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Borescope Interval
In the aviation section of today's The Australian a Qantas spokesman is quoted as stating:
"The last borescope inspection was July 8. We do it every 750 flight hours, or roughly every six weeks..." Could somebody with QF RB211 knowledge please advise if this interval is normal for the engine maintenance program, or as a result of an airworthiness directive. |
Qantas no longer overhauls its RB211 engines. All the overhauls have been outsourced since last year to Hong Kong. They only have a minor repair capability remaining in Sydney.
No word where or when this engine was last overhauled? |
Cavedweller
The article in The Australian (see earlier post) has Qantas stating that it was overhauled in August last year. |
By LeadSled...does QF still do RR overhauls in Sydney any longer??, or has it been offshored ?? I can understand C & D check outsourcing (sort of) but I assume engines and airframes are on different maintenance cycles, particularly if a couple of engines go unserviceable over a short period of time, must be an operational nightmare, am I right or wrong? It just doesn't seem a good economical decision. By CAVEDWELLER.....Qantas no longer overhauls its RB211 engines. All the overhauls have been outsourced since last year to Hong Kong. They only have a minor repair capability remaining in Sydney. No word where or when this engine was last overhauled? Thanks for that, I have only just arrived back in Australia after 10 years away, I just didn't realise how reduced the engine overhaul capability is today in Australia at QF.....:ooh: Wow. A good point, where and when.... |
The last borescope inspection was July 8. We do it every 750 flight hours, or roughly every six weeks..." For example: combustion chamber distress would be looked at say 250 hours intervals and the engine could stay on the wing for a couple of years. |
Depleted Uranium
Bit off thread but someone else raised the depleted uranium topic. FAA has an interesting old Advisory Circular warning of possible poisoning due to ingestion of depleted uranium during accident investigation http://rgl.faa.gov/Regulatory_and_Gu...E/AC20-123.pdf. Manufacturers give similar stern warnings about production and installation of d/u balance weights. US Military of course insists there is no hazard to human health from all the depleted uranium munitions blasted over Iraq!
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djfingerscrossed
As far as I know RR has not lost the contract, I believe QF's A380s have Rolls-Royce Trent 900s |
The PA to the PAX by the Capt...........was this done prior to or after the engine was secured via the severve damage check?
Good job all round.:cool: |
In an engine failure of that magnitude, apart rom the obvious damage, what other damage would an engine typically suffer. I can imagie bearings would suffer a lot of stress from the imballance, would vibrational loads be transmitted forward to the compressor sections, hence damaging parts upstream?
Is there a protocol that dictates all components are scrapped or is a simple overhaul done and components that are still servicable returned to the parts pool. |
nomorecatering,
in catastrophic failures very little is ever reused - if anything. Best Regards, N1 Vibes |
Is there a protocol that dictates all components are scrapped or is a simple overhaul done and components that are still servicable returned to the parts pool. For the subject event in this thread I suspect that the engine will be returned to service after an overhaul. |
Are we absolutely sure this was an RB-211 powered aircraft? The last time I flew Qantas SFO-SYD, last year, the equipment in use was the Extended Range version of the 744, a 747-438ER. Judging by the length of the (very comfortable) journey, I think I worked out why.
And the engines on VH-OEH were, I think, General Electric CF6-80C2B5. |
Yes the aircraft has RB-211 engines.
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Engine RB211
Aircraft OJP RR RB211 Engines - nbr 4 engine overhauled in HKG last year, engine suffered failure nbr 3 bearing at 28000Ft on climb, had high vibes & then went EGT Amber 795 C. Turbines cut turbine overheat switches wiring & EGT when it let go. Believe engine is being sent back to HKG for strip investigation.
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D120A,
Qantas VH-OJ- series 747-400s are powered by RB211s. VH-OE- series are/were those bought from Malaysian and Korean and the 747-400ERs; all are powered by CF6s. |
#3 bearing? Do we mean the HP or the IP turbine bearing per chance...
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Good job done...no doubt about that!
:ok: |
Lomopaseo,
as prev mentioned depends on the type/nature of failure if the enigne is rebuilt or scrapped. RR recently told one operator, whose engine had experienced only a fan blade failure, that they would not be getting the enigne back. Best Regards, N1 Vibes |
Engine strip-down inspection
Believe engine is being sent back to HKG for strip investigation Seems a bit unlikely. Surely this will be considered a 'serious incident' or even an 'accident' and the engine strip-down would be under AAIB (UK engine) or NTSB (happened in the US of A, aircraft US-certified) or ATSB (Oz-registered aircraft) supervision. You'd be wanting a major engine plant with all the clever toys for metallurgy, electron-microscopy, etc. etc. So not an MRO, a main plant, so I'd be guessing RR Derby. |
Kiwi,
the AAIB travel to HKG, the HAESL facility strips the engine with AAIB and RR in attendance(Haesl has permanent RR staff onsite). Any clever metallurgy stuff is done in RR Derby. HAESL have done lot's of other incident investigation engines. Best Regards, N1 Vibes |
I bet an aussie beer that the clever metalurgy will be done in Canberra :)
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I'd suggest that if it'd been a CF6 it would be a real mess!!:uhoh:
G'day ;) |
An visual engine inspection following disassembly of the engine showed that all turbine blades had separated from the IP (intermediate pressure) turbine disk. The blades of the three LP (low pressure) turbine stages were fractured through the airfoil section of had separated from the disk. The LP stage nozzle guide vanes were destroyed, the remaining LP nozzles were substantially damaged. The LP turbine bearing and adjacent phonic wheel and speed probe were destroyed. The IP shaft was severed towards the aft end. Incident: Qantas B744 near San Francisco on Aug 31st 2010, uncontained engine failure |
ATSB Photo from Av Herald Article
http://avherald.com/img/qantas_b744_...o_100831_3.jpg
It shows the blades thrown off the IP and Stage I LP turbines -- along with the departure of a good chunk of the stator housing. Perhaps a solid piece got in the way of the blades and sheared them off:ouch: |
I'll propose another scenario - which may/may not be pertinent to the RB.
The fact that the IP SHAFT is sheared is very worrisome - and in fact that may be the initiating event. If this occured first, then the IPT is suddenly unloaded and very quickly overspeeds, since the N3 system continues to run and provide the gas flow. The overspeeding N2 turbine will at some point fail - and it's possible that the next part to break will be the IPT blade roots. The release of all the blades could rip open the case and the cowl, but then leave the IPT disc without a driving torque, so it does not burst (a very, very good thing!) Maybe someone more familiar with specific knowledge of RB failure modes can comment. |
Barit1
I'll propose another scenario - which may/may not be pertinent to the RB. The fact that the IP SHAFT is sheared is very worrisome - and in fact that may be the initiating event. If this occured first, then the IPT is suddenly unloaded and very quickly overspeeds, since the N3 system continues to run and provide the gas flow. The overspeeding N2 turbine will at some point fail - and it's possible that the next part to break will be the IPT blade roots. The release of all the blades could rip open the case and the cowl, but then leave the IPT disc without a driving torque, so it does not burst (a very, very good thing!) Maybe someone more familiar with specific knowledge of RB failure modes can comment I do agree that the shaft separation is troubling, more so because the visible unbalance of the IP rotor looks unlikely to to put much of a load on its drive shaft (chicken-egg question) The battered off LP blades sure look secondary to the IP debris, while the empty blade roots in the IP suggest either severe overspeed or fire and stretching of the disk. Sucessful design if the shaft was primary and the rotor disk remained intact:ok: |
lomapaseo - my assumption was that Ppruneists would translate my cryptic RB as RB211. Sorry for the excess brevity.
I also assumed it obvious that the downstream LPT damage is secondary. 99% of the time, that's the way the damage propagates. In any event, I'll be very curious to learn what the experts think. |
AFAIK, RB stands for RollsBarnoldswick? :confused:
G'day ;) |
Interesting. This article on the QF A380 Trent failure seems to confirm my speculation about the QF 747/RB211 failure. The two seem closely related.
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Interesting. This article on the QF A380 Trent failure seems to confirm my speculation about the QF 747/RB211 failure. The two seem closely related. While I might agree with you about what likely happened on the RB211, the only similarity that fits with the Trent incident is the Rotor location. Of course we could debate things like this in the more general Tech forum :) |
The QF74 failure and the QF32 failure are related.
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The QF74 failure and the QF32 failure are related. |
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