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Re: was Arcjet, now solid boosters




>>
>>At 07:39 PM 6/4/2001 , you wrote:
>>>Especially maintenance.  The airlines have long known that the per-unit
>>>cost of jet engine maintenance is the same whether the engine is 20000,
>>>50000, or 90000 pounds thrust.  Labor cost is the driving factor here,
>>>not parts cost. This is the overriding reason why the Boeing 777 has
>>>only two engines (or so a GE employee told me a few years ago).
>>
>>Over the USA if you lose one of those engines you can make an emergency
>>landing ... hopefully.
>>But over water to Hawaii and you will go swimming, there is no backup or
>>place to land. You can only ditch at sea. If it at night (like coming back
>>from Hawaii usually is) then you go into the water in the dark, not a very
>>pleasant thing to consider.
>>
>>W4SCO
>
>Well...lets sort out Apples from oranges...first lets talk about two 
>engine airplanes (turbojets).  Two engine jet airplanes operating over 
>water must meet ETOPS requirements and be within certian distances from 
>land AT ALL times.  These numbers have gotten larger as the reliability 
>and record keeping on large turbofans has gotten larger.
>
>But in terms of an engine failure the remaining jet (and the pilot) doesnt 
>really care wheather or not they are over water or over the Rocky 
>Mountains (indeed under certian circumstances I would rather be pushing 
>the mighty twin (the triple seven) across the mighty water (the Pacific) 
>then say the little twin (the B-737) over the Rockies...
>
>Put it another way if you have to shut down an engine at the PNR (the 
>point of no return) from KLAX to KHOU in a 777 or 767 or 757 or 737 the 
>passengers would only know it because a prudent captain would put the vest 
>on etc...it wouldnt be any more or less exciting then losing one from KLGA 
>to KLAX....it just would take you a little longer to land (landings over 
>land must be made within one hour if you have an engine failure in a twin) 
>whereas it might take a little longer over the water...but statistically 
>you would still be as safe...ie the chances of losing the other one as 
>remote and the airplane would fly quite nicely (indeed you wouldnt have to 
>get over those nasty mountains).
>
>In short twin engine ops over water is NBD (no big deal)...Ditching in an 
>airplane with wing mounted turbofans is quite unlikely to occur 
>successfully either day or night.
>
>Four engines are a little different (ie the range rates are based on 1 
>out) and three engines are based on 1 out.  Its a myth that you could lose 
>three in a B-747 and continue to Honorroo.
>
>BTW my better half is right this instant pushing a B-767 across the mighty 
>waters to Honorroo...for a major US airline.  She is a training captain there.
>
>Robert Oler WB5MZO
>
>ATP (thats airline transport pilot) with ratings B-777, B767/757, B-737, 
>B-727, B-707, B-747 (100,200,300, 400). and I am a designated examiner in 
>a couple of them. CFII/MEI I have over 17,000 hours flight time.  My other 
>airplane is an F-14D Tomcat (and I am a Naval Fleet Instructor).

The Tomcat is a cool airplane ... you have two side by side engines. Would 
you like to lose one at 40,000 feet and then have to fly with minimal 
instruments thru 1200 miles thru a level 5 huricane in the dark?   I assume 
Boeing tried this feat with the 777 in order to get certified to fly the 
Pacific to Hawaii from the mainland. Hopefully they can balance the load by 
pumping fuel between the wing tanks?

 From the passengers view if they are on a 777 at night high over the 
Pacific in a bad storm and the pilot tells them that he "lost" an engine 
and to put on your life vest, I doubt you will have a very happy ride for 
the next 3 hours... remember you were 2 hrs from the nearest land with both 
engines, now you lost one so your speed decreases ... you lose altitude and 
perhaps run into higher head winds at a lower altitude. I would rather be 
over the rockies ... 4 or 500 miles from a major strip with many smaller 
strips even closer. Always safer to put it down on a level piece of land 
(even the Great Salt Lake) than to attempt a diching at sea with waves in 
the dark. Remember going to Hawaii you are out of radar contact. No one 
knows where you are unless you tell them. But now with GPS I wonder if 
there is a way to track planes like Onstar can track vehicles on land?

I luckily have never had an emergency in flight. But I have been on a Delta 
flight where both the primary and backup navigation systems failed at the 
gate and had to be replaced. We then taxied out and before we took off both 
new systems failed. We had to go back to the gate and replace both systems 
again. Took at 2 extra hours before we took off. Lucky for me it happened 
on the ground and not 1200 miles from land. Thats why when I fly myself I 
take a portable NAVCOM in my bag of goodies in case those on the plane 
fail. I was up with an instructor once and all nav systems on the Skyhawk 
failed. Luckily we could still talk to the tower and they helped us land 
with their radar. I was a board member of our flying club and we maintained 
the planes well at our military flying club.
I was an Army officer [non flying]. I always considered the Navy to be 
great. Keep up the good work.


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