Attention:
Transport Category Aeroplane Type Certificate Holders and Canadian Aviation Regulations (CAR) Subpart 705 Airline Operators
| File Classification No.: | Z 5000-35 |
|---|---|
| RDIMS No.: | 20259604 |
| Document No.: | CASA 2024-07 |
| Issue No.: | 01 |
| Effective Date: | 2024-07-10 |
Purpose:
The purpose of this Civil Aviation Safety Alert (CASA) is to:
- (a) raise awareness about the potential risk associated with the transportation in the flight deck of portable electronic devices (PEDs) powered by lithium batteries that are not part of the aeroplane type design, lithium battery power banks or spare lithium batteries;
- (b) provide recommendations to mitigate that risk; and
- (c) provide guidance on how to implement those recommendations.
Background:
In recent years, Transport Canada has made significant efforts to address the threat associated with thermal runaway of rechargeable and non-rechargeable lithium batteries certified as part of the type design of the aeroplane.
Nonetheless, crew members and passengers bring on-board a significant number of lithium batteries not included in the type design of the aeroplane.
For this reason it is common to find in the flight deck of transport category aeroplanes PEDs powered by lithium batteries, such as electronic flight bags or devices carried by the flight crew for personal convenience (mobile phones, tablets, laptop computers, e-cigarettes, etc.). In addition to PEDs, power banks or spare batteries are also common on the flight deck.
Lithium batteries, including the ones that power PEDs, may experience thermal runaway. A thermal runaway may result in the release of heat, smoke, flames and in some cases explosion. The Federal Aviation Administration report DOT/FAA/TC-16/37 shows how a lithium battery cell in thermal runaway may experience a rapid and uncontrolled temperature rise, with peaks that may exceed 760 °C.
The increasing number of PEDs containing lithium batteries carried by the flight crew on commercial transport aeroplanes results in a higher risk of in-flight lithium battery fire on the flight deck. When compared with similar event in the passenger cabin, the consequence of an in-flight lithium battery fire on the flight deck is significantly more serious.
Typical locations for PEDs on the flight deck may be stowage compartments or mounting brackets. The flight crew may connect PED lithium batteries to a power supply unit available on the flight deck, or even to a power bank.
On certain aeroplanes, the flight deck stowage compartments may be located in close proximity to critical systems, such as flight controls and oxygen lines.
In the event of a battery thermal runaway, the flight deck would be potentially affected by generation of heat, smoke and flames, as well as by explosions.
Transport Canada acknowledges that in the last 20 years the progressive worldwide increased availability of PEDs has led to a corresponding increase of the transport of PEDs in the flight deck. However, designs of aeroplanes previously certified might not have considered the risk of PEDs that are not part of the type design into their safety assessment. Therefore, this CASA raises awareness and provides recommendations to mitigate the risk of battery fires on the flight deck of these aeroplanes.
For applications for type design and certain changes to the type design, Transport Canada will address this risk during their approval process.
Recommended Action:
Transport Canada recommends the following mitigating actions.
- (a) Transport Category Aeroplane Type Certificate Holders or CAR Subpart 705 Airline Operators:
- (1) Develop emergency procedures to manage lithium battery fires on the flight deck considering the different threats (i.e. heat, smoke, fire and explosion) associated with a potential lithium battery thermal runaway event. See Appendix A for guidance.
- (b) Transport Category Aeroplane Type Certificate Holders:
- (1) Develop service bulletins for each aeroplane model to:
- (i) modify flight deck stowage compartments/mounting brackets to carry/hold PEDs, power banks and spare batteries when an evaluation based on a fire hazard assessment determines that they are unsuitable, and the emergency procedure does not require the removal of the PED or the battery experiencing a thermal runaway from the flight deck. See Appendix C for guidance; and
- (ii) identify each flight deck stowage compartments/mounting bracket with regards to its suitability, or not, to carry/hold PEDs, power banks and spare batteries based on the fire hazard assessment results. See Appendix C for guidance.
- (1) Develop service bulletins for each aeroplane model to:
- (c) CAR 705 Airline Operators:
- (1) Develop and implement adequate training for the flight crew members and flight attendants on the performance of the emergency procedures in Recommended Action (a)(1).
- (2) Provide suitable on-board emergency equipment to effectively follow the emergency procedures, either located in the flight deck or in close proximity so that it can be timely retrieved by the flight crew members or flight attendants. See Appendix B for guidance.
Reference Documents:
- (a) Federal Aviation Administration report DOT/FAA/TC-16/37, Summary of FAA Studies Related to the Hazards Produced by Lithium Cells in Thermal Runaway in Aircraft Cargo Compartments, dated June 2016.
- (b) European Union Aviation Safety Agency Special Condition SC-G25.1585-01 Issue 2, dated April 26, 2022.
- (c) Society of Automotive Engineers (SAE) ARP 4761A, Guidelines for Conducting the Safety Assessment Process on Civil Aircraft, Systems, and Equipment.
Appendix A
Emergency Procedures Guidance
As per SAE ARP4761A, Appendix L, fires originating from batteries are a particular risk. When an emergency procedure is part of the mitigating measures to render the risk acceptable, the type certificate holder or airline operator should include the procedure in the Aeroplane Flight Manual or Flight Crew Operating Manual-Quick Reference Handbook. The emergency procedure specified in the section Recommended Action should consider the following guidance:
- (a) The PEDs, power banks and spare batteries may be in stowage compartments, mounting brackets or personal belongings of the flight crew — the procedure should account for all possibilities.
- (b) A lithium battery fire on the flight deck could be potentially catastrophic and therefore the procedure should involve either the removal of the PED, power bank or spare battery from the flight deck or placing it in a safe stowage that is readily available on the flight deck.
- (c) The procedure should include the use of cold liquids to cool the item containing the battery or the battery.
- (d) The Transport Category Aeroplane Type Certificate Holder should evaluate the likelihood of the active participation of the flight attendants on the emergency procedure.
- (e) The procedure should make clear whether the aeroplane should land as soon as possible.
Appendix B
Emergency Equipment Guidance
The emergency procedures specified in the section Recommended Action should foresee the use of special approved emergency equipment (for example fire gloves) necessary to move an overheated PED, power bank or spare batteries to a defined location on the flight deck or in the passenger cabin. The designated stowage location of such equipment should be within easy reach of each flight crew member and should be marked accordingly.
Appendix C
Service Bulletin Development
When developing the service bulletin, the type certificate holder should perform a hazard assessment supported by test evidence to determine the suitability of each stowage compartment and mounting bracket in the flight deck to stow or hold PEDs, power banks and spare batteries. The hazard assessment should cover all the consequences of a thermal runaway event, including:
- (a) build-up of smoke and toxic gases released from the battery, taking into account the performance of the aeroplane flight deck smoke evacuation system when conducting the smoke evacuation procedure;
- (b) the need to remove the item containing the battery or the battery from the flight deck, if applicable;
- (c) the consequences of the use of cold liquids to cool the item containing the battery or the battery as part of the emergency procedure;
- (d) the impact of the heat generated by the battery on the physical integrity of stowage compartments or mounting brackets;
- (e) the potential damage caused by corrosive leakage from the battery; and
- (f) the proximity of critical systems (such as oxygen systems, wire bundles, other batteries, etc.) potentially affected by direct flame impingement or heat transfer should be taken into account.
The hazard assessment should consider a representative lithium battery fire in terms of heat, smoke and toxic gases generation. In absence of any empiric information, it is known that in a thermal runaway a representative battery could reach temperatures as high as 760 °C and the event could have a duration of at least 2 minutes. The Type Certificate Holder should submit to Transport Canada for review and acceptance the test setup and procedure of any test being conducted to support the hazard assessment.
Contact Office:
For more information concerning this issue, or to comment, contact Standards Branch Documentation Services, at email: AARTDocServices-ServicesdocAART@tc.gc.ca
Original signed by
Linda Melynk
Director
Standards Branch
The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.