US carrier groups vs. europeans? Very very close?!?!

Haha! That was a good laugh…

Someone on this forum said they promised to fly on the first quarter of 2005. So, perhaps the last day of march? 🙂

regards,
Castor

Distiller, normally you make some kind of reinforcement around these cut outs, and as previously stated, you construct your load paths in such a way that they don’t come near these weak areas.

And when it comes to fibre in general, you have to calculate load paths in advance so that you know how you should put the fibre direction. In that way, you adapt the material to have very good properties in the load directions and weak properties in all other directions. If you’re not sure of the load path, or if you have loads coming from all kinds of directions you just put a 45 / 45 layered composite.

regards,
Castor

I get your point wys, and I can only say that our opinions differ. I think Seahawk sums it up pretty good – and I guess this is a question of philosophy.

The way I’m taught, and the way I feel, is that you should always try to keep your margin of safety as high as possible in order to be able deal with the unexpected. Ie, if you loose one engine and have a great chance of landing at a decent field (such as Salt Lake City, Calgary or whatever) and getting that engine fixed – you should do so. Because you never know what kind of problems can arise later on – and having one engine out just because you didn’t feel like getting the problem fixed at once when all these problems occur isn’t very smart.

I guess it will be quite interesting to hear FAA’s words regarding this flight.

best regards,
Castor

You can add ex Swe-AF Jas-39 Gripens (A, B, C & D) to that list as well.

But this is the case in twins all the time and yet that is considered acceptable risk. The margin of safety when flying a quad with one engine shut down is the same as that on a twin when everything is working normally so I don’t understand where the word ‘sloppy’ fits in.

Let me try to present my thoughts in another way;
If you have an ABS-system on your car, and if that system fails – there should be no problem in continuing driving your car since there’s other cars that don’t even have ABS-systems at all. Right? No. Because the reason to why the ABS-system was installed from the very beginning was to increase your margin of safety when driving on icy roads.

If I now may transfer this (somewhat twisted) example to the 747 I would say that just because you have four engine safety doesn’t mean that you should lower your margin of safety to that of a two engined airliner when problems arise. You should always make your best effort to maintain as high margin of safety as possible – this is your best chance to deal with unexpected failures/risks.

On a rolling three year cycle our training department makes us practice 2 engine out (on the same wing) descent, approach and landing and it really isn’t a big deal. Heck, we can even do 2 engine inop go arounds without any drama. If we needed to divert whenever a single engine failed there would be little point in having quads as all they would do is double your chance of a diversion!

Again, the four engines doesn’t just increase your chance of a diversion due to engine failure – but increases your chance of maintaining a great margin of safety. I believe you and I have different points of view regarding this issue. I’m probably being biased as being an aerospace engineer having served in the armed forces – and you as being a commercial pilot (?). 🙂

best regards,
Castor

Castor, flying 3 or 4 engined jets utilises a completely different set of thought processes when it comes to contingency planning when compared to the average twin (there are perhaps some minor differences to this when talking about aircraft designed from the outset for ETOPS such as the B777 and the A330).

Loss of an outboard engine on an A340 causes NO LOSS of any important system and loss of an inboard, despite resulting in the loss of one of the three hydraulic systems would not affect the way the aircraft flies at all (other than an increase in landing distance of 10% and a requirement to have visual contact with the runway by 50′ at the latest!). The cruise level would come down (not always the case on the A346!) and the fuel burn would typically increase by approximately 9% so as long as we have started with a sensible amount (not used our contingency, additional, etc) you can see that a single engine failure is not really a particularly big deal. If we were to lose a second then the story changes and we are now in the same boat as an A320 or a B757.

There are many more thoughts going through the flight crews heads than you can imagine however I think you can be fairly certain that the cost of passenger compensation is almost immaterial.

It wasn’t my intent to compare two engined airliners with four engined airliners in particular – but trying to tell bmused55 that the captain has the full responsibility for his passengers, not flight ops and certainly not the board of directors.

What I also wanted to point out was that loosing one engine on a 747 might not effect the plane’s handling characteristics that much – but it does reduce your margin of safety. Think about it; running on four perfectly good engines means that you’ll have to loose two engines in order to get into some kind of trouble. But running on three engines means that you’re only one engine failure away. So why do you want to reduce your margin of safety?

If this would have happend close to your destination I would understand continuing on three engines. But nearly a whole flight? If that isn’t an economic approach then it sure is a sloppy one.

best regards,
Castor

Its good that you’re not on the BA board of directors then isn’t it.

This situation does not warrant any kind of reprimand for the Captain. He spoke to BA ops for petes sake.

Are you trying to tell me that if you were a pilot on a 737 and ops told you to fly on one engine in order to save fuel – you would have done that? As a captain on a commercial airliner YOU have the responsibility of the passengers – not ops, not the board of directors and not your mother.