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VNAV / cruise optimal altitude / step climb


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hello,

 

I am new to the CRJ (seventh flight) and,  being used to the AS Bus-es,PMDG and QW aircrafts, in the CRJ I don't know how to assess Step Climb / Optimal Altitude, along the flight plan

 

I'm sorry: I've read the manuals once, yet I cannot retrieve that info, as well as I could not find it after searching the forum

 

thanks

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There is no information on optimal altitudes or step climbs available to us. As the CRJ is a short range aircraft, step climbs usually don't happen.

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ok, then I how do I estimate the TOC / cruise altitude ? (I've rescrolled the manuals, I could not find any tables based on weight...sorry I am not an expert)

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On a lot of short-distance CRJ real world flights, the aircraft never even climbs to its optimal altitude in the first place. One R/W flight I have ridden on many times is a CRJ-900 from KELM to KDTW. I use that same flight for testing in the sim. It is 289 miles, and the aircraft could easily make the trip at FL340, but because of ATC restrictions the maximum altitude they are normally allowed to use is FL260. Some days they even go at FL240.

 

The longest CRJ flight I have ridden on a regular basis is from KDTW to KIAH, which is just over 1000 miles. That flight usually goes at FL360 and never steps any higher. Only once when I was on board did they fly it initially at FL340, and then stepped to FL360 later. It might have been due to ATC, or might have been because the aircraft had a full passenger load and it was summertime.

 

With the current Covid situation, I doubt that many r/w flights are carrying a full passenger load these days.

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Real world RJ driver here.

 

I've taken the -900LR from CYVR to KORD, and from CYYC to KIAH (4+ hour legs) and most of my flying falls within the 2-3 hour range. 

 

Our step climbs are manually calculated (unlike PMDGs auto-step climb from their FMS sneaky sneaky) using our performance tables that are incorporated in the speedcard booklet we use every flight (not part of aerosoft's offering). Usually we climb up as soon as our weight allows, temperature and winds aloft-permitting. Sometimes it's not worth it (climbing into headwinds), but the engines do really see the benefit with a drop in fuel flow somewhere in the 100lbs/engine/hr/2000ft climb. 8450

 

Fully loaded at MTOW (84,500) we will often start at FL330 or FL350, and make our way up to FL390 depending on density alt. FL390 isn't common, you need to be fairly light (not full pax, planned Fuel on Arrival sub-3000 lbs) otherwise the min maneuvering speed starts to bite you in the butt. 

 

As for estimating TOC, it doesn't reaaaallly serve much in the way of function outside the planning realm. It happens when it happens. ATC restrictions in the climb often push the actual TOC far back from planned, especially in the busier airspaces (EU, East coast NA)

 

Hope that sheds some light! 

 

 

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  • 1 month later...

Dunno why it came to mind, but I thought I'd share a funny we do in the cockpit. 

 

The TOC is so variable once you're actually in the air because of delays, we tend to joking congratulate ourselves for being "early" to cruise alt despite not being able to do anything about because we just fly the profile, and are knocked around by ATC.

 

Most of the time were maybe 2-4 mins slow to TOC (planes get old, don't give'r like they used to), and miles further than planned (20-60 miles downwind)

 

"You're 2 mins early, and 7 miles ahead of of schedule for TOC, great work, nice flying. Let me buy you a coffee!

*Pushes Flight Attendant call button*

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