Route following and AP modes for Speed

[Mad_X 12]

Hi there

thought to bring this over from the Facebook group. 

I have two main topics I want to discuss because I do not know if they are a bug or a feature (e.g. the real plane also behaves like this). Maybe some of the real Maddog drivers can shed some light on to this. 

1. Route following 

a) When entering a STAR it sometimes happens that the planes goes of track. My observation was, that while entering the STAR sometimes the plane just continues going on the current heading and does not consider the active waypoint. You than have to bring it back to that waypoint with the DIR INTC. Or it just goes in circles.

b) "Direct To": From what is learned the system is different from Boeing in such a way that when bringing a waypoint in the legs page "on top" the Boeing turn to that waypoint directly. But in the MD-80 you have to set an intercept heading to the planned track. In case you want to go directly to a waypoint from were you are you use the DIR INTC and select the waypoint you want. Are both statements correct? What is hte correct procedure in both cases?

c) DIR INTC: related to b): When you enter a 'direct to' to a waypoint currently not on your flightplan you obviously get a disconnect. But in NAV mode the plane just will turn hard and wants to fly in circles until the disconnect is gone. Then you have to bring it on track with a heading intercept. Is that a bug or real behaviour? How to deal with when such an input is necessary (quite often on VATSIM)?

2. AP Speed modes 

I understand the operation of the IAS mode for the vertical profile with the active clamp. What I do not know so far is the SPD mode on the AP and its fine behaviour. Do you only use it in level flight when not controlled by the FMC? And do you control speed climb and decent if not managed by the FMC with the VS(+SPD mode) or IAS mode? 
Also, how to operate the plane correctly (I mean real) on the final decent to the IAF for example. Do you decent with IAS or with VS(+SPD mode)? Or something else? Because I noticed that, when trying to control the speed during that phase of flight with SPD, it has a hard time to slow down. This makes we wonder because the Maddog is known for its ability to slow down pretty quick during the approach. Any realistic insight is welcome :)
 

In addition to the above, what is the strategy when decending? Always IAS mode? Because when putting my trust into the VNAV I always end up to high and to fast. I heard that this is something the real plane also does?

 

Thank you very much :)

[thibodba57 462]

22 minutes ago, Mad_X said:

2. AP Speed modes 

I understand the operation of the IAS mode for the vertical profile with the active clamp. What I do not know so far is the SPD mode on the AP and its fine behaviour. Do you only use it in level flight when not controlled by the FMC? And do you control speed climb and decent if not managed by the FMC with the VS(+SPD mode) or IAS mode? 
Also, how to operate the plane correctly (I mean real) on the final decent to the IAF for example. Do you decent with IAS or with VS(+SPD mode)? Or something else? Because I noticed that, when trying to control the speed during that phase of flight with SPD, it has a hard time to slow down. This makes we wonder because the Maddog is known for its ability to slow down pretty quick during the approach. Any realistic insight is welcome :)
 

In addition to the above, what is the strategy when decending? Always IAS mode? Because when putting my trust into the VNAV I always end up to high and to fast. I heard that this is something the real plane also does?

For reference refer to your Procedures and Techniques PDF (Chap 3 page 5) provided with the software.  This is assuming you are not using VNAV (easy mode ).  Initial IAS bug was set for V2+10.  The initial pitch reference after TAKEOFF is V/S.  1500' select CL on the TRP.  3000' roll the V/S to 1000' (This starts the aircraft to accelerate) then select IAS bug to 250IAS.  Upon reaching 250IAS select IAS/MACH on the MCP.  This switches back the aircraft pitch reference to IAS.  At 10,000' change the pitch reference IAS to 310 (or whatever speed you are looking for) then select the speed bug to the same value.  Upon reaching your Mach transition point (where Mach and IAS match) press the IAS/MACH button again and press the Speed bug knob one time (Speed bug Mach should be set prior to departure).  When you reach your Armed Altitude the aircraft will go to ALT HLD and the Throttle mode should switch to the selected Mach.  As will all things Maddog related.  Its very very important to pay attention to what the FMA is displaying.  This aircraft has a tendency to do stuff you don't intend.

Descents should be done in V/S.  You can play with IAS if you want, but it will be "quirky".  Select your desired descent speed for autothrottle management and vary your V/S to maintain that speed if the power levers are at idle.  This may require Speed Brakes.  As far as drag goes, this aircraft will slow down the moment it starts to get dirty.  Proper planning and technique applicable.  It will take practice.

 

For descents from cruise.  I plan 3:1 +15NM.  This will give you a bit of play room for deceleration.  Descend in V/S with the selected speed you want.  Don't forget the mach transition.  The VNAV is along the lines of the first Generation, and the automation of the aircraft is more of a 2nd generation of automation.  Its a bit tricky and requires a lot of attention.  Its not the hands off flying of any of the other aircraft available for flightsim.  Trust but ALWAYS verify what its doing.  You can verify the descent using the 3:1 rule mentioned before (ie 30,000' to descend is 90NM).

Hope this helps some.

Edited February 23, 2018 by thibodba57

[Mad_X 12]

12 minutes ago, thibodba57 said:

For reference refer to your Procedures and Techniques PDF (Chap 3 page 5) provided with the software.  This is assuming you are not using VNAV (easy mode ).  Initial IAS bug was set for V2+10.  The initial pitch reference after TAKEOFF is V/S.  1500' select CL on the TRP.  3000' roll the V/S to 1000' (This starts the aircraft to accelerate) then select IAS bug to 250IAS.  Upon reaching 250IAS select IAS/MACH on the MCP.  This switches back the aircraft pitch reference to IAS.  At 10,000' change the pitch reference IAS to 310 (or whatever speed you are looking for) then select the speed bug to the same value.  Upon reaching your Mach transition point (where Mach and IAS match) press the IAS/MACH button again and press the Speed bug knob one time (Speed bug Mach should be set prior to departure).  When you reach your Armed Altitude the aircraft will go to ALT HLD and the Throttle mode should switch to the selected Mach.  As will all things Maddog related.  Its very very important to pay attention to what the FMA is displaying.  This aircraft has a tendency to do stuff you don't intend.

Descents should be done in V/S.  You can play with IAS if you want, but it will be "quirky".  Select your desired descent speed for autothrottle management and vary your V/S to maintain that speed if the power levers are at idle.  This may require Speed Brakes.  As far as drag goes, this aircraft will slow down the moment it starts to get dirty.  Proper planning and technique applicable.  It will take practice.

 

For descents from cruise.  I plan 3:1 +15NM.  This will give you a bit of play room for deceleration.  Descend in V/S with the selected speed you want.  Don't forget the mach transition.  The VNAV is along the lines of the first Generation, and the automation of the aircraft is more of a 2nd generation of automation.  Its a bit tricky and requires a lot of attention.  Its not the hands off flying of any of the other aircraft available for flightsim.  Trust but ALWAYS verify what its doing.  You can verify the descent using the 3:1 rule mentioned before (ie 30,000' to descend is 90NM).

Hope this helps some.

Thanks a lot. So basically it is Q400. Always tries to kill you. I like that :). All the other are boring, aren't they ;)

Anything on the NAV questions you can shed light on? :)

And how do you control speed during approach (even with AP still on), manual throttles? 

[thibodba57 462]

1 minute ago, Mad_X said:

 

Anything on the NAV questions you can shed light on? :)

And how do you control speed during approach (even with AP still on), manual throttles? 

Still trying to digest the Nav related question honestly.  A lot of thinking and I'm trying to learn how to use FS2Crew properly :-)   I'll look it over again in a bit and get back if I can provide any input.  The aircraft I flew professionally had a different CDU than this one.  So its a bit different for me to use it as well.

Speed should be controlled via the Speed Bug and Autothrottle system.  Of course you can take off the Autothrottle whenever you want though.

[regis9 4,014]

1 hour ago, Mad_X said:

Thanks a lot. So basically it is Q400. Always tries to kill you. I like that :). All the other are boring, aren't they ;)

Lol I had a similar thought.  Normally when I get cocky thinking I’m an awesome virtual pilot with boeings and airbuses I fly the q400 to bring myself back down to earth (sometimes literally and in less of a controlled manner than I’d prefer!).  Now the maddog will be another aircraft for that purpose!

[McDaniel 48]

I have exactly the same challenges with route following, also on long straight legs, my route deviates from the line over time. Ticket submitted.

McDan out

[DaveCT2003 1,820]

On 2/23/2018 at 0:19 PM, Mad_X said:

So basically it is Q400. Always tries to kill you. I like that :)

LOL!

So there is a hidden point here.  A lot of non-pilot/flight simmers aren't aware of how much Pitch Over Speed is used. This is the principal used not only in IAS climb (set power, and use Pitch to control Speed) but in VNAV as well (it's just that the computer does it for you, taking into account crossing restrictions of course).

Like the Q400 and smaller regional aircraft, the Maddog is just a true pilot in control aircraft. They all have digital flight decks, but the main computer is the pilot.  From what you wrote, I'm guessing you're one of "us", people who really like that!  There are a lot more than we know, closet masochists! 

Regarding your Nav on Arrival/Approach question, Brian alluded to it in his post above.  Controlling your speed during this phases will make all the difference.  If you can provide the Arrival and Or Approach I can give you some idea of what I mean.

Best wishes.

 

[thibodba57 462]

On 2/23/2018 at 8:43 AM, Mad_X said:

Hi there

thought to bring this over from the Facebook group. 

I have two main topics I want to discuss because I do not know if they are a bug or a feature (e.g. the real plane also behaves like this). Maybe some of the real Maddog drivers can shed some light on to this. 

1. Route following 

a) When entering a STAR it sometimes happens that the planes goes of track. My observation was, that while entering the STAR sometimes the plane just continues going on the current heading and does not consider the active waypoint. You than have to bring it back to that waypoint with the DIR INTC. Or it just goes in circles.

b) "Direct To": From what is learned the system is different from Boeing in such a way that when bringing a waypoint in the legs page "on top" the Boeing turn to that waypoint directly. But in the MD-80 you have to set an intercept heading to the planned track. In case you want to go directly to a waypoint from were you are you use the DIR INTC and select the waypoint you want. Are both statements correct? What is hte correct procedure in both cases?

c) DIR INTC: related to b): When you enter a 'direct to' to a waypoint currently not on your flightplan you obviously get a disconnect. But in NAV mode the plane just will turn hard and wants to fly in circles until the disconnect is gone. Then you have to bring it on track with a heading intercept. Is that a bug or real behaviour? How to deal with when such an input is necessary (quite often on VATSIM)?

 

Sorry to get back to this so late.  

A) Sounds like a bug.  Report your Sim, route and what happened in a ticket.

B) If you want to go direct to point, you shouldn't really have to reorientate the aircraft prior to.  Obviously there are numerous ways to skin the cat, but unless your more than a 90* turn to the fix you want to fly to simply, Direct page, select waypoint in Scratch pad, LSK6L confirm>Exec engage Nav. If you wait, you will have intercept issues for sure as the computer does not home to a fix it generates a Bearing and flies it.  This is actually true to all aircraft. Wait to long and the computer won't computer the intercept heading.

C) Just pulling from experience. No aircraft should ever ever ever just wonder in circles without programming.  If coming up on a Route Disco the aircraft should just enter into HDG HOLD and keep trucking along.  If it's reached the end of it's path and it's turning in circles again, submit a ticket with the Sim, Route and what happened and what you saw.  I don't have the CDU software manual to confirm this one. But just pulling from my experience with other aircraft this shouldn't happen.