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Forum: Rotorheads
17th Nov 2018, 16:21
Replies: 18
Views: 3,124
Posted By Concentric

I thought you would appreciate that;). Also I...

I thought you would appreciate that;). Also I think topical to the OP's interest and location.
Forum: Rotorheads
17th Nov 2018, 14:32
Replies: 18
Views: 3,124
Posted By Concentric

Most of the time...

Most of the time (https://www.youtube.com/watch?v=pjosNPN0m98&feature=youtu.be).

https://www.youtube.com/watch?v=pjosNPN0m98
Forum: Rotorheads
24th Apr 2018, 10:37
Replies: 8
Views: 4,391
Posted By Concentric

Update...

Update (https://www.aibn.no/Aviation/Investigations/16-286) today from AIBN:

"A draft of the final report on the tragic accident near Turøy has been for consultation with the parties involved in...
Forum: Rotorheads
8th Nov 2017, 09:28
Replies: 212
Views: 97,425
Posted By Concentric

Whilst the desire to recreate actual operating...

Whilst the desire to recreate actual operating conditions inside a gearbox as faithfully as possible might at first suggest a whole-gearbox test, if that test were taken to failure it would not only...
Forum: Rotorheads
6th Oct 2017, 16:12
Replies: 212
Views: 97,425
Posted By Concentric

You might want to take another look at the voting...

You might want to take another look at the voting figures...
It doesn't take a maths guru to see that the voting trend is now more and more towards "No", currently 49% overall and that very few have...
Forum: Rotorheads
12th Aug 2017, 19:51
Replies: 43
Views: 9,391
Posted By Concentric

Riff, you might find this short presentation...

Riff, you might find this short presentation (http://aerossurance.com/wp-content/uploads/2016/01/2.4_Tamborini_Design-and-Development-Strategies-for-Main-Gear-Box.pdf) (download) from Leonardo...
Forum: Rotorheads
29th Jul 2017, 11:29
Replies: 212
Views: 97,425
Posted By Concentric

In Root Cause Analysis...

In Root Cause Analysis (https://en.wikipedia.org/wiki/Root_cause_analysis), the design features and detection or monitoring system failings you describe above would be regarded as causal factors but...
Forum: Rotorheads
27th Jul 2017, 10:11
Replies: 212
Views: 97,425
Posted By Concentric

SASless, Generally speaking, I am in...

SASless,

Generally speaking, I am in agreement that the definitive cause (or ‘root cause’ as I would prefer to call it) has not yet been satisfactorily explained or reported. The regulators...
Forum: Rotorheads
26th Jul 2017, 09:23
Replies: 212
Views: 97,425
Posted By Concentric

Their individual explanations are not mutually...

Their individual explanations are not mutually exclusive but in fact describe different phases in the failure sequence. That sequence is something of a chain reaction that ought to have been...
Forum: Rotorheads
23rd Jul 2017, 08:48
Replies: 212
Views: 97,425
Posted By Concentric

Would that include the Sikorsky S-92A tailrotor...

Would that include the Sikorsky S-92A tailrotor drive I wonder?
Forum: Rotorheads
20th Jul 2017, 17:06
Replies: 212
Views: 97,425
Posted By Concentric

I am afraid you have got me...

I am afraid you have got me there.:rolleyes::confused:
Forum: Rotorheads
20th Jul 2017, 16:04
Replies: 212
Views: 97,425
Posted By Concentric

Obviously there should be no silica inside the...

Obviously there should be no silica inside the gearbox. If it does get in there as contamination during gearbox module or mast installation, or during lubricant filling, its hardness might be a...
Forum: Rotorheads
20th Jul 2017, 10:13
Replies: 212
Views: 97,425
Posted By Concentric

RVDT, I have been wondering the same since...

RVDT,

I have been wondering the same since reading your post (http://www.pprune.org/3429369-post425.html) from 10 years ago.

I do think the lubricant is a very important and possibly...
Forum: Rotorheads
16th Jul 2017, 10:29
Replies: 212
Views: 97,425
Posted By Concentric

Whilst some testing is appropriate and I would...

Whilst some testing is appropriate and I would hope has been undertaken, I think just running the power train under sustained stress alone might not be the way to replicate the conditions that led to...
Forum: Rotorheads
10th Jul 2017, 16:09
Replies: 212
Views: 97,425
Posted By Concentric

There must have been some very major development...

There must have been some very major development between 28 June (https://www.flightglobal.com/news/articles/uk-caa-sees-no-prospect-of-quick-return-for-grounded-438857/) when the CAA released a...
Forum: Rotorheads
19th May 2017, 11:37
Replies: 1,915
Views: 1,410,429
Posted By Concentric

Gouli, Indeed, the crack has to be initiated...

Gouli,

Indeed, the crack has to be initiated somehow and it appears from the report that it was from one of a series of micro-pits 15mm - 16mm from the top face of the bearing, so all of them...
Forum: Rotorheads
19th May 2017, 08:49
Replies: 1,915
Views: 1,410,429
Posted By Concentric

I agree, the difference in face width is not the...

I agree, the difference in face width is not the only factor. But even the difference in Hertzian contact stress I believe may not be the only driving force behind this failure mechanism. Some...
Forum: Rotorheads
16th May 2017, 18:39
Replies: 1,915
Views: 1,410,429
Posted By Concentric

Possibly of greater interest than comparing FAG...

Possibly of greater interest than comparing FAG bearing spalling with SNR bearing spalling statistics over the same period, is to compare the information in 1.6.11.4 with that in 1.6.11.5. Excluding...
Forum: Rotorheads
16th May 2017, 07:17
Replies: 1,915
Views: 1,410,429
Posted By Concentric

I think we need to be careful not to conflate...

I think we need to be careful not to conflate spalling with ‘failure’. I am not even sure the term “less reliable” is appropriate either, as Time Since New is not listed against each unit withdrawn,...
Forum: Rotorheads
5th Apr 2017, 10:34
Replies: 1,775
Views: 971,711
Posted By Concentric

What I was hinting at was that ships use AIS to...

What I was hinting at was that ships use AIS to avoid collisions. The fishing boat with injured crewman had AIS but probably not the fancier systems CHC track their assets with. The S-92 transmitted...
Forum: Rotorheads
5th Apr 2017, 09:29
Replies: 1,775
Views: 971,711
Posted By Concentric

And for remote lighthouses...?

And for remote lighthouses...?
Forum: Rotorheads
4th Apr 2017, 20:26
Replies: 1,775
Views: 971,711
Posted By Concentric

Automatic PLBs have been standard issue for NS...

Automatic PLBs have been standard issue for NS Oil pax for many years. Sea Marshal is one make though there are others. Nowadays they are built into the lifejacket which for aviation is...
Forum: Rotorheads
17th Mar 2017, 20:14
Replies: 1,775
Views: 971,711
Posted By Concentric

The lighthouse may be unmanned but the rock is...

The lighthouse may be unmanned but the rock is not entirely 'uninhabited'. That may have been a factor, directly or indirectly.
Forum: Rotorheads
10th Mar 2017, 11:57
Replies: 1,915
Views: 1,410,429
Posted By Concentric

riff, One might assume it took a similar...

riff,

One might assume it took a similar magnitude of axial force to break 4 tabs on REDL as you can see in the photo below (Source AAIB Report 2-2011) but it is interesting that its gears stayed...
Forum: Rotorheads
8th Mar 2017, 20:03
Replies: 1,915
Views: 1,410,429
Posted By Concentric

Pretty straightforward really, FED, one or more...

Pretty straightforward really, FED, one or more chunks from the failed gear get carried forwards by the faster rotating sun gear and get entrained between the sun and those next 2 planet gears. With...
Showing results 1 to 25 of 87
 


 
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