Approved Procedures For Cleaning Ng Blades?

[silvrado17]

Would the use of a double pointed scribe to scrape, chip, &/or fragment the caked/baked on debris (carbon &/or crystallized sand) coating on the Ng blades of a turbine engine be considered an "approved procedure"?

 

I witnessed this in my organization, it didn't seem right & was told to 'go away' when I questioned it (another flag).

 

The practice of using a scribe seems as though it could cause a stress point which could ultimately lead to a fatigue fracture & catastrophic engine failure.

 

Any engine gurus out there that can shed any insight on this?

[splitpin]

Would the use of a double pointed scribe to scrape, chip, &/or fragment the caked/baked on debris (carbon &/or crystallized sand) coating on the Ng blades of a turbine engine be considered an "approved procedure"?

 

I witnessed this in my organization, it didn't seem right & was told to 'go away' when I questioned it (another flag).

 

The practice of using a scribe seems as though it could cause a stress point which could ultimately lead to a fatigue fracture & catastrophic engine failure.

 

Any engine gurus out there that can shed any insight on this?

Don't have to be a 'engine guru' for this one. Common sense and good maintenance practices will work just fine

There are chemical removal procedures for that sort of thing. Bead blasting is also sometimes used. Blades are very suseptible to the smallest microscopic scratches that will lead to failure down the road. I would take it up with your QA folks. If that fails, move on before you get trapped into thinking bad work practice is the norm.

[212wrench]

Would the use of a double pointed scribe to scrape, chip, &/or fragment the caked/baked on debris (carbon &/or crystallized sand) coating on the Ng blades of a turbine engine be considered an "approved procedure"?

 

I witnessed this in my organization, it didn't seem right & was told to 'go away' when I questioned it (another flag).

 

The practice of using a scribe seems as though it could cause a stress point which could ultimately lead to a fatigue fracture & catastrophic engine failure.

 

Any engine gurus out there that can shed any insight on this?

 

[silvrado17]

haha, nice photo...very applicable.

 

I know, the whole situation is difficult for me. Not really anyone listening to my concerns here...needed to bounce it off some non-biased maintenance folks just to make sure I am not off base that what I saw was wrong.

 

Thought that just maybe, I was unaware of that technique as an approved procedure?

 

It mostly seemed like this was that "point of origin" sought by crash investigators.

 

moving on....

 

thanks.

[KnuckleDragger]

Depends on engine, material, debris. If you are scraping debris and not blade then no problem. There are procedures in some books for dressing out nicks on blades. Bottom line is just take the time to read all applicable documentation including SB, ASB, SI, and SL etc. Being told to go away does not constitute an error on their part but maybe a repeat attitude of judgement without education on yours. Sometimes engineers are busy.