What it is
What AASSEP-04 governs
AASSEP-04 is the NATO Allied Technical Publication that fixes the coupling between an aircraft tyre and the equipment used to inflate it, so a valve built by one nation's manufacturer connects to another nation's ground servicing equipment. Its own stated aim is direct: "the aim of this standard is to standardize tyre valve couplings to facilitate cross-servicing of aircraft." Nations record their agreement to use it in STANAG 3209, which is how AASSEP-04 acquires force among nations that have ratified it: "the agreement of nations to use this publication is recorded in STANAG 3209."
The publication is short and almost entirely a hardware interface specification. Chapter 1 lists three non-NATO documents as related reading, all concerned with tyre valve threads, dimensions and core chambers: ISO 4570, ISO 7295 and ISO 20562. Chapter 2, Requirements, is where the specification itself sits, split into configuration and additional requirements, each pointing to one of five annexes that carry the detail.
Configuration and additional requirements
The configuration clause fixes the coupling end of the standard tyre valve: "the standard tyre valve, for use on all aircraft tyres, shall be provided at the coupling end with an external thread" and an internal core chamber, built "in accordance with the normal commercial design of the tyre valve manufacturers" and detailed further in Annex A. The valve also has to take one of the short valve cores or the long valve core shown in Annex B, with the core pin positioned as Annex A's own figure shows.
The additional requirements clause calls up three more annexes: "a valve sealing cap, as shown in Annex C, shall be used with all aircraft tyre valves," tyre valve threads built to Annex D, and access clearance dimensions built to Annex E.
What the five annexes cover
Annex A, Valve Stem, gives the coupling's core chamber configuration and notes that the valve mouth's counterbore is optional, with the surface built smooth enough to seal against the valve cap's gasket. Annex B, Valve Cores, covers three variants - a short core with an outside spring, a short core with an inside spring, and a long core - and requires every aircraft valve core to carry a brass or copper-coloured pin and plunger cup, with the swivel able to rotate independently of the barrel. Annex C, Valve Cap, requires a sealing gasket on the cap fitted to every valve. Annex D, Thread Details, sets out the coupling thread's own basic plan and dimensions. Annex E, Access Clearance, requires that a valve fitted with its cap stays within the width of the wheel, and keeps the space around it clear enough for a ground crew wearing arctic gloves to reach it for inflation.
None of the annexes' own dimensions, thread forms or tolerances are reproduced here: they are the reason a manufacturer buys the document, and this page describes what each chapter covers rather than the figures inside it.
What it does not cover
AASSEP-04 sets no design process, no acceptance test, and no certification, audit or inspection scheme for checking that a manufactured valve actually meets these dimensions. It fixes the interface and stops there; conformance is established the way any hardware specification is, through a manufacturer's own design and inspection records.
AASSEP-04 is published by NATO and listed free of charge in the NATO Standardization Document Database. NATO's documents are not sold by ComplyTrain and we host no copies of them.