FITTING AY (P/N 491-4) - New Surplus

The 491-4 is a 37° flare hose fitting assembly conforming to MS24587 aerospace standards. It comprises an AN818-style nut, threaded nipple, and hose socket for terminating Aeroquip 303 hose to 37° flare tube connections. Commonly used in aircraft fuel, hydraulic, and pneumatic systems where reliable fluid-line sealing is critical.

Installation requires the proper assembly mandrel and torque specification per the hose manufacturer and aircraft maintenance manual to ensure leak-free performance.

What is the FITTING AY (P/N 491-4)?

The 491-4 is a 37° flare hose fitting assembly conforming to MS24587 aerospace standards. It comprises an AN818-style nut, threaded nipple, and hose socket for terminating Aeroquip 303 hose to 37° flare tube connections.

Is the 491-4 a PMA or OEM part?

The FITTING AY may be available as an OEM (Original Equipment Manufacturer) or PMA (Parts Manufacturer Approval) part depending on condition and source. Both carry FAA certification for airworthiness. Currently available in: New Surplus. Contact us for sourcing details.

Does the 491-4 include installation hardware?

Installation hardware requirements vary by application. Check your aircraft's Structural Repair Manual (SRM) or Illustrated Parts Catalog (IPC) for the complete installation kit requirements for the FITTING AY. We stock related hardware and can help identify companion parts.

Can the 491-4 be shipped internationally?

Yes, we ship airframe components worldwide. International orders typically arrive within 3-14 business days depending on destination. Export documentation and customs forms are included. Contact us for international shipping quotes on the 491-4.