ENG709

7th July 2022

Charging oxygen systems on the ramp

Initial Report

I have noted that [Operator] at [Location] still charge crew & portable O2 bottles. This procedure was removed from the AMM many years ago and the [Aircraft] doesn’t have an external charging point. The AMM procedure has been for many years to replace the Crew/Portable O2 bottles when they are below minimum levels. The Oxygen bottle is on a towable trolley that sits out in the open next to where the passengers queue prior to boarding. I haven’t actually seen them recharging bottles but the rig has been in use for years. I haven’t seen a designated toolbox for the same reason stated above, there isn’t any fire extinguisher in the area and there isn’t any kind of cage to place a bottle in during re-charge. I am not aware that they have a workshop/clean room at [Location]. My biggest concern is for the guys working for [Operator] as I suspect they feel they cannot complain.

CAA Comment

CHIRP Comment

This report has great merit because it was a case of ‘something is not quite right here’. The reporter carried out a subconscious risk assessment and took appropriate action in contacting CHIRP and we approached the operator’s NAA with the reporter’s consent. It transpired that the practice was allowable under a ‘Local Agreement’ with the NAA, which had been in place for approximately fifteen years whereby the operator’s Part 145 ‘Component Rating C15 Oxygen’ could cover all their outstations. The NAA were satisfied that the Maintenance Organisation Exposition/Procedures, Dedicated Approved Tooling, Explosion Protection and Fire Extinguishing were all in place. The paperwork for the recording of work was by an internal document, which is also permissible. Local agreements do have a place in making regulations work until they can get up to speed with industry changes and needs. The question therefore must be, does a local agreement show that the regulation (and/or the AMC or GM) is inadequate in the first place, and for how long should they be allowed to be in place? When maintenance personnel use a work-around based on a local agreement, is the organisation assuming it will be addressed properly at a later date?

Ordinarily a C15 Approval would require a facility designated for the purpose, which would of course have to be free of dust and oil. As you would expect, this local agreement also relies on the training, authorisation and competence of the individuals carrying out the work. The one requirement missing from the checklist in this case however is the facility! The lack of a facility demands a bit of common-sense of these individuals. We don’t normally get to use much common-sense in aircraft maintenance anymore because aircraft, procedures, approved maintenance data and Human Factors training all try to pre-empt any likely errors. One must assume that in this case the individuals involved have the common-sense not to attempt to carry out this practice in any sort of bad weather. How many potential Human Factors issues have just crossed your mind that might make it seem like a really good idea to ignore the weather just this one time to get the flight away?

A further question raised by this report is whether an engineer should query the practices of others in other organisations? We as engineers would hope they do every time something looks amiss; any engineer should challenge what they perceive as a safety issue or a breach of regulations. It is great to think that one day you might be the engineer that saves lives with a ‘good spot’ that everyone else has overlooked but, unfortunately, (Human Factors yet again) it is often a balance between our safety conscience and looking foolish. Would you call the Tower to inform them an aircraft taxying out is covered in ice, or would you possibly hope it might be taxying to a remote location for de-icing? A Just Culture protects against being thought of as foolish – after all, there is no such thing as a silly question.

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