Boeing Test Registrations

[Duchess_Driver]

I thought these were “unique” until the aircraft was delivered then re-used but...

trawling through street view on google maps around Renton there are several instances of N1786B with different “fleet” numbers and different customers livery or parts thereof. The images all come from May 2019 and don’t appear to be doctored at all but I am no image specialist.






Can anyone explain the system to me.... ( yep, I’m bored!)

[esscee]

They could be using the Boeing Line number as Reg, line number being the number given to each aircraft as it is manufactured on the Boeing production line and then is also specifically used for identification purposes in the manuals.

[Donkey497]

I guess that you can paint whatever you like on the side of the hull, whenever you like, just so long as there's only one combination of registration and MSN in the air or with live transponder on the ground at any given period. Possibly just a case of Boeing, with better visibility of the relative completion states, production and delivery schedules for these MSN's than us mere mortals just finishing off the livery enough for each to take it's sequence of test & pre-delivery flights in turn under the same recyclable registration.

[DaveReidUK]

Originally Posted by esscee

They could be using the Boeing Line number as Reg, line number being the number given to each aircraft as it is manufactured on the Boeing production line and then is also specifically used for identification purposes in the manuals.

Boeing don't use Line Numbers as registrations (l/n 1786 was an NG built in 2005) and, as with all manufacturers, it's the serial number (MSN) that is used to identify individual aircraft in technical publications, ADs, etc.

[G-ARZG]

FAA allows re-use of N nrs, example FAA's own N1 has adorned a number of cabs over time. So no surprise for Boeing test regs (as with Airbus F-Wxxx and D-Axxx)

[EGTE]

I visited Renton in August 2019 and yes, there were several 737Max with the same test registrations. N1786B was noted on 19 different airframes parked around the airfield and outside the factory. The registration marks N1787B, N1798B and N1796B were also noted on single airframes.

[Duchess_Driver]

You can see the line number above the hold, and this is different to the actual MSN for the aircraft which (I imagine) run sequentially across all product lines (73, 74, 77 and 78)

Well, if it was painted 19 times then....

Possibly just a case of Boeing, with better visibility of the relative completion states, production and delivery schedules for these MSN's than us mere mortals just finishing off the livery enough for each to take it's sequence of test & pre-delivery...

doesn’t quite fit.

[Dave Therhino]

It's listed in the FAA registry as a manufacturer's temporary registration number held by Boeing. Some of the 737s are painted at the Renton factory. Some are flown a few miles away to a paint hangar at Boeing field. I suspect they use this number and others for the short flight to the paint hangar or any other flying before it is painted. Once it's painted it would have the customer's registration number on it, but still could be flown for acceptance or test flights with a different temporary N number issued to Boeing.