ISO 45:1990

Overview

ISO 45:1990 - Aircraft - Pressure refuelling connections - defines the mechanical interface for aircraft pressure refuelling connectors. The standard specifies the basic dimensions of the connector and the required access clearance around it so that hose units, bayonet lugs and refuelling equipment are interchangeable and operable in typical ground- and flight-line conditions.

Keywords: ISO 45:1990, aircraft pressure refuelling connections, refuelling connectors, dimensions, access clearance, aviation fuel handling.

Key topics and technical requirements

• Basic dimensions: The standard sets the connector geometry (referenced as figure 1 and table 1 in the document) to ensure consistent fit between aircraft inlets and refuelling hose assemblies. Example nominal values included in the standard are diameter A = 57.2 mm (2.25 in).
• Bayonet lug arrangement: Connectors use three bayonet lugs and corresponding slots, spaced so each lug centreline is 60° ± 2° from adjacent slot centrelines to ensure reliable mechanical engagement.
• Valve face and travel: The valve face must be flat within the specified diameter and no part of the valve may extend below this face. The valve is spring-loaded; the document specifies valve travel and a maximum load - e.g., 36.52 mm (1.438 in) travel with loading not to exceed 222 N (50 lbf) at that travel.
• Mounting orientation notes: When fitted on an overhead horizontal surface (for example under a wing), one bayonet lug must be centrally located towards the normal approach of the operator. For other mountings, one lug should be at the lowest point of the connection.
• Access clearance and side-by-side installation: Clearance around the connector is defined (see figure 2). The standard also provides minimum centre spacing for side-by-side installations - permitting 355.6 mm (14 in) centres where required - and assumes a hose of 76.2 mm (3 in) outside diameter with a minimum bend radius of 304.8 mm (12 in).

Applications and users

ISO 45:1990 is used to ensure mechanical compatibility, safety and ease of operation for pressure refuelling across the aviation industry:

• Aircraft manufacturers (OEMs) designing refuelling inlets
• Ground-support and refuelling equipment manufacturers (nozzles, couplings, hoses)
• Airport fuel service operators and maintenance engineers
• Regulators and certification authorities concerned with fuel handling and ground operations

Related standards

• Standards and specifications from ISO technical committee ISO/TC 20 (Aircraft and space vehicles) and national aviation fuel-handling regulations complement ISO 45:1990. Use this standard together with applicable national/regulatory fuel-safety requirements and airworthiness guidance for full compliance.

This standard promotes interoperability, operator safety and predictable installation layout for pressure refuelling systems in aviation.