I acquired a fan blade a few years back, but have not had any luck finding out who manufactured it or what engine/aircraft it may have come from. The only data I can find on the blade is as follows:

4922T12P01 99207 6018730P02 KGA 65444 GR.IN. 15.620

65444 is hand engraved again in larger size above the data listed, which I assume is the serial number. The blade is about 15" from tip to root. I am curious about the root itself, as I have not seen other blades with a mount like this one. If anyone can help out it would be greatly appreciated.

Blade 1 Blade 2 Blade 3 Blade 4 Blade 5 Blade 6 Blade 7

Images can be seen in full size by clicking on them


3 Answers 3


GE Aviation

Clue 1. Parts designed at the Lynn MA plant have part numbers of the form xxxxTxxPxx, where x is a digit. 4922T12P01 fits that pattern.

The gr.in is another clue. That refers to a weight that would be used in balancing the fan. GE uses units of gr.in. I'm fairly sure that Pratt uses oz.in, snecma uses gr.cm. I'm not sure what RR uses.

But the definitive piece of information is 99207. That is a CAGE code. 99207 is registered to GE Aviation's lynn plant. I looked it up here http://www.govcagecodes.com/

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    $\begingroup$ Good lord... what kind of monster measures torque in gram-inches?! :'( $\endgroup$
    – Dancrumb
    Jan 30, 2018 at 23:00
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    $\begingroup$ Well GE does, but it's not a torque. It's the mass of the part in grams multiplied by the radial distance from the centerline. When the part spins, the centrifugal force is proportional to this quantity. i.e. $F=mr\omega^2$ You want to put heavy blades opposite each other, such that their centrifugal forces balance each other out. $\endgroup$
    – Daniel K
    Jan 30, 2018 at 23:06
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    $\begingroup$ My first thought reading gr.in. is grain-inches. $\endgroup$ Jan 31, 2018 at 9:39
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    $\begingroup$ I was not able to find a publicly available GE manual describing this, but I can assure you it is gram-inches. This site is a pretty good overall of rotor balancing processes (not jet engine specific) engdyn.com/images/uploads/93-balance_this%21_-_peg&tdf.pdf and on page 2 they mention typical units of ounce-inch, gram-millimeter, and gram-inch. $\endgroup$
    – Daniel K
    Jan 31, 2018 at 12:38
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    $\begingroup$ @DanielKiracofe Still, the point stands - I'm not even sure what you would call the chimeric unit of force defined by gr-in/s^2. The "Freedom Dyne"? Have we learned nothing from the Mars Climate Orbiter? $\endgroup$
    – J...
    Jan 31, 2018 at 12:51

That looks very much like a TF-34 fan blade. The TF-34 is used on the A-10 Thunderbolt and S-3B Viking. The root style is known as "pinned" or "clevis". You can see a blade being pinned into the rotor hub in this photo:

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And there is a clear view of the blade root in this photo:

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U.S. Air Force Senior Airman Steven Valencia, 18th Component Maintenance Squadron aerospace propulsion journeyman, cleans and inspects fan blades of a TF-34 engine July 6, 2017, at Kadena Air Base, Japan. The fan blades are used to generate approximately 85 percent of the thrust used by A-10 Thunderbolt II aircraft. (U.S. Air Force photo by Senior Airman John Linzmeier)

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    $\begingroup$ Very good addition to @DanielKiracofe 's finding. $\endgroup$
    – mins
    Feb 1, 2018 at 12:20
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    $\begingroup$ Thank you all for the great information...I have emailed GE as well to see if I can get more detail on manufacture date, but have not heard back as of yet. I am new to this site, but am extremely impressed with the responses and knowledge out there. $\endgroup$ Feb 1, 2018 at 15:39

TF34 Fan Blade - platform reduction

This is a delayed reply. Your fan blade is made of Ti 8-1-1. The gage code is GE however there are only two manufacturers for this fan blade since 1965. The original manufacturer was Utica Drop Forge which became Kelsey Hayes and later became Utica Corporation and currently known as TECT Corporation. The other manufacture was Sermatech Mexico for a very short period of time. Sermatech struggled with holding the geometry of the Ti 8-1-1 material.

Besides the TF34 this almost exact fan blade also goes on the CF34 (Canadair Regional Jet). There are 28 fan blades per engine. Besides the part number the only difference between the military version and the commercial version is the uncut in the platform. This uncut (thinning) of the platform allows for the fan blade to be released on the military version Incase of a fan blade failure. Without this thinning, multiple blades would fail in a domino effect.

The fan blade is precision forged from 2” diameter bar in a 8000 metric ton press (8800 US Tons). After forging it is finished machined.

The manufacturer must retain records for 30 years. The serial number are sequential. GE would need to ask one of the manufacturers for the date of manufacture. The fan blade is not a life limited component and no manufacturing date are applied to the part.



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