Accident G-CICF
Accident involving an Ikarus C42 FB80 Bravo (G-CICF), Headcorn Aerodrome.
AAIB Report: Ikarus C42 FB80 Bravo, G-CICF, on 8 December 2022
Safety Recommendation: 2024-006
It is recommended that the Civil Aviation Authority amends the design and installation requirements for lithium-ion main batteries that are located in the cabin areas of Non-Part 21 aircraft, to minimise the hazard to aircraft occupants following a thermal runaway.
We have been continuing to work with the Light Aircraft Association (LAA) and British Microlight Aircraft Association (BMAA) to review and, where necessary, amend their existing standard modifications for fitment of lithium main batteries in place of standard lead-acid batteries to ensure the installations comply with the relevant design and installation requirements.
Further research has since taken place on thermal runaway, fire risk, least risk location and crashworthiness to ascertain the perceived event probability. Based on recent correspondence with the LAA and BMAA as of June 2026, advanced drafts of Technical Directives, Standard Minor Modification procedures, and associated Technical Leaflets are currently undergoing review by relevant subject matter experts. Subject to completion of this review, these documents will be issued by the LAA/BMAA imminently for consultation with A8-1/A8-21 organisations and relevant members.
Following the consultation period, final promulgation of all necessary documentation including service bulletins is currently planned to take place by the end of Q3 2026.
At the time of writing the expected compliance timescale for any directive issued by the LAA/BMAA is likely to be during 2027, but active discussions remain ongoing at this time.
It is worth re-iterating that considering the above proposals are focusing on evolving modification procedures, there is no current intention to amend initial airworthiness requirements for lithium-ion batteries.
It is still the intention towards the conclusion of this process to remind organisations holding an A8-1/A8-21 approval of their obligation to disseminate safety information (such as service bulletins) issued by the aircraft manufacturer, ensuring that critical safety updates reach operators in a timely manner.
The CAA will provide a further update on the actions taken to address this Safety Recommendation by 31st October 2026.
Partially Adequate - Open
31/10/2026
AAIB Recommendation transmittal
Date
16/02/2024
Status
Open
CAA Initial Update
Date
24/04/2024
The CAA accepts this Safety Recommendation.
The CAA will assess and, where appropriate, amend the design and installation requirements for lithium-ion main batteries located in cabin areas of general aviation (GA) aircraft with a view to minimising the hazard they pose to aircraft occupants. Although the safety recommendation scope is limited to non-Part 21 aircraft, the CAA has since become aware of some Part 21 GA aircraft that have a similar battery configuration; the assessment will therefore include Part 21 and non-Part 21 GA aircraft.
The CAA will provide an update on the actions taken to address this safety recommendation by October 31st 2024.
Status
Open
AAIB Classification
Date
30/05/2024
Status
Adequate - Open
CAA Update
Date
31/10/2024
The CAA has completed an initial review of the Part 21 and non-Part 21 design and installation requirements for lithium-ion main batteries located in cabin areas of general aviation (GA) aircraft.
The initial airworthiness requirements contained in BCAR Section S, CS-VLA, CS-LSA, CS 22, and CS-23 were considered as part of this review. We found that each design code includes requirements to protect occupants from hazardous quantities of explosive or toxic gas emitted by batteries, both in normal operation and following probable malfunctions. Part 21 aircraft fitted with lithium battery installations are held to a higher safety standard and are required to comply with the additional requirements in SC-ELA.2015-01 as well as the requirements in the relevant Certification Specification. We therefore consider Part 21 aircraft to be adequately protected from the risk of a lithium battery fire at this time. However, we recognise that non-Part 21 aircraft fitted with a lithium main battery are at increased risk in this regard and we endeavour to address this.
We will work with the Light Aircraft Association (LAA) and British Microlight Aircraft Association (BMAA) to review and, where necessary, amend their existing standard modifications for fitment of lithium main batteries in place of standard lead-acid batteries to ensure the installations comply with the relevant design and installation requirements.
We will also be reminding organisations holding an A8-1 approval of their responsibility to promulgate safety information (e.g. service bulletins) issued by the aircraft manufacturer to ensure that critical safety information is provided to operators in a timely manner.
The CAA will provide an update on the actions taken to address this safety recommendation by April 30th 2025.
AAIB Classification
Date
24/12/2024
Status
Partially Adequate - Open
CAA Update
Date
28/04/2025
We are continuing to work with the Light Aircraft Association (LAA) and British Microlight Aircraft Association (BMAA) to review and, where necessary, amend their existing standard modifications for fitment of lithium main batteries in place of standard lead-acid batteries to ensure the installations comply with the relevant design and installation requirements.
Several meetings have taken place between the BMAA, LAA and CAA since the last update. A gap analysis between UN 38.3 and DO-311A has been undertaken concluding that there are no significant differences between the two technical specifications. Work continues on the design and installation review aspects and the considerations to amend current LAA/BMAA modification procedures.
Once this work is completed, we will then be reminding organisations holding an A8 1 approval of their responsibility to promulgate safety information (e.g. service bulletins) issued by the aircraft manufacturer to ensure that critical safety information is provided to operators in a timely manner.
The CAA will provide a further update on the actions taken to address this Safety Recommendation by 30th September 2025.
AAIB Classification
Date
23/05/2025
Status
Partially Adequate - Open
CAA Update
Date
30/09/2025
We have been continuing to work with the Light Aircraft Association (LAA) and British Microlight Aircraft Association (BMAA) to review and, where necessary, amend their existing standard modifications for fitment of lithium main batteries in place of standard lead-acid batteries to ensure the installations comply with the relevant design and installation requirements.
The most recent trilateral meeting between the CAA/LAA/BMAA was held on the 18th September 2025.
From this recent meeting, it has been agreed that respective procedures surrounding standard modifications for LAA/BMAA aircraft require updating to ensure only batteries that meet the relevant Technical Standards Order (such as those meeting DO-311A standards) are to be located aft of the firewall. These procedural updates are anticipated during the first quarter of 2026 and will be customised as required to the respective LAA/BMAA fleets.
It has also been considered that where necessary, alternative means of compliance giving an equivalent level of safety would be considered via the normal modification processes for each respective organisation.
Additionally, mandatory technical directives and mandatory permit directives are being considered as a potential course of action. This would mandate the removal of any LiFePO4 batteries aft of the firewall unless of a type meeting the relevant Technical Standards Order (or otherwise approved by the CAA/LAA/BMAA). A sufficient timeframe for compliance is currently being considered by the CAA/LAA/BMAA.
Considering the above proposals focusing on evolving modification procedures, there is no current intention to amend initial airworthiness requirements for lithium ion batteries. There are however plans to remind organisations holding an A8-1 approval of their responsibility to promulgate safety information (e.g. service bulletins) issued by the aircraft manufacturer to ensure that critical safety information is provided to operators in a timely manner.
The CAA will provide a further update on the actions taken to address this Safety Recommendation by 30th March 2026.
AAIB Classification
Date
27/11/2025
Status
Partially Adequate - Open
CAA Update
Date
31/03/2026
We have been continuing to work with the Light Aircraft Association (LAA) and British Microlight Aircraft Association (BMAA) to review and, where necessary, amend their existing standard modifications for fitment of lithium main batteries in place of standard lead-acid batteries to ensure the installations comply with the relevant design and installation requirements.
From our recent correspondences with LAA/BMAA, work continues to focus on revising and updating Standard Minor Modification procedures and associated technical leaflets. These are now anticipated to be completed by the end of April 2026.
Additionally, further research on thermal runaway, fire risk, least risk location and crashworthiness is being performed and correlated with the perceived event probability. Once the research has been concluded, revisions to modification procedures will be finalised and Mandatory Directives drafted and consulted on with a view to publishing by the end of May 2026.
It is worth re-iterating that considering the above proposals are focusing on evolving modification procedures, there is no current intention to amend initial airworthiness requirements for lithium-ion batteries.
Plans are also still in place to remind organisations holding an A8-1 approval of their responsibility to promulgate safety information (e.g. service bulletins) issued by the aircraft manufacturer to ensure that critical safety information is provided to operators in a timely manner.
The CAA will provide a further update on the actions taken to address this Safety Recommendation by 30th June 2026.
AAIB Classification
Date
27/04/2026
Status
Partially Adequate - Open
CAA Update
Date
30/06/2026
We have been continuing to work with the Light Aircraft Association (LAA) and British Microlight Aircraft Association (BMAA) to review and, where necessary, amend their existing standard modifications for fitment of lithium main batteries in place of standard lead-acid batteries to ensure the installations comply with the relevant design and installation requirements.
Further research has since taken place on thermal runaway, fire risk, least risk location and crashworthiness to ascertain the perceived event probability. Based on recent correspondence with the LAA and BMAA as of June 2026, advanced drafts of Technical Directives, Standard Minor Modification procedures, and associated Technical Leaflets are currently undergoing review by relevant subject matter experts. Subject to completion of this review, these documents will be issued by the LAA/BMAA imminently for consultation with A8-1/A8-21 organisations and relevant members.
Following the consultation period, final promulgation of all necessary documentation including service bulletins is currently planned to take place by the end of Q3 2026.
At the time of writing the expected compliance timescale for any directive issued by the LAA/BMAA is likely to be during 2027, but active discussions remain ongoing at this time.
It is worth re-iterating that considering the above proposals are focusing on evolving modification procedures, there is no current intention to amend initial airworthiness requirements for lithium-ion batteries.
It is still the intention towards the conclusion of this process to remind organisations holding an A8-1/A8-21 approval of their obligation to disseminate safety information (such as service bulletins) issued by the aircraft manufacturer, ensuring that critical safety updates reach operators in a timely manner.
The CAA will provide a further update on the actions taken to address this Safety Recommendation by 31st October 2026.
AAIB Classification
Date
20/07/2026
Status
Partially Adequate - Open