marchie From United Kingdom, joined Apr 2010, 21 posts, RR: 0 Posted (2 years 6 months 2 weeks 4 days 15 hours ago) and read 15971 times:
This may be posted already but it has arisen in UK media this evening that EASA previously issued an airwothiness directive concerning the RR TRENT 900 engine on August 4th 2010. Indeed an interesting development.
Below is an excerpt taken from the document which I assume is in the public domain.
Here is a link to the full report document found on the Channel4 website.
ATA 72
Engine – Intermediate Pressure Shaft Coupling Splines –Inspection
Manufacturer(s):
Rolls-Royce plc
Applicability:
RB211 Trent 900 series engines, all marks, all serial numbers.
These engines are known to be installed on, but not limited to, Airbus
A380 series aircraft.
Reason:
Wear, beyond Engine Manual limits, has been identified on the abutment
faces of the splines on the Trent 900 Intermediate Pressure (IP) shaft rigid
coupling on several engines during strip. The shaft to coupling spline
interface provides the means of controlling the turbine axial setting and
wear through of the splines would permit the IP turbine to move
rearwards.
Rearward movement of the IP turbine would enable contact with static
turbine components and would result in loss of engine performance with
potential for in-flight shut down, oil migration and oil fire below the LP
turbine discs prior to sufficient indication resulting in loss of LP turbine disc
integrity. Some of these conditions present a potential unsafe condition to
the aeroplane.
This AD requires inspection of the IP shaft coupling splines and,
depending on the results, requires further repetitive inspections or
corrective actions....
UTAH744 From United States of America, joined Jul 2009, 170 posts, RR: 0 Reply 1, posted (2 years 6 months 2 weeks 4 days 9 hours ago) and read 15324 times:
Looks like the "smoking gun" to me. I wonder what EASA will come up with in the coming days. I appreciate your post as many replys on the other A380 threads are off subject, or wild speculation.
airportugal310 From United States of America, joined Apr 2004, 3056 posts, RR: 2 Reply 2, posted (2 years 6 months 2 weeks 4 days 9 hours ago) and read 15273 times:
Quoting UTAH744 (Reply 1): Looks like the "smoking gun" to me. I wonder what EASA will come up with in the coming days. I appreciate your post as many replys on the other A380 threads are off subject, or wild speculation.
Looks that way...must have been fairly obvious to mx engineers
gemuser From Australia, joined Nov 2003, 5217 posts, RR: 6 Reply 3, posted (2 years 6 months 2 weeks 4 days 9 hours ago) and read 15273 times:
Quoting marchie (Thread starter): This AD requires inspection of the IP shaft coupling splines and,
depending on the results, requires further repetitive inspections or
corrective actions....
Does the AD specify a time frame either by calendar or hours/cycles?
BMI727 From United States of America, joined Feb 2009, 14316 posts, RR: 26 Reply 4, posted (2 years 6 months 2 weeks 4 days 9 hours ago) and read 15237 times:
MD11Engineer From Germany, joined Oct 2003, 13334 posts, RR: 64 Reply 7, posted (2 years 6 months 2 weeks 4 days 1 hour ago) and read 14223 times:
Quoting UTAH744 (Reply 1): Looks like the "smoking gun" to me. I wonder what EASA will come up with in the coming days. I appreciate your post as many replys on the other A380 threads are off subject, or wild speculation.
It will only be a problem if RR or QF exceeded the maximum timeframe given in the AD for accomplishing this AD.
If the AD´s due date hasn´t expired yet or if the inspections have been carried out and nothing found within the legal timeframe, both QF and RR will be in the clear.
Baroque From Australia, joined Apr 2006, 15380 posts, RR: 60 Reply 9, posted (2 years 6 months 2 weeks 4 days ago) and read 13688 times:
Quoting MD11Engineer (Reply 7): It will only be a problem if RR or QF exceeded the maximum timeframe given in the AD for accomplishing this AD.
If the AD´s due date hasn´t expired yet or if the inspections have been carried out and nothing found within the legal timeframe, both QF and RR will be in the clear.
The odd thing is that Joyce has not THIS TIME referred to these ADs. Whereas they have been mentioned before in dispatches as it were! But it is difficult to attribute any significance to it. The unions would be sure to have mentioned it had neglecting these been a possible contributing cause. They would not miss a trick like that.
Burkhard From Germany, joined Nov 2006, 4248 posts, RR: 2 Reply 10, posted (2 years 6 months 2 weeks 3 days 23 hours ago) and read 13455 times:
First inspection has to be done after 400 cycles, which can mean a year almost. Issued in August, I doubt the A380 have already had the 150 cycles recommended in this in 70 days. So not having inspected this could still be within the directive, and LH still is safe of it anyways.
It would turn out that the directive was too optimistic...
Dizzy777 From Australia, joined Dec 2009, 91 posts, RR: 0 Reply 11, posted (2 years 6 months 2 weeks 3 days 23 hours ago) and read 13332 times:
15 Jan 2010 issue of the AD has the following further action tables attached (revisions of the AD give reference to procedure updates) and can be found at
Table 1.b: On-wing Borescope Inspection – Further Action and Repetitive Inspection Intervals
Condition
Measured spline crest in accordance with section
3.A of Rolls-Royce NMSB 72-AG329 Revision 1
is:
Action
Compliance Time /
Repetitive Interval (not to
exceed)
Less than 0,5 mm with no material remaining Remove the engine Before next flight
Less than 0,5 mm with some material remaining Remove the engine Within 10 flight cycles
Equal to or more than 0,5 mm but less than 1 mm Repeat inspection Within 50 flight cycles
Equal to or more than 1 mm but less than 1,5 mm Repeat inspection Within 100 flight cycles
Equal to or more than 1,5 mm but less than 2 mm Repeat inspection Within 200 flight cycles
Equal to or more than 2 mm but less than 2,4 mm Repeat inspection Within 300 flight cycles
Equal to or more than 2,4 mm (2) Repeat inspection Within 400 flight cycles
Note (2): The nominal unworn dimension of the spline crest is 2,65 mm.
Aesma From France, joined Nov 2009, 4782 posts, RR: 9 Reply 12, posted (2 years 6 months 2 weeks 3 days 22 hours ago) and read 13115 times:
Quoting MD11Engineer (Reply 7): It will only be a problem if RR or QF exceeded the maximum timeframe given in the AD for accomplishing this AD.
If the AD´s due date hasn´t expired yet or if the inspections have been carried out and nothing found within the legal timeframe, both QF and RR will be in the clear.
Jan
In the clear vis-à-vis the AD, but it would still mean (and even more) RR has a design or manufacturing problem !
New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
CFBFrame From United States of America, joined May 2009, 531 posts, RR: 3 Reply 13, posted (2 years 6 months 2 weeks 3 days 15 hours ago) and read 4175 times:
Quoting Aesma (Reply 12): In the clear vis-à-vis the AD, but it would still mean (and even more) RR has a design or manufacturing problem !
That may be true, and a design modification may be required long term. For most airlines, a mod is a nice thing to know will be coming but the challenge is establishing on wing time before engine removal. Since the fleets are so small, inspecting and replacing engines can have a major impact on a/c availability. Interesting this is the 14th a/c, so SIA will have a much bigger issue with this than QF. Maybe, with the larger fleet, SI has had the ability to inspect and replace easier than QF.
Stitch From United States of America, joined Jul 2005, 26693 posts, RR: 83 Reply 15, posted (2 years 6 months 2 weeks 3 days 15 hours ago) and read 3871 times:
Quoting Aesma (Reply 14): Someone said on another topic that SQ doesn't use its frames as much as QF.
SQ has had frames in service for a longer period of time, however, which might affect the flight cycle / flight hour count.
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