787 SJC Cancellations
Apr 25, 2018, 3:47 pm
#16
Join Date: Nov 2017
Programs: BA, Hilton
Posts: 2,091
But there are others around these parts who are more knowledgeable about such matters, so hopefully they can confirm that or not.
Apr 25, 2018, 3:55 pm
#17
Join Date: May 2014
Posts: 7,237
The general yardstick is that BA will try and cancel as early as possible, barring obviously problems on the day.
Apr 25, 2018, 3:56 pm
#18
Join Date: Jul 2017
Programs: All the usual suspects
Posts: 342
I fly this route a lot and I have not been affected yet, which I know it's not much consolation at all if it happens to you. My colleague, who it did affect, got plenty of notice (weeks) and was re-routed to SFO which was a bit of a pain as he departed from SJC which meant he couldn't use his car to get to the airport. A re-route to SFO isn't the end of the world other than the immigration scrum if you don't have global entry, and a little extra commute time if you are actually heading into San Jose.
Apr 25, 2018, 4:41 pm
#19
Join Date: May 2016
Posts: 29
My colleague, who it did affect, got plenty of notice (weeks)
Apr 25, 2018, 11:23 pm
#23
Join Date: May 2014
Posts: 7,237
Because surely there would be an inspection of all potentially affected planes immediately, and any problems resolved then, or the aircraft halted until it could be resolved. In fact I thought that was why they grounded planes in January. I didn't expect them to be flying without even having been inspected. Unless you're saying they're all affected and the ongoing inspections are just risk management and they're pulling flights when the damage passes a certain threshold.
The airlines do what is told to them by the Safety regulators, EASA in BA's case. EASA's latest Airworthiness Directive on the case is 2018-0086 and states the following. All bolding are mine.
An occurrence was reported where, following N2 vibration and multiple messages, the flight crew performed an engine in-flight shut-down (IFSD) and returned to the departure airport, landing uneventfully. The post-flight borescope inspection of the engine revealed an intermediate pressure turbine blade (IPTB) missing at the shank. Analysis shows that this kind of failure is due to sulphidation corrosion cracking. This condition, if not detected and corrected, could lead to IPTB shank release, possibly resulting in an IFSD and consequent reduced control of the aeroplane.
To address this potential unsafe condition, RR issued Alert NMSB Trent 1000 72-AJ575 to provide instructions for engine removal from service when any IPTB with a high level of sulphidation exposure is identified by corrosion fatigue life (CFL) model. Consequently, EASA issued AD 2017-0056 to require removal from service of certain engines, to be corrected in shop.
Since that AD was issued, prompted by further occurrences and analyses, it was decided that, to reduce the risk of dual IFSD, a new cyclic life limit must be applied to certain engines [...]
Since that AD was issued, prompted by further occurrences and analyses, it was decided that, to reduce the risk of dual IFSD, a new cyclic life limit must be applied to certain engines [...]
Required Action(s) and Compliance Time(s):
De-Pairing of Affected Engines:
(1) For an aeroplane that has two affected engines installed: Before both engines exceed their respective IPTB cyclic limit, as specified in Appendix 1 of the NMSB at Revision 2, or within 20 flight cycles after the effective date of this AD, whichever occurs later, remove one of the affected engines from the aeroplane.
Affected Engine Installation:
(2) After removal of an affected engine, as required by paragraph (1) of this AD, do not install that engine on an aeroplane, except within the limitations as specified in Section 3.A of the NMSB.
Terminating Action:
(3) Modification of an affected engine in accordance with the instructions of RR SB TRENT 1000 72-H818 constitutes terminating action
De-Pairing of Affected Engines:
(1) For an aeroplane that has two affected engines installed: Before both engines exceed their respective IPTB cyclic limit, as specified in Appendix 1 of the NMSB at Revision 2, or within 20 flight cycles after the effective date of this AD, whichever occurs later, remove one of the affected engines from the aeroplane.
Affected Engine Installation:
(2) After removal of an affected engine, as required by paragraph (1) of this AD, do not install that engine on an aeroplane, except within the limitations as specified in Section 3.A of the NMSB.
Terminating Action:
(3) Modification of an affected engine in accordance with the instructions of RR SB TRENT 1000 72-H818 constitutes terminating action
Trent 1000-A, Trent 1000-C, Trent 1000-D, Trent 1000-E, Trent 1000-G, Trent 1000-H,
Trent 1000-AE, Trent 1000-CE, Trent 1000-A2, Trent 1000-C2, Trent 1000-D2, Trent 1000-E2,
Trent 1000-G2, Trent 1000-H2, Trent 1000-J2, Trent 1000-K2, Trent 1000-L2, Trent 1000-AE2 and Trent 1000-CE2 engines, serial numbers (ESN) as identified in Appendix 1 of the NMSB at Revision 2, except those that have embodied RR Service Bulletin (SB) TRENT 1000 72-H818 in service.
Trent 1000-AE, Trent 1000-CE, Trent 1000-A2, Trent 1000-C2, Trent 1000-D2, Trent 1000-E2,
Trent 1000-G2, Trent 1000-H2, Trent 1000-J2, Trent 1000-K2, Trent 1000-L2, Trent 1000-AE2 and Trent 1000-CE2 engines, serial numbers (ESN) as identified in Appendix 1 of the NMSB at Revision 2, except those that have embodied RR Service Bulletin (SB) TRENT 1000 72-H818 in service.
Apr 26, 2018, 1:13 am
#25
Join Date: Dec 2009
Location: Flatland
Programs: AA Lifetime Gold 1MM, BA Gold, UA Peon
Posts: 6,111
The actions required in the Directive are based on cycles (one takeoff/landing is one cycle) and BA (or anyone else) cannot precisely predict aircraft cycles in the longer term. Consider if an aircraft has a (unpredictable) medical diversion and is very delayed on arrival at its destination. Because it diverted it now accumulated 2 cycles instead of the expected one to get to that destination. Meanwhile some other aircraft which was expected to rest overnight at LHR is quickly set up for use to cover the flight the first aircraft should be operating if it wasn't stuck at its destination due to crew rest requirements. The second aircraft also gets another cycle (or two cycles) that was not expected.
If they're both 787s and BA is already short of aircraft, then there might be a cancellation further in the future when the engine of one of those aircraft reaches its cycle limit in the Directive, the engine is taken off and can't be re-used on another aircraft until RR supply parts to fix it. BA might have to run their aircraft very close to the Directive's cycle limit in order not to have even more cancellations - no airline has a lot of spare aircraft to handle some of them going sick.
If they're both 787s and BA is already short of aircraft, then there might be a cancellation further in the future when the engine of one of those aircraft reaches its cycle limit in the Directive, the engine is taken off and can't be re-used on another aircraft until RR supply parts to fix it. BA might have to run their aircraft very close to the Directive's cycle limit in order not to have even more cancellations - no airline has a lot of spare aircraft to handle some of them going sick.
Apr 29, 2018, 12:40 am
#26
Join Date: Sep 2012
Posts: 1,332
Apr 29, 2018, 1:06 am
#28
Join Date: Aug 2015
Posts: 540
Strange that sulphidation is such a life limiting factor on those IP blades. You can generally work around with coatings and temperatures to avoid it.
in saying that Jet A1 from certain countries has high sulphur content. Running the engine in a temperature sweet spot for type 2 corrosion might be something the design guys didn't factor correctly.
in saying that Jet A1 from certain countries has high sulphur content. Running the engine in a temperature sweet spot for type 2 corrosion might be something the design guys didn't factor correctly.