ISO 8267-2:2023

Overview

ISO 8267-2:2023 specifies interface requirements for tow bar attachment fittings on the nose landing gear of regional commercial transport aircraft (designs entering service after publication). The standard applies to regional aircraft with a maximum ramp mass up to 50 000 kg (110 000 lb) and aims to standardize tow bar interfaces so a single tow bar type can serve multiple aircraft models.

Key benefits: reduced towing equipment variety, improved ground handling efficiency, consistent safety margins, and defined retrofit paths for some in-service aircraft.

Key Topics

• Scope and applicability: Applies to new regional aircraft models within the specified maximum ramp mass range. It excludes commuter-category aeroplanes and main line aircraft covered by ISO 8267-1.

• Fitting location: Requires a forward, easily accessible attachment on the nose gear for push/pull towing. Rear fittings are not required; an axle fitting may be used for two-wheel nose gears if towing loads are within limits.

• Towing loads and compliance: Towing load capability must meet applicable airworthiness regulations (e.g., 14 CFR Part 25, EASA-CS 25, paragraph 25.509). The standard provides the towing-load basis and ensures fittings are designed to withstand specified limit loads.

• Fitting configuration and dimensions: The standard specifies a horizontal cylindrical pin as the nominal fitting configuration. Nominal pin dimensions by category (from the standard) include:

  • Category I: diameter 19.05 mm (0.75 in), length 38.10 mm (1.50 in)
  • Category II: diameter 25.40 mm (1.00 in), length 63.50 mm (2.50 in) The tow bar device must grip the pin uniformly over approximately 93–95% of the pin length and be adjustable to provide positive engagement when locked.

• Mass categories and design guidance: Aircraft families that bridge mass categories are advised to adopt a single fitting interface, typically the higher-category dimensions, to avoid changes during development and to accommodate potential mass growth.

Applications

• Aircraft OEMs: design nose-gear fittings to conform to the standardized interface and towing-load requirements.
• Airport ground handlers and operators: use standardized tow bars across regional fleets to reduce inventory and complexity.
• Maintenance and retrofit teams: apply the document’s described retrofit option where appropriate to render certain in-service fittings compatible with standardized tow bar heads. The standard includes an example retrofit using a machined spacer (approx. 0.23 kg) for converting existing fittings.

Related Standards

• ISO 8267-1 - Tow bar attachment fittings interface requirements - Part 1: Main line aircraft
• Regulatory references: 14 CFR Part 25 and EASA-CS Part 25 (paragraph 25.509 on towing loads)

ISO 8267-2:2023 is focused on practical, safety-driven standardization of tow bar interfaces for regional aircraft to streamline ground operations while ensuring compliance with airworthiness towing-load requirements.