take-off weight (MTOW) less than 5,700 kg), specifically, a mandate to retrofit all small aircraft involving commercial passenger-carrying operations taking into consideration the recent improved technologies.
3.1.2 The Chairperson briefed that Transport Canada had started to change the regulations in relation to light weight recorders for commercial operated aircraft with maximum take-off weight less than 5,700kg including the business jet operations and flight trainings. The initial requirement was retrofit but the draft regulations had got back a huge number of comments. The biggest push-back came from the business corporate jet. He reminded that the context of light weight recorders should comply with ED-155. The Chairperson highlighted that within Canada the regulations are specific as to voice recordings or on-board video being privileged. They should be installed but not controlled by flight crew. They should start and stop when powers apply.
3.1.3 A concern was raised with regard to mandate of retrofitting taking into account the long retrospective process and its high cost. It was noted that EASA regulations for light weight recorders are limited to turbine-engine powered aircraft plus commercial operations carrying more than nine passengers. A view was expressed that disconnecting propulsion type was a very important point as the new propulsion type such as electrically powered aircraft are coming up, especially for the range of MTOW less than 5, 700kg. Making a connection to passengers at least would be from a safety perspective.
3.1.4 An example of specific niche was provided that the US recommended that the health operation involved aircraft be equipped with flight recorders as FAA recognized that retrofit would have been very difficult to achieve. In the UK, also only a niche of State operations involved aircraft was recommended to have audio and data recording.
3.1.5 It was agreed by the group that going retrofit even with Recommended Practices in Annex 6 would be unlikely to be achieved, in particular if the scope goes beyond the turbine-engine powered. At the same time, the group recognized that the current standard limiting to turbine-engine powered is too restrictive and agreed that a proposal could be developed to recommend having a flight data monitoring (FDM) equipment installed for this category of aircrafts as a starting point. It was noted that the US has recommendations to have FDM equipment installed or FDM programme developed.
3.1.6 In addition, the group discussed the possibility of equipage of AIR system in the lightweight aircraft. A variety of views were expressed on this topic and agreed to keep the dialog open for the next meeting of the FLIRECSWG.
No further action was added to job card FLIRECSWG.009.04 5 Lightweight flight recorders. Current action 9876 Gather statistics related to audio recordings in support of accident and incident investigations of small aircraft engaged in commercial operations with single pilot crew remained with delivery proposed for Q4 2025
The ATSB notes the ICAO working group’s consideration of the recommendation regarding lightweight recorders. It is acknowledged that retrofitting such devices may be challenging. As such, the group determined that, even if it was an ICAO recommended practice, retrofitting was unlikely to be achieved. However, the group indicated that the current standard was limiting as it only included turbine-powered aircraft. They did recognise the possibility of lightweight aircraft being equipped with airborne image recorders, which will be discussed further at their next meeting. Regardless, the ATSB believes there remains an opportunity to consider the fitment of lightweight recorders in existing and new passenger-carrying aircraft with a maximum take-off weight less than 5,700 kg. In particular, this is in consideration of the advancements in technology that have led the way for more cost-effective, self-contained flight data recording systems and airborne image recorders to be accessible to all aircraft.
In July 2020, the Australian Transport Safety Bureau issued a safety advisory notice reminding aircraft maintainers:
The thorough inspection of piston-engine exhaust systems and the timely repair or replacement of deteriorated components is the primary mechanism for preventing carbon monoxide exposure. This, in combination with the assured integrity of the firewall, decreases the possibility of carbon monoxide entering the cabin. The ATSB reminds maintainers of the importance of conducting detailed inspections of exhaust systems and firewalls, with consideration for potential carbon monoxide exposure.
In July 2020, the Australian Transport Safety Bureau issued a safety advisory notice to operators, owners and pilots:
The use of an attention attracting carbon monoxide detector in the cockpit provides pilots with the best opportunity to detect carbon monoxide exposure before it adversely affects their ability to control the aircraft or become incapacitated. The ATSB strongly encourages operators and owners of piston‑engine aircraft to install a carbon monoxide detector with an active warning to alert pilots to the presence of elevated levels of carbon monoxide in the cabin. If not provided, pilots are encouraged to carry a personal carbon monoxide detection and alerting device.
On 3 July 2020, as a result of this investigation, the Civil Aviation Safety Authority released the airworthiness bulletin AWB 02-064 (Issue 1) Preventing Carbon Monoxide Poisoning in Piston Engine Aircraft. This included the following recommendations:
The Civil Aviation Safety Authority recommends that when LAME/AMEs [licensed aircraft maintenance engineer/ aircraft maintenance engineer]. conduct visual inspections of exhaust collectors and heat exchange units, that a thorough inspection is conducted with the view of finding potential CO poisoning points/cracks. Whilst the internal condition and thickness of exhaust components is difficult to determine visually, if the component exhibits signs of thinning, cracking, bulging or any exhaust leakage the section should be removed and replaced with a new or serviceable/repaired item.
An ideal maintenance program would involve system replacement at engine change or at a predetermined interval gained from operating experience. To operate these items to a point of failure is not considered appropriate. Any modification or reduction in length of the tail pipe/exhaust system must be conducted with original equipment manufacturer approval or local Australian CASR [Civil Aviation Safety Regulations] Part 21 approval.
Secondly, approved modifications that include access panels and attachments to firewalls must be re‑sealed following all disturbances to prevent CO entering the cabin. Heating ducts and on/off valves should function correctly, particularly in the off position to allow the pilot to stop the flow of contaminated air entering the cockpit. If an access panel on the engine firewall is opened/removed during maintenance/servicing for gaining access, ensure that the access panel seals/gaskets and hardware is reinstalled correctly to prevent the flow of gases and flammable fluids entering the cockpit and cabin.
Finally, whilst not all aircraft are required to have CO detectors fitted, small electronic personal devices are available at relatively affordable prices, these devices allow for continual monitoring of CO levels with audible and visual warnings when escalated CO levels are detected.
Aircraft certified and hard-wired products are also available that can be installed by approved maintenance repair organisations. Reliance on only the visual CO indicator placard, that changes colour in the presence of CO, is considered suboptimal.
If the aircraft is only fitted with the placard type CO indicator, the operator should ensure the placard is placed in the field of view of the pilot, is regularly checked to ensure that the placard is not time expired and that the indicator is not faded from ultraviolet exposure or contamination.
On 19 October 2020, the Civil Aviation Safety Authority issued version 2 of the above airworthiness bulletin. Specifically, the bulletin strongly recommended that pilots wear personal CO detectors.
Following the accident, prior to recommencing DHC-2 flights on 31 January 2018, Sydney Seaplanes installed a stall warning system to their other DHC-2 aircraft. In addition, GPS tracking devices to provide real‑time positioning information and flight data were installed in all their aircraft. Further, the operator’s pilots completed helicopter underwater escape training.
The operator has amended the DHC-2 system of maintenance, including:
The operator recognised that it was impractical for them to weigh passengers immediately before a flight. However, they now include an additional 5 kg allowance on volunteered passenger weights for when establishing the aircraft’s weight and balance.
