In aviation get in
discussions with customers all the time where the OEM will give the estimated for hours for a Service Bulletin, Mod, or Task and it does not include any of the preparation, access or required inspection time.
Something like riveting an additional support brackets (just some angle) on the equipment rack, they give 8 hours for the mod.
- They don't mention that you have to remove all the units in equipment rack to get access (CB Panel, Stall Warning Computer, Fuel Quantity and Indication Computer, Flap/Stab Electronic Control Unit, VHF 1, VHF 3, Radio Interface Unit, Transponder 1, Junction Box 1 and 3, Traffic Collision Avoidance System Unit, Position Sensor Electronic Unit... off the top of my head.)
- I should note that to get into the equipment rack in the first place you have to remove the equipment rack covers.
- The bottom screws on the lower cover sit beneath the carpet (or vinyl) flooring in the entry.
- That flooring is one piece through the galley to the cabin so you've got to remove the metal thresholds.
- The threshold has no screws on top (which is aesthetically pleasing), it's secured via an L bracket that runs lengthwise so you've got to un-tuck the carpet on the cabin side and get those screws out.
- All the above done gets you to the inside of the equipment rack, for the outside you to remove the wooden entryway bulkhead.
- To remove that bulkhead you have to remove the vestibule/entryway headliner.
- To remove that you have to remove the main entry way door trim.
Some of these things require two people (like dropping the headliner) but figure you're 20-ish man hours into the job before the 8 hour mod
.
You complete the mod, and put everything back together, let's call it 12-14 hours for reassembly.
- Then you get to perform all the ops checks for everything you took it.
- One of those checks is swinging the landing gear.
- Put the aircraft on jacks, electrical power (lucky you this aircraft has electric hydraulic pumps).
- But realistically figure 8 man hours for ops checks.
We account for all this in pre-planning so our quote to the customer for the mod is probably in the neighborhood of 50 hours.
- To be fair the Mod
does state 8 hours for the direct task, which is shooting rivets.
- But as you can imagine, customers do not want to hear that noise
.