(B A) 747-400 question
I started another thread regarding crew family cockpit visits & whilst thinking about my next post , half remembered something , so here’s the question.
My 747- 400 cockpit experience was ONLY British Airways’ but I recall that many of them had a plaque / notice , reading ‘This aircraft is ... rated’. I think it was on the instrument panel , in the centre , but I’m not at all sure- and I think it related to the aircraft max’ speed. Could someone please explain what it was & what it meant? Thanks again! |
The placards said, “This aircraft is ‘G’ rated” or “This aircraft is ‘H’ rated” and they referred to the engine thrust rating. We had to check that the FMS engine rating was the same as on the placard. BA had a mixed fleet at the time, and they were worried that an FMS or engine could be re-fitted after repair that was incompatible. Intermix flying with two different ratings was not allowed.
The Rolls Royce RB211-524G had about 56,000 lbs of thrust and the 524H had about 60,000 lbs of thrust at seal level (if memory serves). I believe it was a fairly simple tweak of the EEC plus a pin change for the FMS which decided which rating was available. From about 2008 all engines on the fleet were de-rated to ‘G’s but the sims were all ‘H’s! Didn’t really make much difference in the grand scheme of things. Another mod introduced was the ‘Trent Core’, which reduced EGT and Fuel burn. Those engines were 524G/T or 524H/T. Hope this explains what you were asking about. |
Thanks eckhard , that’s explained it wonderfully!
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Originally Posted by eckhard
(Post 11252695)
The Rolls Royce RB211-524G had about 56,000 lbs of thrust and the 524H had about 60,000 lbs of thrust at seal level (if memory serves). I believe it was a fairly simple tweak of the EEC plus a pin change for the FMS which decided which rating was available.
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Thanks td’
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Thanks tdracer and you’re welcome Flugzeug A.
Another reason for the placard was that at that time we used paper manuals for take-off and landing performance. The manuals were also titled with ‘524G’ or ‘524H’ and to avoid mistakes, we had to check that the manual being used matched the placard in the cockpit. |
Ta once more eckhard.
I couldn’t find anything on the ‘net & was starting to think I’d imagined it. All fascinating stuff to the visitor on the jump seat : to you & the other crews , many thanks for having me. |
Originally Posted by Flugzeug A
(Post 11252551)
I started another thread regarding crew family cockpit visits & whilst thinking about my next post , half remembered something , so here’s the question.
My 747- 400 cockpit experience was ONLY British Airways’ but I recall that many of them had a plaque / notice , reading ‘This aircraft is ... rated’. I think it was on the instrument panel , in the centre , but I’m not at all sure- and I think it related to the aircraft max’ speed. Could someone please explain what it was & what it meant? Thanks again! |
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