philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Jul 18, 2016 8:50:41 GMT 1
The fact is that CSeries was delayed because of GTF failure, at least related to the following incident in May 2014 ... But this was another issue... That incident caused a minor delay only, while the programme is altogether two years late. What I meant is that both the CSeries and the MRJ were initially expected to fly long before the A320neo. |
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mfranjic
Final Assembly Line stage 1
Posts: 222
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Post by mfranjic on Jul 18, 2016 9:36:37 GMT 1
Thank you, for your instructive post, Mario. I suspect the P&W engine issues would have been found on the CSeries or the MRJ if both of them had not been delayed, leaving the A320neo test the 'Purepower' engine family for the first time in 'real life' conditions. The fact is that CSeries was delayed because of GTF failure, at least related to the following incident in May 2014: Bombardier CSeries flight testing halted after engine problem But this was another issue... It was, but after the incident related to the PW1524G engine of the Bombardier´s CSeries CS100 aircraft - MSN 50001, reg. C-FBCS (FF on 16. Sep 2013), that occurred during the conducting of the engine ground runs on 29. May 2014 (an uncontained turbine rotor failure), all the necessary modifications were implemented in the design of the PW1127G-JM geared turbofan engines installed on the Airbus A320-271N - MSN 6101, test reg. F-WNEO, the first flying prototype that first flew on 25. Sep 2014, almost four months after the Bombardier CSeries PW1500G engine´s related incident. Every deficiency, found at any of the engine series of the  PurePower PW1000G engine family, have resulted with the design modification(s) afterwards implemented in the other engines series´ (re)design ... Mario |
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pi88re
Preparation for Convoy
Posts: 32 
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A320neo
Jul 18, 2016 12:52:35 GMT 1
Post by pi88re on Jul 18, 2016 12:52:35 GMT 1
all the necessary modifications were implemented in the design of the PW1127G-JM geared turbofan engines installed on the Airbus A320-271N - MSN 6101, test reg. F-WNEO, the first flying prototype that first flew on 25. Sep 2014, almost four months after the Bombardier CSeries PW1500G engine´s related incident.
Every deficiency, found at any of the engine series of the PurePower PW1000G engine family, have resulted with the design modification(s) afterwards implemented in the other engines series´ (re)design ...
Mario Only 4 months from incident to first flight of engine incorporating all the necessary modification ! That is impressive...
Is it always that fast to change the design of a turbine rotor ? |
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mfranjic
Final Assembly Line stage 1
Posts: 222
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Post by mfranjic on Jul 18, 2016 13:32:05 GMT 1
Only 4 months from incident to first flight of engine incorporating all the necessary modification ! That is impressive...
Is it always that fast to change the design of a turbine rotor ? Because of the bad design / manufacture / material of the one of the oil seals, at some 75% of N1 (LP spool speed), oil under pressure began leaking into the torque box cavity from the mating surface between the flange of the oil feed tube for the No. 4 bearing and the TIC (Turbine Inlet Cooling) assembly. From that point, the leaked oil merged with the cooling airflow. The cooling air and the leaked oil transited through the torque box, through the nearby cooling holes, and into the rotor cavity … … when the temperature in the torque box surpassed the auto-ignition point of the leaked oil, the leaked oil ignited in the torque box. The resulting fire flowed out into the rotor cavity, following the cooling airflow out the nearest cooling holes, located in the bearing support assembly. The fire then impinged upon the front face of the rotor disk, overheating the web of the disk until centrifugal force led to failure from tensile overload… So, there was no need to ´change the design of a turbine rotor´ … just a certain sealing ... Mario |
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sciing
in service - 1 year
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A320neo
Jul 18, 2016 16:15:39 GMT 1
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Post by sciing on Jul 18, 2016 16:15:39 GMT 1
One reason why the seal broke was that the engine was shot down several times too fast during the test phase. After high power (>70%) the engine has to be on for at least 10 minutes. So the seal saw a much higher temperature than designed for.
BTW: The bowing issue for the A320neo was not seen on the CS-Series as said already in march by the UTC CEO. Core vs. nacelle mounting!
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XWB
in service - 11 years
Posts: 16,115
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A320neo
Jul 18, 2016 16:20:11 GMT 1
Post by XWB on Jul 18, 2016 16:20:11 GMT 1
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mfranjic
Final Assembly Line stage 1
Posts: 222
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Post by mfranjic on Jul 18, 2016 20:29:33 GMT 1
Very interesting article, but one might mistakenly conclude that the likelihood of the similar future events was prevented by the revised cool-down procedure and nothing else than that… ... after the cause of the incident was comprehended, Pratt & Whitney, besides revised cool-down procedure, increasing the pre-shutdown cooling and requiring notification to P&W when there is a hot shutdown, also proposed some engine modifications and recommendations, which included: - the addition of a metallic face seal, in addition to the Teflon C-seal, on the No. 4 bearing oil feed tube mounting flange; - a change in the material of the mounting bolts of the No. 4 bearing oil feed tube flange to enable higher torque on bolts; - the installation of thermo-couples to permit real-time monitoring of the LPT cavity temperature; - operational restrictions to limit the oil seal temperature to 260°C / 500 °F; - post-flight daily oil consumption monitoring; - operational restrictions in high outside air temperatures; - increased daily borescope inspections. I believe all these modifications were implemented in the PW1127G-JM engine´s design before the  A320-271N - MSN 6101 first flew four months after the Bombardier CS100´s PW1524G engine´s incident… Mario P.S. The article is only a part of the story. ´The full story´ (read: the truth) is well preserved and stored at the bottom of the Pratt & Whitney´s trays. Maybe it's for the best. Who is the one who has the right to claim that such a thing was predictable? That´s why all those testings exist. Thank God it happened during the ground testing and not during some test-flight or ... |
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Jul 27, 2016 11:47:50 GMT 1
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mfranjic
Final Assembly Line stage 1
Posts: 222
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Post by mfranjic on Jul 28, 2016 9:34:45 GMT 1
It will be interesting to see the dynamics by which will be able to deliver those modified and upgraded PW1100G-JM engines. Here is the link to the article:  .Mario |
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pi88re
Preparation for Convoy
Posts: 32
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A320neo
Jul 28, 2016 10:32:34 GMT 1
Post by pi88re on Jul 28, 2016 10:32:34 GMT 1
It will be interesting to see the dynamics by which will be able to deliver those modified and upgraded PW1100G-JM engines. Interesting as well to see how efficient will these 'golden' engines behave in service. Or shall we expect a 'platinium' engine in a few month? |
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