Short Haul Cruise

[Guest]

I know the 763 is a long-haul aircraft, but (notwithstanding ATC restrictions) for flights of, say, 1 hour (eg repositioning flights) is it better to climb to a high-level FMC optimum cruise for 15 minutes or so, or stay lower and cruise for longer?

[Guest ACA856_at_work3]

The answer depends on so many factors...weather/predictions, airline preference/procedures, ATC restrictions, traffic levels, etc, etc...All I can tell ya is from -1 hour or less- real world flights I have taken on 767's with Air Canada I can say the following:The idea is to climb as high as you can according to the STEP and/or Optimal cruise levels GIVEN the flight time you have available... For example, my regular 767 flights Toronto/Ottawa/Toronto is 30-40 minutes each way. The aircraft is generally very light so it could probably reach MAX altitude if it had enough fligh time to get there...the FMC would likely show a higher "optimal" altitude than we cruised at, but the legs page would show our TOD before we reached OPTIMAL altitude. In the 40 minutes flight, I typically see FL290 east and FL310 back west...the crew literally run up the isle to get the breakfast out before fianl approach. Another ACA 767 flight from Vancouver to Calgary (now scarebus I think), just over an hour flight, we went straight to FL410.Rob.

[Guest]

So straight up and straight down again with a cruise phase only if you can't go any higher?

[Guest]

You can use this chart, it comes from the 763 manual w/ PW engines.e.g Trip dist. 300nmtemp ISATOW brake release wt 285,000lbsshort trip cruise 35,000ft FL350

[Guest Dan_Pergau]

A few months before 9/11 I jump seated in a 762 from YOW to YYZ. We went up to FL310 for a few minutes and then started our descent right away ;) I miss those days.

[DShutt 14]

Okay Dan, don't mean to nitpick, but I'm confused (nothing new there eh?)...You miss:1. staying at 310 for a few minutes?or2. starting a descent right away?or3. jump seating in a 762 from YOW to YYZ (most likely BEFORE 9/11)?Language is everything, Dan, and I just want to be clear what it is you miss.:0PS You can kick me in the pants next time you see me - boy, do I miss that!DS CVA3339 / UKD149http://vatsim.pilotmedia.fi/statusindicato...tor=OD1&a=a.jpg

[Guest Dan_Pergau]

Hi Daryl,After further reflection I believe I miss all 3. As much as it would be fun, I don't recall ever kicking you in the pants... perhaps you have me confused for someone else? I will note your invitation for the said "kick in the pants" for future reference.Thank you for clarifying that!

[Guest ACA856_at_work3]

It is usually about a 10 minute cruise on the CYOW-CYYZ hop, most of the time is going up or down. On the CYVR-CYYC hope, we reached FL410 in about 15 mins, spent about 25 mins at cruise, the last part of the hour going down.Rob.

[Guest hvanleusen]

In July 2000 my wife and I where invited to the cockpit of an Ansett 762 on a one hour trip from Brisbane to Sydney. To my surprise the altimeter showed 39000 ft. The look outside at the terrific Goldcoast made it hard to stay looking at the Instruments. Needless to say the panel was in a well known manner.Hmmm.... I

[Guest Matthias1975]

@ hvanleusen :No way dude, 767PIC was released march 2001. Definitely not 2000!!Matthias

[Guest HPSOV]

From a fuel efficiency point of view its best to go as high as you can, even if this means a very short or non-existant cruise. In reality though this places too hiogh a workload on both flight and cabin crew, so often you will level off lower, to give yourself a 10 minute or so cruise segment.

[Tabs 2,790]

Yeah but if your fuel flow is actually higher due to the climbing up to the optimal altitude, it seems you'd reach a certain point where the cost of the power required to continue climbing would outweigh the efficiency gains right?Ryan

[Guest ilh]

I was doing some analysis with FSBuild2 last evening between KBOS and KJFK. If I chose an altitude that resulted in mininimal cruise time (e.g., FL260) it said I would use a fair bit more fuel than if I cruised at FL180. I don't know if that difference is realistic, a function of PIC, or a function of FSBuild.Lee Hetherington (KBED)http://vatsim.pilotmedia.fi/statusindicato...tor=OD1&a=a.jpg

[Guest Ian_Riddell]

>Yeah but if your fuel flow is actually higher due to the>climbing up to the optimal altitude, it seems you'd reach a>certain point where the cost of the power required to continue>climbing would outweigh the efficiency gains right?But wouldn't this be offset by the extra time spent in idle during descent? :-)For info.... The FMC has a PERF FACTORS or AIRLINE POLICY page which allows you to enter a value of 1 to 20 minutes (as a minimum cruise time). This affects the Optimum Altitude display on your VNAV CRZ page. As I recall, ours is set at 1 minute... as are many other airlines. If most airlines are aiming for efficiency (fuel savings), then this may indicate that it is indeed good to go your optimum altitude, even if it is only for a minute.Cheers.Ian.

[Guest Lenny Zaman]

ahhh, so we found another item for the future of PIC ;)Cheers(i always climb as high as possible, if ATC allows of course, f.e. EBBR-EDDF has a max of FL240, so we cannot go higher, we could but would have to descent to FL240 by the transitioning to Langen Radar...Now i have that chart, seems nice :))