Engine changes

[Grandad Flyer]

Can anyone tell me the requirements, as far as paperwork and signing off go, for an engine change on a commercial jet, say a B737. Is it that one engineer/ group of engineers will put the new engine off, sign it off and then it is checked and a duplicate signing completed? What tests are then performed to ensure correct installation? Appreciate any info from current engineers.

[Pen-off Pete]

Usually there would be a pre printed set of step by step instructions with a box to sign for each step and a seperate sheet for each trade certifier to certify for the work package itself. Typical function checks for a 200 737 would be a check of all the valves, generator output, csd disconnect and adjustment of the LVDT for power lever angle for the auto-throttle. The Heavies would also do trim runs for throttle stagger and power assurance checks. A 300 series would be similar with possibly a gain check of the PMC. Hope this helps

[spannersatcx]

Grandad flyer, would also add that normally (depends where you are) 1 engineer would normally be in charge of team and would be responsible for the overall task, then a 2nd certifying engineer would carry out duplicates as detailed in the check sheets, normally torque loading of eng mount bolts and connection of thrust cables (if any). Type of eng run required would depend on eng being installed i.e pre bence tested would need less than an untested engine, in addition to the tests as detailed by pen-off pete.
Hope that helps Brgds spannersatcx