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Part# 05-01062
MFR Model# UD-3-C
DescriptionPart Number
UD-3-C Fuel Cap with Contoured Adaptor05-01062


The UD-3 flush fuel cap assembly is an unvented cap similar in design to the #5 style cap. The aluminum mounting ring has a 2" dia. opening and an overall dia. of 3-3/4 inch. It may be riveted, bolted or molded to the tank. It is currently used on many popular homebuilts such as the RVís, Lancair, Velocity & White Lightning. Specify flat or contoured adapter.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -

Tech Sheet


welded this to a Midget Mustang header tank and it works great! I highly recommend this.

Stephen T Verified Purchase


November 6, 2023

Great part as per the catalogue.

Ray T
June 19, 2020

Lancair 360 perfect fit and fantastic service again from Spruce

Rob T
March 29, 2020

I used this “cap only” to rebuild a 18 year old cap on my F1 Rocket. The old cap over center feel was getting a bit numb. The new parts fit beautifully and now my caps work like new. A 5 minute job, should have done this sooner.

January 27, 2019

Jim, I needed the Fuel Cap before the July 4 holiday weekend. Called Josh, he handled the sale and it arrived 2 days later! Very pleased with the response from your staff, especially Josh who got the job done!!! I was able to take advantage of the weekend and fly my aircraft!!!! Kudos to Aircraft Spruce, Josh and your staff who made my weekend! Thanks, John

John M
July 10, 2017

Well made and easy to install

Monte H
March 13, 2017

I like this fuel cap. It sits flush, is adjustable (for the tension of the latch) and seals well, Still, I was hesitating between 3 or 4 stars. Spare parts (O-rings) are available but the weakest part is the small pin that keeps the mechanism in place. This part alone is not available. Without it, nothing holds together. I had one failing while I was at a remote airport, Fortunately, i fou d someone over there willing to help and he sacrified a 1/16 drill bit that we broke to make a temporary pin and allow me to get back home. The pin should be offered as a spare part.

Michel T
December 18, 2020


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Which O-ring shall be used with 05-01061? Thanks

You can use either 05-02146 (USHER O-RING 2-325 LARGE) or 05-02147 (USHER O-RING 2-012 SMALL), which can be found in the "Accessories" tab.

Q: What is functional difference of large and small O-rings? Thanks

There is no functional difference. They are used in two different spots of the fuel cap. Both should be replaced annually or as needed. Please see the "Tech Sheet" tab for complete details of where each is used.

Q: What type of allow is the flange of these Usher fuel caps made of?

Per the supplier: It is 6061 alloy.

Q: What is the function of the Contoured Adapter? What shape does it fit?

The function of the contoured adapter is the shape of the ring that the cap will fit into. The contoured ring has a small flange to it compared to the flat adapter which has a flat ring.

Q: Are the Usher flush fuel caps and seals compatible with diesel or Jet fuel?

Yes, these are compatible with diesel and jet fuel.

Q: How much do the 05-01061 & 05-01062 Fuel Caps w/Adaptors weigh? I cannot find a weight on the spec sheet for each assembly.

Each weighs .375 lbs

Q: Can I purchase just the cap without the adapter?

Yes, but this is a special order. Please contact sales department for pricing and lead time details.

Q: What is the OD (outside diameter) of the Contoured Adapter?

P/N# 05-01062 will be 3.80".

Q: What are the outside dimensions of the flange?


Q: What is flat vs countoured?

Contoured is curved to match the curve of a wing.

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