MENASASI Middle East and North Africa Society of Air Safety Investigators


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CASA: Cabin Safety Bulletin No. 18


Cabin Safety Bulletin 18 Managing passenger comfort devices



Date of publication: 

11 April 2019

A cabin safety bulletin is an advisory document that alerts, educates and makes recommendations about cabin safety matters. Recommendations in this bulletin are not mandatory.

Who does this bulletin apply to?

This document applies to all operators of Australian registered aircraft and should be read in conjunction with section 20.16.3 of the Civil Aviation Orders.


In an effort to improve comfort during flight, passengers increasingly are trying to bring onto the aircraft innovative devices such as knee defenders1, cabin case seat extenders2, leg hammocks3, and baby hammocks4. While the use of some of these devices may not contravene specific safety regulations, they may pose additional safety hazards in the cabin during their operation. Consequently, a number of operators have developed specific criteria as to what comfort devices are acceptable for carriage in-flight. This criterion is not standardised and may differ between operators in relation to comfort devices permitted for carriage and those classified as prohibited.

Legislative requirements

Civil Aviation Order (CAO) 20.16.3 requires that loose articles in the cabin of an aircraft be stowed in order to avoid the possibility of injury to persons or damage to the aircraft through the movement of such articles caused by in-flight turbulence or by unusual accelerations or manoeuvres. The CAO also requires that crew members and each passenger shall occupy a seat of an approved type during take-off and landing; during an instrument approach; when the aircraft is flying at a height less than 1000 feet above the terrain and in turbulent conditions.

Acceptance criteria

Operators yet to develop policy, process and procedures regarding acceptance, use and stowage of these devices should:

  • identify comfort devices passengers attempt to, or successfully bring on board when travelling with small children by way of trend analyses through occurrence report submission
  • identify comfort devices being marketed to passengers travelling with infants/children
  • conduct an evaluation of the safety of the comfort device
  • ascertain the suitability and compatibility of the comfort device with aircraft componentry and approved stowage(s)
  • conduct a risk assessment as to any safety implications for cabin crew members and/or passengers
  • conduct a risk assessment as to the impact on existing procedures, for example, encountering turbulence or impeding egress to emergency exits.

Operators should determine their policy on acceptance and use of these devices by means of a safety risk assessment process, an example of which appears below.

Source: Risk assessment sample from the IATA cabin operations safety best practices guide 4th edition 2018

Hazard (Adverse event) Threat (Potential cause) Consequence (Outcome/Risk)
Overheat or ignition of seat components Device obstructs cooling/ventilation grilles or systems Cabin fire
Ineffective firefighting procedures carried out by cabin crew Device obstructs access to overheating seat components or in-flight entertainment system Uncontained cabin fire
Ineffective firefighting procedures carried out by cabin crew Design of device does not allow removal of lithium battery for firefighting procedures Uncontained cabin fire
Hypoxia following depressurisation incident Device obstructs access to emergency drop-out oxygen masks Incapacitated passenger/crew
Bursting of device following depressurisation incident Device is inflatable, with no emergency release valve Passenger injury
Discomfort to other passengers Device prevents the use of other passengers' seat functions Disputes between passengers and unruly behaviour
Damage to seat components Device imposes abnormal weight/size loads to seat components such as tray table, headrest and armrest Increased maintenance and repair costs
Loose items in cabin during turbulence Device unable to be stowed quickly and safely during turbulence Injury to passengers or crew
Inability to wear seat belt fastened effectively at all times, or during turbulence in-flight Device prevents correct use of seat belt or encourages incorrect positioning around neck or legs Injury to passenger
Exceedance of limitations on carriage of lithium battery in the cabin Device contains lithium batteries which exceed permitted quantities or rating Non-compliance with regulation and increased risk of cabin fire involving lithium battery


Operator considerations in the development of documented procedures and training for crew members, other operational personnel, together with the release of passenger guidelines could include the following.

Cataloguing of comfort devices

  • Definition of comfort devices.
  • Explanatory statement pertaining to comfort devices permissible for carriage and those that are prohibited.
  • Photographic images and schematics of comfort devices that are acceptable for carriage, including positioning of these items across aircraft seating plans.

Aircrew responsibilities

  • Pilot-in-command responsibilities in relation to the determination of comfort devices that are acceptable or unacceptable for carriage where doubt exists.
  • Specific crew member assignments to ensure:
    • appropriate passenger briefings are conducted prior to use detailing phases of flight when the comfort device can or can't be used, for example, item not to be used during illumination of the seat belt sign
    • verification that the comfort device is not located in a position that obstructs the access to, or use of, any required emergency or regular exit, or the use of the aisle between the crew and the passenger compartment, or is located in a position that obscures any passenger's view of the seat belt sign, no smoking sign or placard, or any required exit sign
    • verification that the comfort device is not installed in a position that restricts access to, or use of, any required emergency equipment
    • stowage of the device in an approved cupboard or locker or underseat, during take-off, landing or turbulence
    • verification of appropriate placement restrictions of the comfort device in the cabin, for example, may only be used at a window seat on a single aisle aircraft
    • verification that the comfort device does not impose any load on seats or in the floor structure that exceeds the load limitation for those components
    • verification that the comfort device does not interfere with, and/or potentially damage aircraft componentry/structural integrity, for example, seat recline or attachment points that require use of tray table arms
    • ensure the positioning of an inflation valve is accessible to reduce the deflation time of an item, for example, in the event of an emergency or preparation for landing
    • any safety implications such as the potential for harm or injury to the passenger using the device or adjacent passengers
    • ensuring the comfort device is packaged or covered to avoid possible injury to passengers
    • seat belt use and fitment is possible and effective
    • no interference with a passenger seated adjacent to, or in front of, the comfort device
    • action to be taken by cabin crew in the event a prohibited device is being used in-flight
    • action to be taken by cabin crew in the event an unfamiliar device is being used in-flight.

Decision tool - comfort devices

The below matrix details criteria that could be adapted into a checklist to support cabin crew decision making should a comfort device present which has not been included in operational policy and procedures manuals.

Source: Risk assessment sample from the IATA cabin operations safety best practices guide 4th edition 2018

Question Answer and decision
Is the device within the operator's cabin baggage allowance (weight and dimension)? No - not permitted
Does the device allow the proper use of the seat belt? No - not permitted
If the device is inflatable, does it have a quick release valve or other method to equalise pressure during a cabin depressurisation incident? No - not permitted
Does the device contain lithium-ion batteries with a Watt hour rating of 100 Wh or more?5 Yes - not permitted
Does the device adversely affect the use of another passenger seat, including access to the aisle, seat recline, use of tray table, in-flight entertainment, etc.? Yes - not permitted
Does the device, when attached to any part of the seat or cabin component, impose heavier than normal loads to the seat or cabin component? Yes - not permitted
Does use of the device obstruct cooling/ventilation systems, or does it obstruct decompression vents in floor or side wall area to the point of preventing air flow? Yes - not permitted
Could the device become loose and cause injury to others during turbulence? Yes - not permitted
Does use of the device prevent any person from rapid access to emergency oxygen masks during a depressurisation event? Yes - not permitted
Does use of the device prevent cabin crew access to electrical systems or components during an overheat, smoke or fire event? Yes - not permitted


  • Procedural information developed is mapped to existing manual provisioning to ensure compatibility.
  • Hazard occurrence reporting criteria to include reference to comfort devices attempted to be brought on board, used in-flight or removal from stowage that may cause injury to passengers or crew members.
  • Safety awareness training for aircrew and ground operational personnel as it relates to comfort devices.
  • Instruction to crew members relating to the stowage and removal of a comfort device from an approved stowage in-flight or after landing to prevent injury to themselves or other passengers.

Information dissemination

  • Communication methods relating to comfort devices permitted or prohibited for crew members, other operational personnel and passengers.
  • Monitoring of new product releases and release of requisite communication of comfort devices that are permitted or prohibited for awareness of crew members, other operational personnel and passengers.
  • Aimed at passengers relating to the removal of a comfort device from an approved stowage in-flight or after landing to prevent injury to themselves or other passengers.

Additional resources

1 Knee defenders prevent the seat in front of the passenger from reclining

2 Cabin case seat extenders provide support for an infant or child during flight allowing them to sleep

3 Leg hammocks attach to the seat in front to provide a foot/leg rest

Baby hammocks provide additional comfort for lap-held infants

5 Passengers may carry a device containing a lithium-ion battery greater than 100 Wh and no greater than 160 Wh with the approval of the operator