FlightAware is registering BOE5 as a Boeing 737-800 - um, last I checked, that isn't a 787 Dreamliner....
I think they use the last couple digits of the line number as the flight number, so any time a 737 comes out XXnn005 it will fly as BOE5.
I was a flight test engineer at Boeing starting in Feb 79, was Test Director on the #4 767 and several others (including "Spirit of Delta" which resides at the DL museum in ATL) from Dec 81 thru Sep 82
they actually use what is called the Tab (Tabulation) Number ... each model has a unique first letter (as I recall, major production variants get unique second letters), and customer orders are assigned blocks of numbers ... here's what I remember
727-200 is Q (the 727-100 was E followed by four numbers)
737-200 is P
747 is R (the #1 jet at the Museum of Flight is RA001)
757-200 is N
767-200 is V
777-200 is W
787 is Z
> UA was the launch customer for the 767-200 with an order for 19 jets; they were Tab Numbers VA002-VA020 (again, the #1 jet was VA001)
> DL was the second customer and had Tab Numbers VA301-VA315 for their -200s
> other early 767-200 customers were AA and TW; their blocks started at VA501 and VA801 (not sure which was which)
when VA004 was on a test flight we would use "Boeing 004" as our call sign ... if the #4 757 (NA004) was going to be in the air before we landed, they would typically use "Boeing 574" or something similar ... on occasion there were two production jets with the same block numbers but different tabs (for example, 737s with Tab Numbers PH478 and PN478 -- these may or may not be real; one might be a -700 and the other a -900); one would file with the Tab Number and the other would likely use its production line number ... note that the Tabulation Blocks are irrespective of production line number, since customers typically take delivery of a block of jets over several years; I seem to recall that they are assigned in increments of 10 (and "in bulk" for many orders, particularly if the customer includes options), so not all Tab Numbers in a Tab Block may actually be produced
the #1 jets typically used the model number as their call sign (e.g.
, "Boeing 747" and "Boeing 767")
here are some examples of downstream Tab Blocks:
> NW was the launch customer for the P&W JT9D-7Q engine on the 747-200; their first jet was RD251 and the call sign throughout the certification flight test program was "Boeing 251"
> the four 767-200s converted to AWACS for Japan were VF181-VF184
> the first in the block of 20 British Airways 737-200s delivered around 1980 was PK731; it required a rather extensive flight test program for CAA certification and was known as "Boeing 731" for most of that period
> the 747SPs were tabbed RG and RH; the two that were delivered to TWA were RG191 and RG192
> I think the first 767-300 was VN001