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NTSB report reveals what shattered the window of the deadly Southwest flight

It appears that part of an inboard cowl that shattered the window... read more from the New York Times ( More...

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Ken Hardy 11
Florescent Penetrate Inspection has been used and is still used as the primary MRO inspection process for blades and disks in the LPT section of the engine, only when something like this happens does the OEM or FAA deviate from the FPI process. Penetrant inspection is an AID only to improve a visual inspection process, if not carefully done under controlled application and with clean parts, its adds little to just looking at the part with your eyes. I have spent 50 plus years in Non Destructive Testing of which Penetrate processing is a part of NDT. The bottom line is more frequent inspections using other NDT methods can help this process but they cost time and money something a lot of carriers don't want to spend and the OEM's don't want to admit their engines might need. In this day of mostly 2 engine aircraft, the need to inspect more often is needed.
Very informative post. Wish we had more of them on FA. Thank you Mr. Hardy.
KBartlett 1
Yes, agreed. The FPI is also conducted during initial manufacturing as well as a plethora of other NDIs (ultrasonic, radiographic, etc.) but companies like SWA need to stay on top of periodic inspection also as the engines are used extensively. When I saw some of the articles about the aftermath of this, I noticed they mentioned SWA was conducting on-the-spot ultrasonic inspection. (Or was it Eddy current?) Was confused regarding why they would not just disassemble the fan blades and perform FPI using Level 4 Sensitivity fluid? Figured that would be a more accurate inspection method for microcracks. But I'm not an FPI technician, I just deal with a lot of OEM source inspection on a daily basis and review the initial certs (primarily for defense industry, not commercial, and not on engine components. More structural stuff.) Level 3 is the highest sensitivity requirement I've seen but after poking around online I discovered there's a level 4 and I wondered if that's what they used for engine blade inspections? Also curious if they have to do pre-pen etch on MRO stuff like they do for initial manufactures...? I could see how it would take engines out of service for a little while which can be a pain for airlines wanting to make as much $ as possible but passengers' lives are worth taking the time to do inspection, as someone who flies on the regular, and frequently on SWA at that.
Jerry Klein 2
On another point the story is apparently from the New York Post, not the New York Times.
Good. If it were from the Times, I wouldn't believe it.
Sadus -1
Jesse Carroll -1
sparkie624 3
Interesting that it was inspected 6 years ago and then only by Dye Penetrate Inspection. It appears that engine had been on that wing for a very very long time!
paul gilpin 1
the math given in the article is something else as well.
10K flights in six years is four flights on half the days, five flights a day on the other half.
if that aircraft were a steak, it would be beyond well done.
zach avery 3
age of an airplane isn't relevant. these planes get tore down and inspected after so many hours and when they come out of inspection there like new. some parts like engines are a little bit different, as they may get changed out when there is a problem but those even have a TBO on them.
norman chab 1
Back in the late 50's I was a jet engine mechanic in the National guard. Some inspections required we use a red penetrating dye with a white chalky follow up to test for hidden cracks in turbine blades on our F-86D's. Wonder if it was the same stuff. Sure looks like it.
Ken Hardy 2
It is but the process during engine teardown is now called PE for Post Emulsification the red dye/developer process is only used in the field but is not as sensitive as the PE process
Interview with the Southwest crew tonight 5/11 on ABC's 20/20.
James Carlson 1
That's a pretty good AP article.
Robert Pease 1
Sorry NYPost
Not to be too picky...but it is called Dye Penetrant inspection...not penetrate inspection, although the dye will penetrate any crack present. After cleaning of the suspect area, the appropriate Dye Penetrant is applied for a resident period, then the surface is cleaned of the dye penetrant and a developer is applied to the area of interest. After the appropriate resident period, the area is inspected for signs of cracking that will have been revealed, if present, by the dye that has penetrated the defect or crack as shown by the contrast color, usually white developer, with the usually red dye. Any findings should lead to ultrasonic follow up inspection.
Ken Hardy 3
Sorry but the generic term IS penetrant inspection, florescent inspection is the process of using florescent particles suspended in a oil or water bath. dye penetrant is the process of using red dye that is in a pressurized can and is sprayed on the part allowed to dwell of a period of time then the excess is wiped off and a developer is sprayed on to draw out the red dye both processes do the same thing but I mentioned the process used during MOR overhaul, which is the florescent process which is more sensitive and the ONLY process approved by Pratt, GE or Rolls for blades and disks for MRO inspections and only for the LPT blades HPT blades are cast nickel based alloys with cooling holes, not suitable due to entrapped penetrant that causes excessive background
WhiteKnight77 2
Magnaflux Spotcheck SKL-SP2 and SKL-WP2 comes in 1 gal., 5 gal. and 55 gal. containers as well as aerosol cans. Parts can be dipped in or have it brushed on as well as sprayed on. Zyglo ZL-60D, ZL-27 and ZL-37 come in aerosol cans as well. Personally, I prefer water washable penetrants for most inspections as one just has to spray water and it washes off, no extra steps like Method D.
Ken Hardy 2
Ok, a good comment by someone who knows what Penetrant processing is, glad you did not call it Magnaflux testing which is a Trade Name Company owned by ITW, other companies make the same material. the water wash process is easier but the PE process is the only one approved by the major engine manufactories for teardown and processing of LPT blades and disks. the key to proper penetrant testing is clean parts, correct processing temperatures, dwell times,wash times and following an approved SP and making sure the penetrant material is not contaminated. A little penetrant goes a long way, no need to put a lot on the part as excessive background can mask a defect.
WhiteKnight77 2
I used to send stuff to the NDT shop while with H&MS-36 on Okinawa as a jet engine mechanic, now I do it. I worked a production LPI line several times over the years inspecting industrial gas turbine blades that were either forged or cast. I have held an NAS-410 cert for PT inspections. Those old mercury vapor lamps are junk compared to Labino LED lamps.
Ken Hardy 2
Very good, I am just an old Materials Engineer who has designed and sold NDT systems for the last 40 plus years to just about every OEM in the Airframe and Engine business, I still do consulting work for some of the MRO people. I got my start as a Quality Engineer at Lockheed back in the 60's. your right the LED black lights are much better
KBartlett 1
I recall reading something recently about the mercury vapor lamps not being allowed anymore, at least for the company I work for.
dcmeigs 3
My vote for run-on sentence of the year.
Ken Hardy 3
Sorry you did not get the substance of the comment
My vote for the picky picky comment for this week’s FA. And maybe for the month or year. But we won’t know this now because you or another nit picker might out do your post in pickeyness.
Jesse Carroll 0
WOW...did he hold his breath while typing?So What the process is called! If and that's a big if, I fly commercial again, I want to know the maintenance is at it's best!
That's one reason I never fly Mexican!
KBartlett 1
Ken, your comment actually answered some of the questions I had. :D
Wondered why they would not just perform Fluorescent Penetrant Inspection (FPI) on ALL of the blades... but I guess for the HPT blades they have to worry about the fluid being trapped as you pointed out. So do they just perform ultrasonic on those HPT blades? I had not heard of the red dye inspection before. Must be an MRO thing because I have never seen that requirement during initial manufacturing inspection guessing because it's more for on-the-spot checks vs. up front when the whole thing is already disassembled?
WhiteKnight77 2
Visible dye penetrant inspections are used extensively in the field, especially on stainless steel or other nonmagnetic parts. I have used both MT and PT inspections on welds for structural, piping and other items including boilers for power companies and paper mills. I have even done fluorescent penetrant inspections on a recovery boiler floor (it makes a big mess). It all depends on what you want to find or working with as to the method and type.


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