How can I tell what fuel filler caps (gas caps, fuel filler cap, original style cap) I have? Or what part number to replace them with?
Search strings: fuel filler cap data, HE623, HE627, Aero Shaw, 431-9
Fuel Filler Cap Data, Models 19/23/24
Most of the cap manufacturers have placed identifying information on the caps themselves. These numbers may be stamped on, stamped in, or molded in.
Earliest Model 23: Original fuel cap with flat neoprene seals (not o-rings). Airframe serial numbers M1 through M53, except M25 and M40; M54; M57 through M61; M64 through M71; M73; M74; M76; M80; M82; and M85. The flat seals are PN 25C85-114, and may still be available from Falcon Crest Aviation in Atlanta. RAPID no longer carries them, as Beech “required” all those original caps to be replaced with the later o-ringed version.
H&E Aircraft HE-627 caps were installed on the above aircraft per SB-2, in kit #23-1-1, dated December 1962. These replacement caps incorporated o-ring seals rather than flat neoprene seals. They were installed in production on subsequent (and the above excepted) airframes.
Service Letter SL-63-9 authorized placement of a locating stripe on the caps and neck, to help ensure that the protruding locking pins on the HE-627 caps did not strike and damage the fuel level tab in the tank when they were extended during locking.
Mandatory Service Instruction SI-0801-287 Revision 1 required the replacement of the HE-627 filler caps, using the 169-380024-601 cap and adapter assembly (cap and filler neck; $333 in 2005, but currently priced at $3,300 from RAPID, and none are available). This SI applied to airframes M1 through M554; essentially all the production through the end of 1963. This involved only Model 23 planes, as none of the other Aero Center models were in production in 1963.
The primary parts provided in the -601 kit (excludes hardware) were:
169-380024-3 adapter (filler neck)
169-380024-1 fuel filler cap (Shaw Aero numbers 431-9, 431-9R, or 531-046)
169-110000-341 adapter gasket
169-110000-349 fuel level indicator tab
At one time H&E Aircraft caps (HE-623-4) were introduced as Beech PN 169-380024-5. These have since been again superseded by the original 169-380024-1 caps (made by Shaw Aero; currently available for $691 from RAPID). The 169-380024-5 part number no longer appears as a valid number in the RAPID parts system.
In May 1989, Beech issued Mandatory Service Bulletin SB-2045. This SB was very wide-ranging, essentially applying to the entire piston-engined fleet (both singles and twins). The kit that applied to all models and airframe serial numbers of the Aero Center line was number 36-5012-1 S (note the blank in front of the S; no longer available from RAPID). Aircraft that have this kit installed will have the Shaw Aero filler cap PN 531-046. The Beech number for this cap is 36-380095-1 (currently available for $202 from RAPID). In my experience relatively few owners elected to install this kit; I have encountered very few Aero Center planes with them installed. They were never installed in production, as the kit was introduced six years after airframe production was halted. One minor drawback is that the adapter insert results in the cap sitting about one-sixteenth of an inch above the filler neck adapter itself; a very slight increase in drag.