MS24665-134 - Textron Aviation OEM Cotter Pin

MS24665-134 – Textron Aviation OEM Cotter Pin

Available now on the Airparts.aero Marketplace.

Overview

The MS24665-134 is a military-standard cotter pin, a fundamental and flight-critical piece of safety hardware used pervasively throughout the Textron Aviation family of aircraft, including Cessna and Beechcraft models. This component is engineered to provide a simple, effective, and visually inspectable method for securing castellated nuts on bolts, studs, and clevis pins, preventing them from loosening under vibration. Manufactured in strict accordance with the MS24665 specification, this cotter pin is fabricated from high-quality, cadmium-plated carbon steel to ensure reliability and corrosion resistance in all operational environments.

What is a Cotter Pin? 
cotter pin or cotter key, is a metal fastener with two tines that are bent during installation, similar to a staple or rivet. Typically made of thick wire with a half-circular cross section, split pins come in multiple sizes and types.

Key Features

• Positive Locking Device: Its sole purpose is to provide a positive mechanical lock for castellated nuts, preventing them from rotating and backing off a bolt. This is a primary safety feature for critical structural and engine hardware.
• High-Quality Carbon Steel: Fabricated from a specified carbon steel alloy that provides the optimal balance of ductility for easy installation and shear strength to resist failure under load.
• Corrosion-Resistant Plating: Plated with a durable cadmium finish per specification QQ-P-416, Type II, Class 3, providing essential protection against corrosion and ensuring the pin's integrity over its service life.
• MS Certified Standard: As a certified Military Standard part specified by Textron Aviation, it guarantees the material, dimensions, and quality control required for use in certified aircraft. It is the superseding part number for the legacy AN380-2-3 cotter pin.
• Extended Prong Design: Features one tine that is slightly longer than the other, a standard design feature that aids in the separation and bending of the tines during proper installation.

Technical Specifications

• Standard: MS24665 (Pin, Cotter, Split)
• Full Part Number: MS24665-134
• Legacy Part Number: AN380-2-3
• Material: Carbon Steel
• Finish: Cadmium Plated, Type II, Class 3
• Nominal Diameter: 1/16 inch (0.063 inches)
• Length: 3/4 inch (0.750 inches), measured from under the head loop.
• Point Type: Extended Prong, Square Cut
• Material:   Steel overall
• Material Document and Classification:   Astm E30 assn std single material response overall
• Surface Treatment:   Cadmium overall and chromate overall
• Surface Treatment Document and Classification:   QQ-P-416, ty 2, cl 3 fed spec single treatment response overall
• Style Designator:   Standard
  

Aircraft Compatibility

The MS24665-134 is a universal hardware item found on nearly every aircraft produced by Textron Aviation. Its use is specified any time a 1/16" x 3/4" cotter pin is required to secure a castellated nut, typically on AN3 through AN5 bolts.

• Common Aircraft Platforms:
  • Cessna: 152, 172 Skyhawk, 182 Skylane, 206 Stationair, 210 Centurion, Caravan, Citation series
  • Beechcraft: Bonanza, Baron, King Air series
• Common Applications:
  • Securing nuts on flight control linkages, pulleys, and bellcranks.
  • Locking wheel axle nuts on main and nose landing gear.
  • Fastening engine mount hardware and structural bolts.

Applications

The MS24665-134 is a critical safety-of-flight component for a multitude of tasks:

• Securing Castellated Nuts: Installed through the drilled hole in a bolt, with the tines spread over a castellated (slotted) nut like the AN310 or AN320, physically preventing rotation.
• Vibration-Proofing: Acts as the final safeguard against fastener loosening in the high-vibration environment of piston and turbine aircraft.
• Pre-Flight Verification: Provides a simple and clear visual confirmation during walk-around inspections that critical fasteners are properly secured.

Why Choose MS24665-134?

The loosening of a critical nut on a flight control bolt or landing gear assembly can have catastrophic consequences. Using a genuine MS24665-134 cotter pin, as specified by Textron Aviation, ensures you are installing a part with a certified material strength and known quality. The use of non-certified hardware store cotter pins is strictly prohibited in aviation as they lack the required material traceability, strength, and corrosion resistance. For any airworthy repair, trust only genuine Mil-Spec hardware.

Order Your MS24665-134 Cotter Pins Now

Stock your shop with the flight-critical, certified hardware essential for safe and airworthy maintenance. Visit Airparts.aero to order your MS24665-134 cotter pins today.

The MS24665-134 cotter pin is a simple yet elegant solution for securing critical fasteners, operating purely on the principle of mechanical interference. After a castellated nut is torqued to its specified value, it is slightly rotated (tightened only) to align one of its slots with the hole in the bolt shank. The cotter pin is then inserted, and the tines are bent. Per standard aviation practice (as detailed in AC 43.13-1B), one tine is bent up and over the end of the bolt, while the other is bent down against the side of the nut. This creates a secure lock that physically prevents the nut from rotating in either direction. The material's ductility is key, as it must bend without fracturing but remain strong enough to resist shearing off under torsional load if the nut attempts to loosen.

Note: Cotter pins are strictly single-use items. A pin that has been installed and bent must never be straightened and reused, as the bending process work-hardens the metal and creates stress risers that can lead to fracture. Always use a new pin for every installation.

This part is used on the following aircraft:

1. Bombardier Challenger 300
2. Bombardier Challenger 601
3. Bombardier Challenger 604
4. Bombardier Challenger 605
5. Bombardier Global Express
6. Bombardier Learjet 40
7. Bombardier Learjet 45
8. Bombardier Learjet 55
9. Bombardier Learjet 60 - all variants
10. Dassault Falcon 2000 all variants
11. Dassault Falcon 7X
12. Dassault Falcon 900 all variants
13. Embraer Legacy 600-650
14. Embraer Phenom 300
15. Piaggio Avanti II
16. Piaggio Avanti P180
17. Pilatus PC-12
18. Piper Aircraft PA-42 Cheyenne
19. Beechcraft King Air 100 - all variants
20. Beechcraft King Air 200 - all variants
21. Beechcraft King Air 300 - all variants
22. Beechcraft King Air 90 - all variants
23. Beechcraft Premier
24. Cessna 500 Citation I-ISP
25. Cessna 510 Citation Mustang
26. Cessna 525 Citation Citationjet
27. Cessna 550 Citation I-II-Bravo
28. Cessna 560 Citation V-Ultra-Encore-Excel-XLS
29. Cessna 650 Citation III-IV-VI-VII
30. Cessna 680 Citation Sovereign
31. Cessna 750 Citation X
32. Hawker 400-400XP
33. Hawker 700
34. Hawker 800XP-850XP
35. Hawker 900XP
36. W/s:aircraft, (AC-130H, MC-130H, EC-130E, HC-130); aircraft, eagle F-15; L.P. compressors; airborne mobile dir air spt ctl (2ID)(02M JUL83)(AN/UYQ-3A); engine, aircraft TF33-P-3/5/9 (C/EC-135, B-52H); gun, 5-IN./54 cal, MK-42 & 45; support equipment, B-1 aircraft; fire pumps; trainer, B-1B aircraft; engine, aircraft TF33-PW-102 (C-135E, EC-135H/K/P); hemtt family (heavy expanded mobility tactical trucks)
    

This may not be a complete list. Check your airframe's IPC for verification before ordering or use. 

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