MERGED: Air Asia Turnback Perth 25 Jun 17
We're not talking about a fatigue regime here, we're talking about potential damage caused by the aircraft trying to shake itself to bits.
We're not talking about a fatigue regime here, we're talking about potential damage caused by the aircraft trying to shake itself to bits
For some engine failures, severe vibration may be experienced after the engine has been shut down, to the point where instruments are difficult to read. This vibration is caused by the unbalanced fan, windmilling at an engine speed close to an airframe’s natural resonance frequency, which amplifies the vibration. Changing airspeed and/or altitude will change the fan windmill speed and an airplane speed may be found where there will be much less vibration. There is no risk of airplane structural failure due to vibratory engine loads during this windmilling action.
I think you would have a hard time justifying that decision if it happened at the furthest distance out from KGI and ADL. If you have nominated Forrest as an alternate, then fly past it for another 1.5 hours plus on one engine, when the checklist says land at the nearest suitable I would suggest you may come in for some scrutiny.
Obviously if there wasn't much in it then ADL or KGI is the better option but if the engine fails in the worst possible position then it will be tough to justify pressing on. The other consideration is if you press on then something else goes wrong that leads to an accident you are going to get smashed in an inquiry or court case.
Obviously if there wasn't much in it then ADL or KGI is the better option but if the engine fails in the worst possible position then it will be tough to justify pressing on. The other consideration is if you press on then something else goes wrong that leads to an accident you are going to get smashed in an inquiry or court case.
I think you would come in for an even greater amount of scrutiny if you attempted to land at Forrest at typical weights that you could expect to arrive at. Utilising YFRT as a non-EDTO adequate is fraught with problems. Have you ever done a LDR calculation at typical weights you may arrive at? The answer will be enlightening and surprising. If you lose an engine over the bight you won’t be able to land at YFRT, even using un-factored distances. So you will be much better off flying beyond the non-EDTO distance OEI and landing at an aerodrome that has sufficient runway – or insisting on an EDTO plan and check before departing.
Join Date: Aug 1999
Location: UK
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
This is a AirAsia. The crew are trained in all normal and abnormal techniques. However, Allah rules the day. Trust in God, Allah and we will survive. When the situation gets tough, the tough pull out the koran not the QRH.
Its a cultural thing, and cannot be trained out of them .
Korean Air had the same problem of cultural loss of face in the 1990's , causing several preventable tragedies. SIA suffered a similar fate with SQ6 . I worked in SQ, their cultural indoctrination was prevalent in the cockpit. No amount of inhouse training can remove it, not now, not ever.
Its a cultural thing, and cannot be trained out of them .
Korean Air had the same problem of cultural loss of face in the 1990's , causing several preventable tragedies. SIA suffered a similar fate with SQ6 . I worked in SQ, their cultural indoctrination was prevalent in the cockpit. No amount of inhouse training can remove it, not now, not ever.
Hi Nev,
I think you would come in for an even greater amount of scrutiny if you attempted to land at Forrest at typical weights that you could expect to arrive at. Utilising YFRT as a non-EDTO adequate is fraught with problems. Have you ever done a LDR calculation at typical weights you may arrive at? The answer will be enlightening and surprising. If you lose an engine over the bight you won’t be able to land at YFRT, even using un-factored distances. So you will be much better off flying beyond the non-EDTO distance OEI and landing at an aerodrome that has sufficient runway – or insisting on an EDTO plan and check before departing.
I think you would come in for an even greater amount of scrutiny if you attempted to land at Forrest at typical weights that you could expect to arrive at. Utilising YFRT as a non-EDTO adequate is fraught with problems. Have you ever done a LDR calculation at typical weights you may arrive at? The answer will be enlightening and surprising. If you lose an engine over the bight you won’t be able to land at YFRT, even using un-factored distances. So you will be much better off flying beyond the non-EDTO distance OEI and landing at an aerodrome that has sufficient runway – or insisting on an EDTO plan and check before departing.
Not too many would want to land there on one engine methinks.
Aplogies to 172 owners
Landing was sweet.
* This included a funny conversation between a Malaysian carrier and a controller asking if an ILS to runway 27 would be okay in Melbourne. The pilot replied that he required an ILS to runway 34. The controller told him he'd be waiting a while. "How long?" came the reply. "Some years!….34 doesn't have an ILS but a VOR approach is available"
"Runway 27 will be okay then."
Join Date: Jun 2017
Location: Perth, Western Australia
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
My apologies, I'd misinterpreted the way this issue is typically reported in our local media and I now understand the difference - thank you.
I've read every single word in this entire thread, as Air Asia and their Perth operations are particularly relevant for me. I'm also a technically minded aircraft enthusiast with a very good understanding of most aspects of this incident (and I held a student licence at one time).
Quite clearly I'm not the only non-pilot here and I have to say, I find some statements made by people who do appear to be pilots quite disturbing. The lack of understanding by some of how 'ETOPS' relates (or otherwise) to this incident is a good example.
I am interested in both sides of the debate on the choice to fly all the way back to Perth and especially interested in the comments from those with engineering backgrounds (mainly non-pilotes too I assume?) - their input is especially relevant.
I've read every single word in this entire thread, as Air Asia and their Perth operations are particularly relevant for me. I'm also a technically minded aircraft enthusiast with a very good understanding of most aspects of this incident (and I held a student licence at one time).
Quite clearly I'm not the only non-pilot here and I have to say, I find some statements made by people who do appear to be pilots quite disturbing. The lack of understanding by some of how 'ETOPS' relates (or otherwise) to this incident is a good example.
I am interested in both sides of the debate on the choice to fly all the way back to Perth and especially interested in the comments from those with engineering backgrounds (mainly non-pilotes too I assume?) - their input is especially relevant.
Have you ever done a LDR calculation at typical weights you may arrive at? The answer will be enlightening and surprising. If you lose an engine over the bight you won’t be able to land at YFRT, even using un-factored distances.
My assumption in my previous post was that the aircraft is capable of doing it and that the weather was OK.
Just to keep the discussion regarding the turn-back decision alive, consider this prior event.
Yes, I know that changes were mandated and hopefully carried out following that incident, but until that incident occurred the T700 was already, at that time, supposed to be resilient to a fan blade failure. Clearly it was not.
This most recent failure on D7237 seems to show somewhat more of the blade missing than the 130 mm cited in the CX case. Hence greater imbalance and presumably, greater amplitude of vibration.
I am somewhat dubious about the Boeing claim that such vibration is "unlikely to lead to further damage" when in this CX case it clearly did just that.
Duration of CX event - failure to on-the-ground - 28 minutes.
And, yes; they must have flown past Batam.
That more serious consequences did not eventuate is no guarantee that they could not have occurred at any time during that 1:45 turn-back..
Refer : https://www.mot.gov.sg/news/20140822...l%20Report.pdf
On 16 May 2011, an Airbus A330-343 of Cathay Pacific Airways took off from Singapore-Changi Airport on a scheduled flight to Jakarta. While climbing through 33,000 feet at 01:29 hours, the No.2 engine stalled and a loud bang was heard and vibration was felt by the flight crew. The flight crew shut down the No.2 engine, following which the vibration reduced, but did not disappear. The flight crew declared an emergency to ATC and flew the aircraft back to Changi Airport.
About 15 minutes after the initial No.2 engine problem, when the aircraft was at 10,500 feet and descending into Singapore, the No.2 engine fire warning indication appeared and the flight crew discharged an engine fire extinguishing bottle. The fire warning indication was cleared but re-appeared after 69 seconds.
The flight crew discharged a second engine fire extinguishing bottle but was unsure if the fire had been extinguished as the fire warning light flickered intermittently.
After the aircraft landed, the Airport Emergency Service saw fire at the No.2 engine as they approached the aircraft and proceeded to put it out. No one was injured in this incident.
The No.2 engine vibration was a result of the engine’s rotating assembly becoming unbalanced following the loss of a 130 mm tip section of one of the engine fan blades. The failure of the fan blade could be attributed to its mechanical strength having been compromised as a result of the use of an incorrect gas during the manufacturing process.
The interior of the No.2 engine fan case was damaged by the rubbing against it of the fan blades of the engine’s unbalanced rotating assembly. The severe rubbing generated heat resulting in the ignition of the Kevlar wrap of the fan case. The fuel pump supply line cracked due to high vibrations, resulting in fuel leak. It was likely that the heat from the burning Kevlar layers ignited the leaked fuel.
About 15 minutes after the initial No.2 engine problem, when the aircraft was at 10,500 feet and descending into Singapore, the No.2 engine fire warning indication appeared and the flight crew discharged an engine fire extinguishing bottle. The fire warning indication was cleared but re-appeared after 69 seconds.
The flight crew discharged a second engine fire extinguishing bottle but was unsure if the fire had been extinguished as the fire warning light flickered intermittently.
After the aircraft landed, the Airport Emergency Service saw fire at the No.2 engine as they approached the aircraft and proceeded to put it out. No one was injured in this incident.
The No.2 engine vibration was a result of the engine’s rotating assembly becoming unbalanced following the loss of a 130 mm tip section of one of the engine fan blades. The failure of the fan blade could be attributed to its mechanical strength having been compromised as a result of the use of an incorrect gas during the manufacturing process.
The interior of the No.2 engine fan case was damaged by the rubbing against it of the fan blades of the engine’s unbalanced rotating assembly. The severe rubbing generated heat resulting in the ignition of the Kevlar wrap of the fan case. The fuel pump supply line cracked due to high vibrations, resulting in fuel leak. It was likely that the heat from the burning Kevlar layers ignited the leaked fuel.
4.1.4 The engine manufacturer has launched modification design activities to increase the engine’s robustness in the event of a partial fan blade release.
I am somewhat dubious about the Boeing claim that such vibration is "unlikely to lead to further damage" when in this CX case it clearly did just that.
Duration of CX event - failure to on-the-ground - 28 minutes.
And, yes; they must have flown past Batam.
1.3.1.7 The pylon on which No.2 engine was mounted was found with several cracks. The pylon was removed and inspection revealed multiple cracks on the forward secondary structure which suggest the presence of high loads level. This damage was most probably consequential and due to the high engine vibration following the partial fan blade release. The pylon primary structure showed no signs of damage.
1.3.2 Fuel line
1.3.2.1
The No.2 engine fuel line next to the engine fuel pump (which supplied fuel from the wing fuel tank to the fuel pump) was found to have a 180° crack around the edge of the tube end-fitting weld
1.3.2 Fuel line
1.3.2.1
The No.2 engine fuel line next to the engine fuel pump (which supplied fuel from the wing fuel tank to the fuel pump) was found to have a 180° crack around the edge of the tube end-fitting weld
That more serious consequences did not eventuate is no guarantee that they could not have occurred at any time during that 1:45 turn-back..
Refer : https://www.mot.gov.sg/news/20140822...l%20Report.pdf
Last edited by WingNut60; 28th Jun 2017 at 16:05.
Join Date: Jan 2006
Location: US
Posts: 2,205
Likes: 0
Received 0 Likes
on
0 Posts
A330-200 at max landing weight requires 5600'(rounded up). SL. ISA std
A330-300 at max landing weight requires 5400'(rounded up).
777-200 needs 3900'(rounded up).
777-300 needs 4400'(rounded up).
737-800 needs 4100'.
A319 needs 4700'.
A320 needs 5000'.
A321 needs 5400'.
The lack of understanding by some of how 'ETOPS' relates (or otherwise) to this incident is a good example.
In the QF72 event, the Captain very quickly realised that the failures that were occurring were beyond his (and possibly most line pilot's) knowledge and experience base to make any decision other than to land at the nearest suitable (the non-aviation definition) airport.
Given the obvious level of vibration and with an engine inoperative, I'm surprised that this Captain felt he had the confidence in the aircraft and, among other things, it's structural integrity to go past a suitable airport significantly closer than Perth.
Maybe he did.
Maybe that's why he was praying.......
It seems not so much the point that the Captain flew for 103 mins PAST a strip suitable for the aircraft, not so much for the passengers or repair and recovery, but the fact that the failed engine was contributing severe vibration to the airframe and most likely the sole remaining engine on the other wing, it's pretty bad vibration if you can't bear to sit back against the seatback. If #1 had run out of oil and seized, then no vibration and to continue on to Perth would be a safe option.
Just for the record, it seems that he commenced his turn-back approx. 3 mins after the bang.
If there was any contribution from base that went into the decision then it was pretty punctual and brief.
If there was any contribution from base that went into the decision then it was pretty punctual and brief.
Spot on Dave, low frequency and very high amplitude, I'd be very surprised if this airframe isn't damaged, if it isn't then Airbus have gone up a notch in my estimation.
I'd be very surprised if this airframe isn't damaged,
It ain't the first time its happened across most fleets.