JayS wrote:Saying its "designed" for 12000hrs is also not correct. With the same matrix, F16 must be designed for 16000hrs or Gripen must be designed for 24000hrs. LCA is designed for 3000h, F16 is designed for 8000hrs and so on. That's correct way of saying it. Because these numbers are relevant as far as User is concerned.
No sir, BK is also correct, I would say more correct in this instance.
Any engineering product is designed with cushions, margins & tolerances. In essence you design for much more than you actually meant to.
Say you want to design a 70 ton bridge. As per stuatory rules, you design it with a safety factor of 4. That means you are actually designing the bridge for 70 × 4, 280 tons. All those columns, beams are designed for 280 tonnage, but mentiond as designed for 70 ton with safety factor of 4.(Becoz you were asked to build a 70 ton bridge, instead you designed the bridge for 280 tons)
And you would simply say i designed a 70 ton bridge.
While safety factor for bridge is 4, for aircrafts it is 1.5 as per US standards. (It may vary slightly from region to region) So general rule 1.5
Now BK mentioned figure of 12000 hrs & 3000 hrs.
12000 hrs / 1.5 (safety factor)= 8000 hrs (This is the amount of life hrs, all modern fighters aspire for)
It was mentioned by ADA officials, as LCA is a more of composite construction, there are adding more safety margin than usually meant for metals, which is 1.5.
So from BKs words, one can deduce ADA applied a safety factor of 4 AND REDUCED the life hrs FOR CERTIFICATION as 3000 hrs.
12000 hrs / 4 (LCA safety factor)= 3000 hrs.
(If its a pure metal structure, it would be 8000 hrs)But in effect they designed the LCA for 12000 hrs.
I guess this solves the mystery behind 12000 hrs fig.
And i just want to mention that, without going into the nitpicks, he raised some good points, I believe.