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JAL B772 at Okinawa - Dec 4th 2020

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JAL B772 at Okinawa - Dec 4th 2020

Old 10th Dec 2020, 22:47
  #21 (permalink)  
 
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Originally Posted by Dave Therhino View Post
The initial NTSB press releases for 3472 incorrectly used the term "uncontained" (as does Wikipedia), but if you read the subsequent NTSB accident report for 1380 in the section on previous incidents they state the fan blade in the 3472 event did not breach the containment ring or the debris shield that was part of the inlet inner wall structure, and they do not use the term "uncontained" in that later summary of the 3472 event.
Not only is it referred to in the later SWA1380 report, but it's also stated explicitly in the SWA3472 Final Report that Simon kindly supplied a link to (above):

"The fan case had no through-hole penetrations and showed no evidence of an uncontainment [sic]". (P16)
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Old 10th Dec 2020, 22:51
  #22 (permalink)  
 
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Please be carefull in comparing engine and aircraft certification material. They serve different purposes and might be inconsistent if taken out of their context.

At engine level, uncontained failure is typically associated with casing performation. The engine certification cannot assess installation effects. On this basis, SWA is not an uncontained engine failure, from the strict engine point of view.

At aircraft level, not so. EASA AMC 20-128A and FAA AC 20-128A, which are identical, provide an engine failure model, based upon historical data, which includes fan blade fragments with a spread angle reaching up to 15 of the nominal rotation plan (9.e). Typically, this addresses fan blades released forward of the fan containment system, exactly as in the case of SWA1380. The SWA1380 event is an uncontained failure engine failure. .

And bearing in mind that from a safety point of view, what really matters is the aircraft and not the engine, it is fair to conclude we can consider the event as uncontained engine failure.
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Old 11th Dec 2020, 02:26
  #23 (permalink)  
 
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DaveReidUK

Yes, and I participated in drafting the AC in both the engine and airframe regs. I wrote the strawman summary words and the lawyers and wordsmithers altered them to their satisfaction. I take no other ownership other than the intent to clarify and improve safety of flight. I still feel they guide the investigator's findings in creating specific areas under continued airworthiness against which to write recommendations..

I can tell you that the doers don't have a problem in applying corrective action against the design intent. Thus I see no benefit in continuing this wordsmith debate
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Old 11th Dec 2020, 05:52
  #24 (permalink)  
 
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Having read through all the posts so far, it seems that each reference to 'fragments' is confusingly ambiguous, at times meaning engine fragments, at others fan/rotor blade fragments, but it is often open to interpretation, i.e. not made clear which is meant.
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Old 11th Dec 2020, 07:58
  #25 (permalink)  
 
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Not really. The 13 references to "fragments" in the thread so far (prior to your post) all make it clear that they refer to blade/rotor fragments, i.e. the rotating components of an engine. I can't see any ambiguity.

Originally Posted by lomapaseo View Post
Thus I see no benefit in continuing this wordsmith debate
Yes, I think we've got to the stage (npi) where we're stretching semantics beyond its elastic limit - one is reminded of Humpty Dumpty's famous saying.

Getting back on topic to the subject of the thread, it now seems clear that there's no evidence so far to support the proposition that any part of the two damaged fan blades on the JAL 777 exited by penetrating the fan case.
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Old 11th Dec 2020, 15:59
  #26 (permalink)  
 
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Austrian Simon

Please show me and everyone else where in the JSTB report stating they have opened an investigation, they say the words you posted in brackets.

Also, look up the definition of penetration.

I'd suggest you don't use an automatic translator, copy and paste especially with a language like Japanese as well.
Do you feel free to post your reply in Japanese if you wish.
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Old 11th Dec 2020, 17:24
  #27 (permalink)  
 
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The original is at: Investigation Notification JA8978

If you doubt the translation of that note's type of occurrence, here is the English translation by the JTSB themselves out of older already completed accident reports, with exactly the same Japanese categorization ("発動機の破損(破片が当該発動機のケースを貫通した場合に限る。)に準ずる事態"): "Damage of engine (limited to such a case where fragments penetrated the casing of subject engine)"

BTW, the JTSB uses the word penetration as the part going through the hole, as several already released English final reports make clear.

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Old 11th Dec 2020, 19:37
  #28 (permalink)  
 
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Full text of the JTSB Accident/Incident Categorization under which this event will be investigated:



(per Ordinance for Enforcement of the Civil Aeronautics Act, Article 166-4)

Clearly this categorization encompasses both contained and uncontained failures.

While it's certainly true that recent JTSB engine failure investigations covered by this categorization relate to uncontained failures, that has no bearing on the JAL event - which clearly wasn't, as the investigation report will show in due course.

Last edited by DaveReidUK; 11th Dec 2020 at 20:38.
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Old 11th Dec 2020, 21:35
  #29 (permalink)  
 
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Only problem being, that in the actual classification of the occurrence there is no mention of the major damage inside the engine but ONLY the mention of fragments penetrated the casing of the subject engine. You quoted the generic regulativ that mentions all possible types under Article 166-4:

Article 166-4 of the Ordinance for Enforcement of the Civil Aeronautics Act (The case prescribed in the Ordinances of the Ministry of Land, Infrastructure. Transport and Tourism under Article 76-2 of the Civil Aeronautics Act)

1. Take-off from a closed runway or a runway being used by other aircraft or aborted take-off
2. Landing on a closed runway or a runway being used by other aircraft or attempt of landing
3. Overrun, undershoot and deviation from a runway (limited to when an aircraft is disabled to perform taxiing)
4. Case where emergency evacuation was conducted with the use for emergency evacuation slide
5. Case where aircraft crew executed an emergency operation during navigation in order to avoid crash into water or contact on the ground
6. Damage of engine (limited to such a case where fragments penetrated the casing of subject engine or a major damage occurred inside the engine)
7. Continued halt or loss of power or thrust (except when the cngine(s) arc stopped with an attempt of assuming the engine(s) of a motor glider) of engines (in the case of multiple engines, 2 or more engines) in flight
8. Case where any of aircraft propeller, rotary wing, landing gear, rudder, elevator, aileron or flap is damaged and thus flight of the subject aircraft could be continued
9. Multiple malfunctions in one or more systems equipped on aircraft impeding the safe flight of aircraft
10. Occurrence of fire or smoke inside an aircraft and occurrence of fire within an engine fire-prevention area
11. Abnormal decompression inside an aircraft
12. Shortage of fuel requiring urgent measures
13. Case where aircraft operation is impeded by an encounter with air disturbance or other abnormal weather conditions, failure in aircraft equipment, or a flight at a speed exceeding the airspeed limit, limited payload factor limit operating altitude limit
14. Case where aircraft crew became unable to perform services normally due to injury or disease
15. Case where parts dropped from aircraft collided with one or more persons
16. Case equivalent to those listed in the preceding items

As I said, the JTSB themselves translate the exact same Japanese text (in the classification of this occurrence of JA8978) as: "Damage of engine (limited to such a case where fragments penetrated the casing of subject engine)" and do not cite the other option of major engine damage.

Apples and Bananas ...

Again, the Japanese text you quoted: "六 発動機の破損(破片が当該発動機のケースを貫通し、又は発動機の内部において大規模な破損が生じた場合に限る。) translates to: "Damage to the engine (limited to cases where the fragment penetrates the case of the engine or a large-scale damage occurs inside the engine)
The text of the occurrence in comparison: "発動機の破損(破片が当該発動機のケースを貫通した場合に限る。)に準ずる事態" which translates to: " Situations equivalent to damage to the engine (when debris penetrates the case of the engine)" and the JTSB translates this exact phrase: "Damage of engine (limited to such a case where fragments penetrated the casing of subject engine)"

Last edited by Austrian Simon; 11th Dec 2020 at 21:50.
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Old 12th Dec 2020, 18:52
  #30 (permalink)  
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