The next time you complain about the cost of parts or aviation generally.

[gaunty]

We take too much for granted, when we press the start button, the technology and smarts behind that simple action are almost unbelievable. We've come a long way since Orville and Wilbur.:ooh:

CF34 Break-up Prompts Emergency AD
The FAA issued an emergency AD on Friday to all owners and operators of GE CF34-3A1, -3B and -3B1 turbofans after NTSB investigators found an electrical arc-out defect in the fan disk of the engine that broke apart on a Mesa Airlines Bombardier CRJ200 during a revenue flight on January 25. The AD requires a one-time visual and tactile inspection of parts of fan disks on 31 specific engines, identified by serial number, within 20 engine flight hours of its receipt. The engines in question power 50- and 44-seat Bombardier CRJs and Challenger 601/604 business jets. After examining pieces of the engine found within a square mile of rural Colorado, the NTSB determined that an electro-chemical etch marking applied during engine assembly to align the fan disk and shaft caused the defect.

[Capn Bloggs]

electro-chemical etch marking = Texta?:{ Permanent or whiteboard??

[gaunty]

Bloggs old chap

From an ad extolling the virtues;

Electro-Chemical Etching is a Marking method that etches a perfectly high contrast, non removable marks into any material that conducts electricity. It does not heat up the material and does not weaken or alter the microstructure of the material. as they say "tell it to the marines"

[Scurvy.D.Dog]

Ooopps ....... :E :ooh: :E

[Pinky the pilot]

as they say "tell it to the marines"
Gaunty me old; I wonder how long it will be before it's a case of....
''Tell it to the Judge!"":eek: :ugh:

[gaunty]

Pinky mate

and thats why parts and aviation are /is so expensive.:mad:

[YesTAM]

I've seen very large and highly expensive Boeing bits ruined by a chance spark as they were taken out of an anodizing tank...makes you want to cry.

[VH-Cheer Up]

Shouldn't the power be switched off before you put anything into or take it out of an etch/plating tank?

How do you get a chance spark with the power off?

[Allan L]

Static Electricity is a pretty amazing thing!!! And it can be created in lots of ways, like something holding it's charge when the power is off - a capacitor is a device that does this very well (as some will know from painful experience!), but lots of things act like a capacitor to some extent.:hmm:

[Deaf]

"It does not heat up the material and does not weaken or alter the microstructure of the material"

Perfectly correct.

However think of the way corrosion works on 2024 as compared to pure aluminium. In this case with some materials there will be some selective removal which has the effect of starting a crack (note this is on the microscopic or sub optical microscopic scale). This is how etching for metallographic examination works where some of the microstuctural elements are removed on the etched surface.

An etched specimen will have the same strength as an unetched specimen if given a tensile test. Fatigue and creep may be quite different.

[YesTAM]

Absolutely correct VH Cheer-up. Power should have been switched off. However this is the least of Australias "quality control issues".

Think inspectors at Lynne dumping Australian made F404 turbine blades on a table , the rejecting them for dings.

Think unauthorised gauges used to reject Australian manufactured T700 casings and suchlike and you get the full flavor of American "protectionism".