MPD,
Some would argue your comment that hangar and line mx operate at a different pace.
The simple fact is that on the line the system is geared for replacement, etc. If a componant change is required, the relevant manual pages are printed, stands, parts, etc made available so that when the a/c arrives on stand, the job can start as soon as possible, resulting in minimum downtime. There are (usually) enough bodies to do the job and if a duplicate inspection is required, an appropriately licensed engineer is available to carry it out immediately. More often than not the person carrying out the task will certify it too.
In the hangar the task is assigned probably to a mechanic/fitter and he/she "clocks on" to the job. They then have to access the MM to establish what the task involves and what tooling will be required, a/c configuration, etc. They then have to provide access (steps, stands,etc). Now they get the part from stores or the preload shelves (only to find on their return that some toe-rag has moved their steps to do another job
) Now the part is replaced, the old componant is labeled and returned to stores and the paperwork signed on the job card. The fitter can then clock off the card.
Notice that there has been no inspection or function check yet!!
At some later stage, when power is available or when it is safe to operate the replaced componant. An inspector will clock on to the card. They also will have to check in the MM to see what was done and how to function it. They will then carry out the inspection and then (possibly with the help of another engineer for safety reasons) do the function check before signing the relevant documentation and clocking off.
So you can see the process is bound to take longer, although the actual time spent working on the a/c will be pretty well the same.
As for SB's etc. The time quoted on them (for Boeing at least) quite clearly states that it does not factor in job preparation, access, tooling and so on. So again there will be some discrepancy.
Hope this helps.
