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Question for RJ drivers without VNAV

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Always deferred

Well-known member
Joined
Jun 5, 2003
Posts
175
A lot of the new optimized STARs in the NAS are being designed as Optimized Profile Descents, with at or above, at or below, and window altitudes designed to minimize level segments. (ex: FRDMM, TRUPS, EAGUL, etc)

Obviously these are more easily flown in VNAV, autothrottle equipped AC. My question for you drivers of CRJ 200/700 and legacy ERJ aircraft, how are you managing descents on these STARs while complying with the myriad constraints?
Is there a good rule of thumb, or are you pretty much flying the V/S wheel and hoping to make the restrictions?

Thanks
AD
 
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3-1 rule still works great. The "banana" is a nice back-up.
 
We have VNAV on the CRJ200/700/900. It's not autopilot coupled so its technically called Advisory VNAV. It makes ODPs simple and easy. We just follow the "snowflake" down using V/S
 
Right but if you have several consecutive constraints, aren't you doing a lot of "diving and driving" to make the next constraint? In otherwords, in an A320 for instance, you get a "descend via" clearance and you dial in the lowest alt on the arrival and the VNAV and A/P fly the aircraft to make each constraint. I would imagine in the RJ, you would be doing a lot of tweaking with the VS wheel making sure to hit at or below, at or above etc.
 
The VNAV advisory on the CRJ's is a LOT better than the one in the Boeing (or at least the old faithful rig I fly) there is no "diving and driving" in neither the arrivals nor in non-precision approaches. The only negative as someone posted is that you have to tell the autopilot to do what the advisory is indicating, but I can assure you it is a lot better.
 
The "snowflake" looks at the entire decent profile while the VNAV info displayed on the PFD looks at the next waypoint. Fly the snowflake and it should all work out.
 
Right but if you have several consecutive constraints, aren't you doing a lot of "diving and driving" to make the next constraint? In otherwords, in an A320 for instance, you get a "descend via" clearance and you dial in the lowest alt on the arrival and the VNAV and A/P fly the aircraft to make each constraint. I would imagine in the RJ, you would be doing a lot of tweaking with the VS wheel making sure to hit at or below, at or above etc.


The A320 does not have VNAV, if you have an arrival and set in the lowest altitude, the aircraft will keep on trucking along at your cruise alt until you push to managed the decent. True VNAV aircraft will start down on their own when VNAV is engaged.

It will give you the down hockey stick and tell you to decelerate when at TOD. but again will maintain cruise alt until you tell it otherwise.

Sucks if you ask me.
 
Putting the lowest altitude in and flying the snowflake works but you have to be paying attention (4eyeballs) and adjust VSI to hit the constraints along the arrival, even leveling off for a short time when the flake disappears and then continue the descent when it reappears. Seriously cuts into USAToday time...
 
Putting the lowest altitude in and flying the snowflake works but you have to be paying attention (4eyeballs) and adjust VSI to hit the constraints along the arrival, even leveling off for a short time when the flake disappears and then continue the descent when it reappears. Seriously cuts into USAToday time...

Yes on an arrival such as the FRDMM, you cannot just fly the snowflake.

And from what I understand, the ERJ doesn't even have the banana bar.
 
The "snowflake" looks at the entire decent profile while the VNAV info displayed on the PFD looks at the next waypoint. Fly the snowflake and it should all work out.

there is the rub. Absolutely no way to back yourself up other than being on top of your mental math from top to bottom. If you have an "at or above" or "at or below" it may put you right at the altitude, based on what it sees down the line on the ODP. All well and good until you are a little off the 'flake at just the wrong time. The guys who created these jacked up procedures arent going to be the ones getting violated if you miss an altitude......

PS: watch out for those speeds, they can throw the whole equation out the window......
 
Direct to page on FMS

Pull up the Dir to page on FMS and it will give you descent rate for all crossing restrictions. Vert speed and your all set to make all restrictions adjusting vert speed as needed
 
The A320 does not have VNAV, if you have an arrival and set in the lowest altitude, the aircraft will keep on trucking along at your cruise alt until you push to managed the decent. True VNAV aircraft will start down on their own when VNAV is engaged.

It will give you the down hockey stick and tell you to decelerate when at TOD. but again will maintain cruise alt until you tell it otherwise.

Sucks if you ask me.

I disagree. I'd like the airplane to go down when I want it to, not necessarily automatically at TOD. There are even times when ATC keeps you high, flying past the hockey stick. You still stay at your cruise altitude. Would a Boeing start down automatically? That could get you into trouble if you aren't ahead of the game. On the flip side of the coin, you can of course argue the SAN-MSP NWA Airbus would have never overflown MSP if they automatically started down on the hockey stick like a Boeing does.

Edit: Boeing has LNAV and VNAV modes that show up on the FMA, an Airbus does not. It has NAV (like nav in any other FMS jet), and it has a managed descent function which you have to push the altitude knob to activate. You do set the lowest altitude for the arrival and once at or near the hockey stick, start down. It'll hit all points and speeds, and give you advisories if it thinks it won't meet a certain waypoint constraint (like 'more drag' which to be honest is done with a horrible calculation and quite a few times it mentions that even when you don't technically need it). Overall, I'm satisified with the descent functions of the A320.
 
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I disagree. I'd like the airplane to go down when I want it to, not necessarily automatically at TOD. There are even times when ATC keeps you high, flying past the hockey stick. You still stay at your cruise altitude. Would a Boeing start down automatically? That could get you into trouble if you aren't ahead of the game. On the flip side of the coin, you can of course argue the SAN-MSP NWA Airbus would have never overflown MSP if they automatically started down on the hockey stick like a Boeing does.

Edit: Boeing has LNAV and VNAV modes that show up on the FMA, an Airbus does not. It has NAV (like nav in any other FMS jet), and it has a managed descent function which you have to push the altitude knob to activate. You do set the lowest altitude for the arrival and once at or near the hockey stick, start down. It'll hit all points and speeds, and give you advisories if it thinks it won't meet a certain waypoint constraint (like 'more drag' which to be honest is done with a horrible calculation and quite a few times it mentions that even when you don't technically need it). Overall, I'm satisified with the descent functions of the A320.

I am going to address you first part prior to your edit. You must not really understand true VNAV. I would never want an airplane to start down on its own because it reached TOD. I would though if I were CLEARED to descend VIA. if you trucking along at FL340 and have been cleared to descend at pilots discretion or VIA XYZ arrival in an airbus and set in your lowest alt the bus will maintain your cruising alt. Now in a boeing or any other plane with a coupled auto pilot and a true VNAV you set in your bottom alt WHEN CLEARED!!!! and the airplane will start down at the TOD.

You are correct you would get in a lot of trouble if we had airplanes with out clearance starting down to a lower alt with out pilots input. Come on man!
 
I disagree. I'd like the airplane to go down when I want it to, not necessarily automatically at TOD. There are even times when ATC keeps you high, flying past the hockey stick. You still stay at your cruise altitude. Would a Boeing start down automatically? That could get you into trouble if you aren't ahead of the game. On the flip side of the coin, you can of course argue the SAN-MSP NWA Airbus would have never overflown MSP if they automatically started down on the hockey stick like a Boeing does.

You don't understand how that works
 
But training says all you need is the snowflake and g/s x 5! Yeah, that doesn't work out so beautifully on any ODP. And leveling off??? I guess that's why these are ODPs and not CDPs.
 
Putting the lowest altitude in and flying the snowflake works but you have to be paying attention (4eyeballs) and adjust VSI to hit the constraints along the arrival, even leveling off for a short time when the flake disappears and then continue the descent when it reappears. Seriously cuts into USAToday time...

That's the only way to do it. I have been told that VPA 2.4-2.2 works to set up a continuous descent on the Freedom or Truups arrivals. Maneuver between the snowflake and bananna and have a lot of Pilot Deviation reports ready to file.
 
2.2 is more realistic. Saves the dive and drive nonsense, but requires math to figure the optimized angle. Too bad the angle isn't published on the charts
 
That's funny because the Honeywell FMS had one too?

Not all Honeywell FMS's have it. It is dependent upon whether that particular operator wanted that feature, which in turn increases the price so that Honeywell can pay Collins the appropriate licensing fees...
 
I am going to address you first part prior to your edit. You must not really understand true VNAV. I would never want an airplane to start down on its own because it reached TOD. I would though if I were CLEARED to descend VIA. if you trucking along at FL340 and have been cleared to descend at pilots discretion or VIA XYZ arrival in an airbus and set in your lowest alt the bus will maintain your cruising alt. Now in a boeing or any other plane with a coupled auto pilot and a true VNAV you set in your bottom alt WHEN CLEARED!!!! and the airplane will start down at the TOD.

You are correct you would get in a lot of trouble if we had airplanes with out clearance starting down to a lower alt with out pilots input. Come on man!

Thanks for the clarification. I have 0 time in a Boeing and don't know how their VNAV logic is.
 
In the ERJ the FMS has all the above/below altitudes loaded(which we obviously cross check with the chart). If you have the descent function setup at an appropriate angle for your wind conditions you just follow the VPI(pink glide slope) at the appropriate descent rate for your GS(which the FMS will give you a target, although its usually only a good target at TOD, then it fluctuates, but isnt accurate). You can also get into a maintenance page and see how high or low you are on the vertical path. I have made it a habit to set the bottom of each "window" into the altitude selector just to assure I dont bust the bottom and as long as I am on or under the VPI I will clear the top. Seems to work out ok, but you do end up, at least every time I have done them, shallowing at some point to like 1000fpm so you dont hit your final hard altitude like 20 miles early. Its not that hard, but you do have to pay attention.
 
When cleared "via", plug the bottom altitude, make sure the FMS has the correct altitudes programmed, and decend at the most restrictive rate when hitting "DIR INTC".

Works good, lasts long time.
 
The "banana bar" is a Collins proprietary feature.

May be proprietary, but as mentioned, doesn't have to have a collins set up to have it. The Dornier (both prop and jet) was designed/buit BEFORE the ERJ. Yet came with a more advanced PRIMUS avionics and but the same FMS. And the Dornier (both prop and jet) had the "banana bar" with the Honeywell FMS. The perf init page on the FMS that can ACTUALLY be programmed with various climb/descent profiles that the VNAV can be coupled to and follow. As opposed to the VNAV advisory of the ERJ. Flying these style arrivals in the that airplane required way less management. Simply set the LOWEST alt of the arrival and the VNAV won't violate ANY constraint between the TOD and that alt.

That's funny because the Honeywell FMS had one too?

See above.
 
XJT is starting an autopilot coupled VNAV test program with some our CRJ 900s, should be an interesting program

Sent from my HTC One X+ using Tapatalk 2
 
That's the only way to do it. I have been told that VPA 2.4-2.2 works to set up a continuous descent on the Freedom or Truups arrivals. Maneuver between the snowflake and bananna and have a lot of Pilot Deviation reports ready to file.

If you feel these arrival procedures present increased risk of PD, please file ASAP reports.
 

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