cessnalady
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FL 44 On A MEX-GDL Flight. Why?

Fri Dec 16, 2005 10:11 am

Flight AM 108 on Dec/13, on a sparkling-new B73NG (XA-HAM): We took off from MEX (Elevation: 7144 Ft) on this beautiful, clear, no-clouds day... and climbed, climbed, climbed and climbed. 15 minutes into the flight the FP announced we had reached our cruising altitude of 44,000 Ft... And then, just 8 minutes later, (i.e., at 23 minutes after take off), we started descent into GDL (Elevation: 5,100Ft), where we landed exactly 21 minutes later. We were airborne for exactly 44 minutes.

Does it make sense to take the a/c to such altitude for 8 minutes just to drop down again? I'd really like to learn... why would you do that?

Opinions, fellow pilots?

Marie
 
XA744
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RE: FL 44 On A MEX-GDL Flight. Why?

Fri Dec 16, 2005 10:29 am

Well, I am not a pilot, but could it have been a jet stream unusually traveling at between 25k to 35k ft ?

I was once on board a MAS 777 from EWR to DUB, and just when flying over Austria, the pilot requested ATC in VIE authorization to climb from 37,000 to 45,000 ft due to a jet stream that was on our path. I was in the cockpit and got this explanation from the FO.

Regards
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XA744
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RE: FL 44 On A MEX-GDL Flight. Why?

Fri Dec 16, 2005 10:31 am

Correction on the above please.

Trip was from EWR to DXB and then onto KUL, not to DUB

Regards
No matter how you fly...just never get your wings clipped !
 
stuckinMAF
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RE: FL 44 On A MEX-GDL Flight. Why?

Fri Dec 16, 2005 10:39 am

Hmm, not sure why it was so high either, but I know this is a typical Southwest flight profile in Texas, too. Going from MAF to DAL, HOU, or ABQ, we'll climb like crazy, level off at FL3x0 for about 10 minutes (A little longer to HOU), then begin decending. I guess that margin of efficiency at the high cruise altitude and the long decent makes up for the time spent climbing!
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EGTESkyGod
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RE: FL 44 On A MEX-GDL Flight. Why?

Fri Dec 16, 2005 6:54 pm

Sorry to be pedantic, but FL44 is 4,400ft, so 44,000ft is FL440. Could be anything. Traffic? Jetstream?
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ghost77
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RE: FL 44 On A MEX-GDL Flight. Why?

Sat Dec 17, 2005 1:27 am

Quoting EGTESkyGod (Reply 4):
Sorry to be pedantic, but FL44 is 4,400ft, so 44,000ft is FL440.

Sorry to be pedantic, but technically FL44 is not 4,400ft, that doesn't exist... ATC never mention you to decrease altitude to FL44.

Cessnalady - I'm sure this are efficiency test flights... you climb higher and faster with the B73G cruise faster and descent burning the less fuel... you gain more speed descending, save time and fuel!!!

ghost77 APM
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pr1268
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RE: FL 44 On A MEX-GDL Flight. Why?

Sat Dec 17, 2005 1:41 am

Just curious, I thought that the certified ceiling of the 737NG was FL410 and the 777 FL431 (43,100) feet (couldn't find those on Boeing's site, but I vividly remember reading those in a Jane's Aircraft book).

Granted, the planes are usually CAPABLE of flying higher than their certified ceiling, but doesn't that require some kind of bureaucratic process (variance from the airline's SOP or Pilot's Operational Handbook [POH])?

Also, don't these planes generally perform like crap at these rarified altitudes? I remember reading the TWA incident from April 1979 when the crew tried to extend the flaps 1 notch at FL390 (an unusually high altitude for the 727) to try to enhance the maneuvering performance.

Any others' thoughts?
The only time an aircraft has too much fuel is when it is on fire.
 
pr1268
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RE: FL 44 On A MEX-GDL Flight. Why?

Sat Dec 17, 2005 2:07 am

As for the really high short flights (reply 3), I've read that it is actually in the best interest of fuel economy to use the "bullet" profile (take off, climb unusually high, then descend) for short flights because the extra fuel used to climb higher is somehow offset by the savings of a longer, low-power descent.

Many South American airlines do it this way - LB, LA, PL, etc. especially on short-haul flights of 30 min - 2 hrs.

I did AUS-LAS on WN in May 2003 at FL390 - very nice flight indeed, plus my first flight in a 73G. Even when I did DAL-HOU on WN in 1999, we ascended all the way to FL330 for a 45 min. flight.

But, even WN can't get above FL250 even if they tried on a HOU-AUS flight these days (typically 25-28 minutes flying time).
The only time an aircraft has too much fuel is when it is on fire.
 
Fly2HMO
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RE: FL 44 On A MEX-GDL Flight. Why?

Sat Dec 17, 2005 2:30 am

Quoting Pr1268 (Reply 7):
As for the really high short flights (reply 3), I've read that it is actually in the best interest of fuel economy to use the "bullet" profile (take off, climb unusually high, then descend) for short flights because the extra fuel used to climb higher is somehow offset by the savings of a longer, low-power descent

Correct. They'll usually wait until the last possible minute to descend, and it will be a steep descent so the plane basically glides down with engines almost at idle.
 
Geo772
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RE: FL 44 On A MEX-GDL Flight. Why?

Sat Dec 17, 2005 3:20 am

Everytime I've flown on a 73G it has involved a cruise above 40,000ft. The shortest flight was about an hour and ten minutes and the longest a little under 2 hours.

In days gone by it was quite common for flight crews to fly at a constant power setting and just steadily climb during the flight. The BAC1-11 benefitted from this and especially the VC10 which could break through the 40,000ft barrier.
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pr1268
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RE: FL 44 On A MEX-GDL Flight. Why?

Sat Dec 17, 2005 3:54 am

Replying to Geo772 (Reply 9): The Concorde did it this way, if I remember reading about this in some article. The Concorde would flatten its ascent (don't dare call it levelling off) at around FL520 or so and Mach 2.01, and climb at around 80-100 fpm x 90 minutes or so, then begin its descent from around FL600.
The only time an aircraft has too much fuel is when it is on fire.
 
N1120A
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RE: FL 44 On A MEX-GDL Flight. Why?

Sat Dec 17, 2005 4:27 am

Quoting CessnaLady (Thread starter):
the FP announced we had reached our cruising altitude of 44,000 Ft...

No you didn't. The 73G's max certified altitude is FL410, 41,000 feet.

Quoting Ghost77 (Reply 5):
Sorry to be pedantic, but technically FL44 is not 4,400ft, that doesn't exist... ATC never mention you to decrease altitude to FL44.

There is no FL44, it is 4,400 feet or FL440 which is 44,000 feet.
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juventus
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RE: FL 44 On A MEX-GDL Flight. Why?

Sat Dec 17, 2005 8:25 am

Sometimes pilots accept higher altitudes if ATC offers them a shor-cut.
 
adriaticus
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RE: FL 44 On A MEX-GDL Flight. Why?

Sun Dec 18, 2005 2:18 am

Quoting N1120A (Reply 11):
No you didn't. The 73G's max certified altitude is FL410, 41,000 feet

I don't think it was you, but her who was on board that aircraft. You are nobody to discredit her saying.

Quoting Ghost77 (Reply 5):
I'm sure this are efficiency test flights... you climb higher and faster with the B73G cruise faster and descent burning the less fuel... you gain more speed descending, save time and fuel!!!



Quoting XA744 (Reply 1):
authorization to climb from 37,000 to 45,000 ft due to a jet stream that was on our path

I concur with Ghost and XA744. Our own a/c ver often do this maneuvers for the same reasons.

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luisde8cd
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RE: FL 44 On A MEX-GDL Flight. Why?

Sun Dec 18, 2005 2:29 am

I just flew MEX-MTY at FL380 in a Baby airbus. Isn't that too high for a 1 hour flight?

Saludos desde Caracas,
Luis
 
cessnalady
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RE: FL 44 On A MEX-GDL Flight. Why?

Mon Dec 19, 2005 7:56 am

Thanks for the different explanations; i.e., the "bullet profile", the jet streams, practice by other carriers...

Quoting EGTESkyGod (Reply 4):
44,000ft is FL440

I stand corrected. I could not edit the Topic line.

Quoting Adriaticus (Reply 13):
You are nobody to discredit her saying

Thank you very much.  Wink

Marie
 
Luis777
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RE: FL 44 On A MEX-GDL Flight. Why?

Mon Dec 19, 2005 10:45 am

Impossible for a 737-700 to flight above FL410 on a regular flight, I don't want to discredit anyone, It's clear, the flight envelope for a 737 NG is 41,000 ft and all the 737 NG pilots know that and never would fly their plane above its limitations, maybe it could fly higher but only on test flights made by Boeing, It's possible that the flight attendant made a mistake when she had to announce the flight level. She understood FL440 instead FL410.

Regards

LG
 
N1120A
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RE: FL 44 On A MEX-GDL Flight. Why?

Mon Dec 19, 2005 10:47 am

Quoting Adriaticus (Reply 13):
I don't think it was you, but her who was on board that aircraft. You are nobody to discredit her saying.

This has nothing to do with discrediting anyone, just to say that she may be confused. The maximum certified altitude for any 737NG aircraft (737-600/700/800/900) is FL410. This is 2000 feet higher than the A32S and 4000 feet higher than the 737Classic. If you go above FL410, you are in violation of the law, your insurance policy and good sense.
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gigneil
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RE: FL 44 On A MEX-GDL Flight. Why?

Mon Dec 19, 2005 12:07 pm

Quoting Adriaticus (Reply 13):
I don't think it was you, but her who was on board that aircraft. You are nobody to discredit her saying.

Well, except it doesn't matter who was on board the aircraft. The plane's service ceiling is 41,000 feet. It is illegal to operate it higher than that.

Hence, the plane wasn't there. Certainly not 44,000.

N
 
cessnalady
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 3:32 am

Now the fun has started...

Quoting Luis777 (Reply 16):
Impossible for a 737-700 to flight above FL410 on a regular flight

Not impossible. We were there.

Quoting Luis777 (Reply 16):
It's possible that the flight attendant made a mistake when she had to announce the flight level. She understood FL440 instead FL410.

.
The FP, not the FA, made the announcement... Together with a series of remarks pointing out cities (like Toluca and Morelia), external temperature (-64°C), and landscape features. As I said before, it was a remarkably clear day.

Quoting N1120A (Reply 17):
If you go above FL410, you are in violation of the law,

Nice and sharp dictum!!... And which jurisdiction is this that you seem to know so well? (Just FYI, we were in Mexican airspace). banghead 

Quoting Gigneil (Reply 18):
It is illegal to operate it higher than that.
Hence, the plane wasn't there. blockhead 


I should not even answer this stupid sophism (Reminded me KL 007 shouldn't have been where it was  Yeah sure )... But indeed my plane was there...

Or go tell the FP his altimeters were off for a few thousand feet!!

Marie
 
Airlinerfreak
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 3:36 am

Well often times through Mexico you find turbulent weather. I have found in on such flights from PVR-MEX multiple times. We have often had to make deviations or fly above the storms so weather could always be a possibility.
 
N1120A
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 5:51 am

Quoting CessnaLady (Reply 19):
And which jurisdiction is this that you seem to know so well? (Just FYI, we were in Mexican airspace).

It doesn't matter what airspace you were in. The 737NG is certified for a max altitude of 41,000 feet. That is what it is designed for, that is what Boeing recommended to all of the regulatory bodies and it is what the aviation authorities have certified it for. This is the same in Mexico as it is anywhere else

Quoting CessnaLady (Reply 19):
Or go tell the FP his altimeters were off for a few thousand feet!!

Or tell him he made a simple mistake

Edited to add this: http://www.boeing.com/commercial/bbj/flash/index_flash.html

That site gives you the max cruise altitude for the highest performance version of the 737, the BBJ. It is FL410, same as all other 737s.

[Edited 2005-12-19 21:59:25]
Mangeons les French fries, mais surtout pratiquons avec fierte le French kiss
 
adriaticus
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 6:08 am

N1120, Gigneil and CessnaLady have gone personal here. I think the point of the original question has been answered, made and well taken... Climb high to glide down with overall greater fuel efficiency, and/or avoidance of turbulencies / jet streams.

With reference to Boeing's manufacturer recommendation becoming the law everywhere... I wouldn't take that for granted. I am indeed an attorney for an airline, and I can attest there are many loopholes and omissions in that respect in many regulatory systems. Saying "it's the Law" just because Boeing "recommended" something, is, to put it mildly, far-fetched.

IMHO, that should be it.

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N1120A
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 6:13 am

Quoting Adriaticus (Reply 22):
Saying "it's the Law" just because Boeing "recommended" something

That is not what I am saying. I was stating that, in addition to FL410 being the max certified altitude of the 737NG by any regulating body in the world, it was also Boeing's recommendation.

Quoting Adriaticus (Reply 22):
I can attest there are many loopholes and omissions in that respect in many regulatory systems.

Max certified flight altitude is not one of them. It is not only in contravention of aviation regulations all over the world, it is also going to lose an airline their insurance policy on the aircraft. Further, given that AM leases many of their 73Gs, it will break their lease contract.

Quoting Adriaticus (Reply 22):
N1120, Gigneil and CessnaLady have gone personal here.

This is nothing personal, it is a correction of a mistake.
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nosedive
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 6:18 am

Quoting Adriaticus (Reply 22):
Saying "it's the Law" just because Boeing "recommended" something, is, to put it mildly, far-fetched.

It also is a great opening for a lawsuit!
 
ghost77
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 6:52 am

Quoting CessnaLady (Reply 19):
Not impossible. We were there.

Well, it's then time and place to disclose names, hours, flights and dates, Luis777 is a first hand ground instructor and responsible for all those AM73G pilots and more....

ghost77 APM
Ricardo Morales - flyAPM - ¡No es que maneje rapido, solo estoy volando lento!
 
gigneil
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 7:26 am

Quoting CessnaLady (Reply 19):
Or go tell the FP his altimeters were off for a few thousand feet!!

I'd be pleased to. As Ghost suggested, it would be awfully nice to know the name of said pilot that would risk his career, your lives, and Aeromexico's insurability.

Quoting Adriaticus (Reply 22):
N1120, Gigneil and CessnaLady have gone personal here.

Absolutely not, and I find the assertion somewhat ridiculous.

Flying up to and above the service ceiling of an aircraft killed those two Pinnacle pilots, some people on the ground, and destroyed a several million dollar CRJ.

N
 
BBJII
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 7:30 am

Quoting CessnaLady (Reply 19):
Impossible for a 737-700 to flight above FL410 on a regular flight

Not impossible.

The BBJ (which is a 700series) has a optimum Altitude of FL440.

We normally fly @ FL390 and not above, unless we van get a good tail wind to save fuel and time.


 wave 
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Luis777
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 7:33 am

I need proves, did you read the altimeters and were inside the cockpit?, besides maximum certified altitude is determined during certification and is usually set by the pressurization load limits on the fuselage, so, if you fly above FL410 on your sparkling brand new 737 NG surely would blow up like a fat balloon and explode, or by minimum you could damage the structure severely. Maybe the pilot was joking telling they were flying FL440, anyway 99% of travelers don't have any idea of an airliner parameters.

Regards

LG
 
N1120A
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 7:43 am

Quoting BBJII (Reply 27):
The BBJ (which is a 700series) has a optimum Altitude of FL440.

According to the FAA, all 737s, including the 737-700IGW on which the BBJ1 is based, have a maximum certified altitude of FL410. Other than the strengthened wing (738 wing), standard winglets, increased MTOW and fuel capacity, there are no differences in the airplane.
Mangeons les French fries, mais surtout pratiquons avec fierte le French kiss
 
MTY2GVA
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RE: FL 44 On A MEX-GDL Flight. Why?

Tue Dec 20, 2005 11:46 pm

If it happened congratulations your alive you should make a T-shirt that says " I survived flying at FL440 on a 737-700"  smile 
Tengo orgullo de ser del norte del mero San Luisito...
 
Tornado82
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RE: FL 44 On A MEX-GDL Flight. Why?

Wed Dec 21, 2005 12:01 am

Quoting Gigneil (Reply 26):
Flying up to and above the service ceiling of an aircraft killed those two Pinnacle pilots, some people on the ground, and destroyed a several million dollar CRJ.

They didn't kill anybody on the ground in that crash, and since when did they get above FL410 either?