Aircraft Hold Open Rods

MarathonNorco is the industry and technology leader for Nacelle Hold Open Rods. We are on every major single and twin aisle platform in the world.  Telescoping and fixed-length struts are produced in a wide variety of sizes, shapes, lengths and special features, making them well suited for many industrial, commercial, marine and aviation applications.  MarathonNorco produces struts for proof loads as heavy as 11,000 pounds and for ambient temperature conditions approaching 1,000 degrees F. Every strut features a patented locking mechanism and design flexibility with multiple end-fitting compatibility, rod end bearings, universal joints, clevis pins and more


  1. Automatic locking with Norco’s patented Couplex™ lock up; no loose parts.
  2. Easy release by pulling or sliding the release collar to disengage the Couplex™ pin from the receiver.
  3. Optimum weight/strength rations for tension/compression loads. High-temperature units readily available.
  4. Enhanced safety through a patented secondary lock or release collar where multiple telescoping struts operate under heavy loading.
  5. Design flexibility due to multiple end-fitting compatibility, including rod end bearings, universal joints, clevis pins and more.
  6. Automatic locking when extended; high strength assured through the use of patented locking mechanisms.

Whether it’s to support an engine cowling, protect the rotors of an in-transit helicopter, or for any custom application where dependable positive support is required, MarathonNorco has the experience and expertise you require.


Marathon Norco features an entire family of Fixed Length, Telescopic, Folding Hold Open Rods (HORs) featuring Locking Collar (Pull Then Lift Technology) and multiple interface methods (Rod End Bearing, Couplex, and Universal Joint) for a wide variety of nacelle applications including traditional Receiver/Spool and Passive/Zero Wear Receiver.

  • Several MNAI Hold Open Rods incorporate our patented damping technology to control the rate of extension and retraction based on a specified load range.


Our current line of HORs

  • Single Stage HOR – One lock collar actuated to extend or retract the Hold Open Rod.  Can be permanently attached or stowed on the cowl.
  • Two Stage HOR – Two locking mechanism’s and three tubes.  Can be permanently attached or stowed on the cowl
  • Fixed Length HOR – Typically used along with a Couplex where the rod can be stowed away and then raised up and clipped into a receiver when the door is opened.
  • Folding Hold Open Rods – Typical for access door panels


Current Types of Locking Options

  • Extend then Pull (no unlock under load) – Cowl Door must be raised, relieving the load on the Hold Open Rod, before the lock collar can be actuated
  • Pull then Lift – Designed to hold ultimate load after unlocked and to automatically unlock after load is removed with no collar operation.
  • Turn then Pull – Ensures no accidental unlock of release collar.  Good for areas with higher than normal snag or accidental grab potential.
  • Damping Capability (Hydraulic & Mechanical)