ISO 8267-1:2015

Overview

ISO 8267-1:2015, titled Aircraft - Tow bar attachment fittings interface requirements - Part 1: Main line aircraft, is an international standard developed by the International Organization for Standardization (ISO). This standard specifies the interface requirements for tow bar attachment fittings on the nose gear of conventional tricycle landing gear aircraft used in commercial civil transport. It focuses on main line aircraft with a maximum ramp mass greater than 50,000 kg (110,000 lb), ensuring compatibility under FAR/EASA certification standards (Parts 25).

The primary goal of ISO 8267-1:2015 is to standardize tow bar attachment fittings based on aircraft mass categories, enabling operators and airport handling companies to use a single type of tow bar across different aircraft models within or near the same mass category. This standardization improves operational efficiency and safety during towing operations.

Key Topics

• Applicability: The standard applies exclusively to new main line commercial aircraft models entering service or designed after the publication date, with maximum ramp mass over 50,000 kg, excluding regional aircraft covered by ISO 8267-2.
• Tow Bar Interface Standardization: Classification of aircraft by mass categories to determine tow bar forces, allowing a single tow bar type to suit all aircraft within a category.
• Fitting Location: Tow bar fittings are designed for attachment on the nose gear's front and possibly rear, including options for two-wheel nose landing gear axle fittings if towing loads conform.
• Towing Loads and Forces: The standard specifies allowable towing forces applied to the nose gear fittings and related aircraft structures, including:
  • Forward and aft towing force magnitudes
  • Loads at different swivel angles
  • Formula for towing load based on aircraft mass (e.g., F = 0.15 × M × g)
• Mass Categories: Five standardized mass categories ranging from category I (50,000 kg < M ≤ 100,000 kg) to category V (M > 500,000 kg), guiding tow bar attachment fitting design.
• Fitting Dimensions and Clearances: Tow bar attachment fittings feature a horizontal cylindrical pin with standardized diameter and length specific to each mass category, ensuring proper tow bar engagement.
• Tow Bar Fit Design: Tow bars must uniformly grip 96% to 98% of the pin length and allow positive lock engagement for secure towing.

Applications

ISO 8267-1:2015 serves as a critical standard for:

• Aircraft Manufacturers: Designing nose gear attachment fittings that conform to consistent interface requirements, facilitating compatibility with standard tow bars.
• Airport Ground Handling Operators: Reducing the number of tow bar types needed for various aircraft, lowering logistic complexity and operational costs.
• Maintenance and Safety Personnel: Ensuring towing operations use standardized fittings capable of withstanding specified towing loads, mitigating damage risks.
• Aviation Regulatory Bodies: Supporting certification compliance for tow bar fittings in line with FAR/EASA airworthiness standards.
• Tow Bar Manufacturers: Creating tow bar devices engineered for compatibility across multiple aircraft types within mass categories, optimizing product range and serviceability.

Related Standards

• ISO 8267-2: Aircraft - Tow bar attachment fittings interface requirements - Part 2: Regional aircraft
  Covers aircraft with maximum ramp mass between 10,000 kg (22,000 lb) and 50,000 kg (110,000 lb), complementing Part 1's scope for main line aircraft.

• Federal Aviation Regulations (FAR) Part 25
  Airworthiness standards applicable to transport category airplanes relevant to towing load specifications referenced in ISO 8267-1.

• EASA Certification Specifications (CS-25)
  European standards mirroring FAR Part 25 requirements for airworthiness and towing loads on commercial transport aircraft.

By adhering to ISO 8267-1:2015, the aviation industry ensures safe, efficient, and harmonized ground handling operations, fostering interoperability and minimizing equipment incompatibilities across the global fleet of main line aircraft.