VNAV ALT

[Gregg_Seipp 565]

 

 

I'm not here to boast or show off, I'm here to simply help with anyone who is passionate about flight simulation and aviation. The reason I made my channel is to share one way of operating this extremely accurate rendition of the aircraft and I love every minute of making content. Its's something, with some support from you guys, I will continue to do for the foreseeable future!

 

Love the videos you make!  Very detailed and thoroughly thought out.

[Guest]

 

 

Love the videos you make! Very detailed and thoroughly thought out.

Thanks a lot Gregg! Glad I could help.

 

Spoke to the engineers and 100% VNAV ALT is not fitted to our fleet.

 

 

Thanks for the feedback anyway! I will try and deactivate VNAV ALT by switching to the other MCP panel!

 

Fly Safe.

[Chock 17,769]

With PMDG is the only way to essentially "deselect" VNAV ALT to choose the Honeywell MCP? Certainly with all our new NG's with the Collins MCP there is no change to the logic of the system! Either way it's not going to be no scarbus!

 

 

Not sure. When talking about the real 737, I tend to go off what I've learned from this book:

 

http://www.b737.org.uk/book.htm

 

Which is worth getting, particularly if you drive the things for real, but also if you are a simmer with any 'study sim' version of a 737. Along with help from a couple of real world B737 pilots, I know I found that book invaluable when attempting to come across as authoratitive (yeah, right) when I was reviewing a 'proper' 737 sim aeroplane for Avsim, since in the real world, the fancy aeroplanes I fly are the ones which have a fully working radio lol (I'm not joking).

 

If I get time later today, I'll see what I can find in that book, although I should probably buy it again as my copy is a few years old and I daresay its been revised to remain completely up to date. Worth a look too, is the author's website:

 

http://www.b737.org.uk/

 

In any case, I always appreciate anyone's efforts to make tutorials. Being a software trainer myself (CGI, movie effects etc), I know how valuable the efforts of a decent teacher with some real world experience can be. So thanks for taking the trouble to pass on your knowledge.

[Spin737 102]

Sam,

 

Wait... hold on a second....

 

"I'm more familiar with the real thing then[sic] PMDG" and you don't know what/why/how VNAV ALT is?

 

mmmmmmmmmm.....  Okay.  Right.

 

Keep on with it then.  You will need to work quite a bit harder to impress this audience with credentials, however...

 

It's an option. I've flown both types.

 

Line pilots, instructors, and designated examiners at my current outfit with tens of thousands of hours in the plane would look at you cross-eyed if you mentioned VNAV ALT.

 

<cough cough>

[ALF1 15]

As long as we are at it Filch or FL Ch is same as LVL CHG or level change. I believe all MCPs have one of the two. Important thing is the function where descent is at idle power while maintaining MCP SPD. Thrust goes to ARM mode, meaning you can add power manually if you wish. In climbs MCP SPD is maintained at N1 power.

 

Now a question, what is this Thrust Ref ? I have Thrust Hold but is only used on takeoff. I have never flown the Honeywell MCP.

[Guest]

Had a play around this evening, switching to the Honeywell MCP and I still have VNAV ALT annunciate if the aircraft levels off at an intermediate altitude set in the MCP window. I'm use to ALT ACQ then ALT HLD or VNAV PTH.

 

It's a bit of a pain when flying circling approaches in the PMDG based on our SOP's. With our old school non VNAV ALT fitted fleet we descend using VNAV to the circling minima rounded up to the nearest 100ft which is set in the MCP panel. Approaching the cleared Altitude we get ALT ACQ then ALT HLD, we break left or right using HDG SEL and set the MISAP ALT whist the aircraft stays in ALT HLD at the circling minima.

 

At the moment I'm getting ALT ACQ, VNAV ALT and when I set the MISAP the aircraft continues to descend on the VNAV profile. A quick fix is to select ALT HOLD but would rather have the aircraft in PMDG do it for me (I'm lazy) and it's what I'm used to.

 

I guess I'll ask PMDG directly and see if it's all setup this way or if I can somehow disable VNAV ALT! 

[G550flyer 1,008]

Very interesting discussion. VNAV ALT is pretty standard across a lot of aircraft with VNAV capability.  VNAV ALT is a very simple and benign annunciation. It something that you should expect. As stated before, it's basically a simple annunciation to tell you that the plane is going to level off at a procedural altitude. Say for example you are at airport x and flying the dixie one departure.

 

Your clearance is the dixie one departure, climb and maintain 10,000ft. Let's say the dixie one departure has you level off at 3000ft for one mile after departure. In this case, if you flew the departure in LNAV/VNAV, you should expect see VNAV ALT if you have your MCP set to your cleared altitude. Now in my old school days without VNAV, we would set 3000ft in the MCP and then 10,000ft after the mile. Same thing if you are flying an arrival and given the "descend VIA" clearance. If you were cleared down to 2000ft and the arrival had some level offs on the way down, you would expect to see VNAV ALT at those specific altitudes while in LNAV/VNAV.

 

Now that's a basic description. It's similar to the jets I currently fly. In my aircraft, we get VASL, VALT and the constraint altitude below the VASL/VALT on the PFD. It works the same as the Boeings. If I have a constraint altitude on the way up or down in VNAV, I will get a VASL(VNAV altitude select) annunciation on the PFD with the altitude right below. The altitude will have a hashed symbol in front of it meaning it's armed. Over the altitude tape, I would have my MCP selected altitude annunciation. Once the airplane captures the VNAV constrain altitude, the VASL will switch to VALT(VNAV ALT) and the constraint altitude will turn blue.

 

So again, the annunciation is the airplanes way of telling you it will level off to an altitude other than what you have selected on the MCP. It's a good thing.

 

As for your circle issue, interesting. In the jets I fly, we don't set missed approach altitude on a circle until on the go. We leave the minima in the MCP and once we change the lateral mode to heading select, it cancels VNAV and holds the MCP altitude. The only issue is when you go missed, the pilot not flying gets busy. You have to get the flaps, reach over and set a lateral source and or lateral mode for the pilot flying, dial 180 in the speed window, set a heading if not following LNAV, set missed approach altitude and come back to the gear awaiting the gear up call. It's all done in a couple of seconds. In your case, I don't know why it descends if you have minima set in the MCP, altitude captured and you entered heading select. We operate a couple BBJs, let me see what our SOPs say for circling for our Boeing guys.

[Tabs 2,790]

Had a play around this evening, switching to the Honeywell MCP and I still have VNAV ALT annunciate if the aircraft levels off at an intermediate altitude set in the MCP window. I'm use to ALT ACQ then ALT HLD or VNAV PTH.

 

It's a bit of a pain when flying circling approaches in the PMDG based on our SOP's. With our old school non VNAV ALT fitted fleet we descend using VNAV to the circling minima rounded up to the nearest 100ft which is set in the MCP panel. Approaching the cleared Altitude we get ALT ACQ then ALT HLD, we break left or right using HDG SEL and set the MISAP ALT whist the aircraft stays in ALT HLD at the circling minima.

 

At the moment I'm getting ALT ACQ, VNAV ALT and when I set the MISAP the aircraft continues to descend on the VNAV profile. A quick fix is to select ALT HOLD but would rather have the aircraft in PMDG do it for me (I'm lazy) and it's what I'm used to.

 

I guess I'll ask PMDG directly and see if it's all setup this way or if I can somehow disable VNAV ALT! 

 

We do not have an option to disable VNAV ALT - not going to be a way to do it unless we add it in a future update. Can you say which airline you're with? I'm curious...

[G550flyer 1,008]

I looked at our BBJ SOPs. They are letting the altitude capture at the 100ft increment above MDA or selecting Altitude hold at MDA if the MDA is a odd number. They then set missed approach altitude and heading select. That should keep the aircraft from descending once you are in ALT HOLD.

[Guest]

We do not have an option to disable VNAV ALT - not going to be a way to do it unless we add it in a future update. Can you say which airline you're with? I'm curious...

 

Hi Ryan,

 

A very big one in with almost 400 737-800's (I'll send a PM)

 

None of them are fitted with VNAV ALT. Am I right in thinking you could deselect VNAV ALT with previous versions of NGX? If that could be reinstated that would be great! 

 

 

I looked at our BBJ SOPs. They are letting the altitude capture at the 100ft increment above MDA or selecting Altitude hold at MDA if the MDA is a odd number. They then set missed approach altitude and heading select. That should keep the aircraft from descending once you are in ALT HOLD.

 

Really interesting Rick thanks for sharing. We always round the MDA up to the nearest 100ft which we set as our minima and the MCP ALT. When ALT HLD annunciates we use HDG SEL, break L OR R and then set the MISAP so in a slightly different order to how your guys do it on the BBJ.

 

Then if we go around at any point we just have to push TO/GA and go from there, the MISAP is already set so the PM is just having to configure as he would on and go-around. Depending on the MISAP you can either use HDG SEL or LNAV once established on an intercept for the missed approach track. I'm not sure about the BBJ but usually in the -800 you have to hold F15 to comply with the 180kts which causes the warning horn to go off! 

 

Really nice to see how other operators manage it.

[ALF1 15]

In paragraph 1 above, are you still in VNAV mode ? I would imagine if circling you would already be out of VNAV. I dont fly a 737 or a Gulfstream so I dont know. I am just curious why the VNAV ALT annunciation is a nuissance while circling after minimums.

[naderhere 4]

Sam,

 

Wait... hold on a second....

 

"I'm more familiar with the real thing then[sic] PMDG" and you don't know what/why/how VNAV ALT is?

 

mmmmmmmmmm.....  Okay.  Right.

 

Keep on with it then.  You will need to work quite a bit harder to impress this audience with credentials, however...

 

Hi,

 

First time posting, but I tend to feel that I need to reply. Why are you so quick to let them know they're wrong? Seems a bit out of line to be rude right away and then later realize that he is just asking a legitimate question.

 

Thanks!

 

Nader Kanzu

[G550flyer 1,008]

I've posted this before, but a good little guide from our SOPs for operating. This is for our BBJs, but great info that guys can use.

 

Aircraft References

• Main Gear on your side: NESA Transmitter in lower outboard of window
• Main Gear on Opposite side: Lower inboard corner of window
• Outboard Side of Engine on your side: Window Handle
• Outboard Side of Engine on Opposite side: Glare Shield bend
• Wingtip on your side: 2.5 concrete blocks
• Nose Gear: Inside of HSI

 

Engine Start (Approximate values)

• 2 -- 20% N1

• 4 -- 400 degrees EGT

• 6 -- 60% N2

• 6 -- 600 pph FF

Before Takeoff (LLLAASSTT Chance)

• L-anding Lights (tech: nose wheel light on when cleared for takeoff)
• L-adies (sit the FAs down with PA message to the back)
• L-ower DU display cleared
• A-utothrottle ARM (tech: when cleared for takeoff)
• A-utobrakes - RTO
• S-trobe lights ON
• T-errain (tech: Captain Terrain/FO Weather)
• T-CAS (TA/RA)

10,000’ check during climb out (FLAAPS)

• F-uel Pumps (Ctr Tank management per alternate operating procedures)
• L-anding Lights -- RETRACTED/OFF (consider 18,000’ in high- traffic

areas)

• A-irspeed -- accelerate to desired climb speed
• A-PU -- Off/as desired for shorter flights/EROPS/WX
• P-ressurization check (Auto/pressurizing/cabin alt OK)
• S-eatbelt (double ding by going off/wait 1 sec/on then auto)

Before Descent (AIRBAG)

• A-TIS
• I-nstall the Approach
• R-adio’s -- Tune and ID
• B-rief the Approach
• A-pproach Checklist
• G-o Around Procedures (How will the airplane fly it? HDG SEL, etc.)

Planned Descent Point

• Timing -- Approx. 10 seconds for every 100’ of altitude to lose
• Distance -- Divide HAT by 300’. This is the distance to start descent from the end of the runway.

 

Enroute Descent Path Planning

• Build a waypoint 40 NM track distance from the landing runway with 240/10000 inserted for Speed/Altitude. - AND/OR - Use the fix page and put a 40 NM circle around the runway (or FAF) and plan to cross the circle at 240/10000 for a straight-in arrival.
• When planning an enroute descent to radar vectors to final it can be difficult to determine how far out you will be vectored and how soon you should begin your descent. Request a descent at a distance that will allow a constant 1500 fpm descent. To determine this descent point:
• Load the expected approach using the FMS DEP/ARR page
• Load the FAF or OM point/altitude on the descent page at 3R.
• You can monitor the V/S as you approach this point. When the V/S approaches 1500 request descent. Even if the descent is not granted immediately, you will have a very good target descent rate when ATC permits the descent. This technique provides a constant descent that mirrors our constant climb to cruise profile.

Descent Profile

• 3.5:1 (Miles : Altitude)
• For every 50 Kts of wind +/- 2 Miles
• Losing 10 KIAS Takes 1 NM

 

10,000’ check during descent (10,000’ AGL for higher field elevations) (FLAAPS)

• F-uel Pumps (Ctr Tank management per alternate operating procedures)
• L-anding Lights -- EXTENDED/ON (consider 18,000’ in high-traffic areas)
• A-irspeed -- decelerate to 250
• A-PU -- On/as desired/WX considerations
• P-ressurization -- set for landing field elevation
• S-eatbelt (double ding by going on/off/wait 1 sec/on)

Cat II/III ILS (ABCD)

• A-PU -- On
• B-rake Setting
• C-at II/III ILS Procedures
• A -- Approach Brief
• A -- Alert/Decision height callouts
• A -- Altimeter bugs (radio and barometric)
• D-epart runway plan (How will you taxi to park -- SMGCS?)

Before Every Approach

• “AAABBCC”
• A-TIS
• A-pproach loaded in FMS
• A-irspeed set in FMS
• B-rief
• B-rake setting (off, 1/2/3/Max)
• C-hecklist
• C-onfiguration (flap setting)

• “CRAMPS”
• C-ourses -- set/verify inbound course on MCP for FP & PM
• R-adios -- set/verify correct frequency (ILS/VOR/Tacan/NDB)
• A-ltimeters -- set/verify QNH/QFE as appropriate through transition
• M-inimums -- set/verify for PF & PM
• P-ush -- APP mode (or VOR/LOC or LNAV or Hdg Sel)
• S-peeds -- set/verify Vref is set and displayed for flap setting

Engine Failure on Takeoff

• “4 Cs” (accomplished when flaps are up at min. maneuvering speed)
• C-hange (Level Change)
• C-ontinuous (Max Cont)
• C-rossfeed (with fuel only in wing tanks)
• C-hecklist (NNP then After Takeoff)

Single Engine Trim

• Trim into good engine is approximately equal to Fuel Flow

Single Engine ILS Approach

• At 1.5 Dots or later on the Glide Slope --
• Gear Down
• Flaps 15
• Reduce Thrust 10% N1

Non-ILS Approach (VNAV is preferred for straight-in approaches)

• 3 NM -- Configure (Gear Down/Flaps 15, Bug 15, Landing checklist to flaps)
• 2 NM -- or sooner/Set Next Lower Altitude (ensure VNAV if using)
• 1 NM -- Flaps 30, Bug 30, complete Landing checklist
• 0.2 NM -- V/S As Desired (unless using VNAV)

Touch and go/pattern work Missed Approach

Note: Assumes intent for complete flap retraction to missed approach holding

pattern.

• TO/GA (A/P will kick off under single-channel operation)
• Set Go-around thrust
• Set pitch to Go-around attitude
• “Flaps 15”
• Positive climb rate - “Gear up”
• 400’ AGL - “LNAV” or “HDG SEL” (Note: for Non-Precision approaches your probably already at/above 400’ AGL or very close if going missed from and DA/DDA/MDA)
• Retract flaps on speed
• 1000’ AGL - Set LVL/CHG or V/S + 1500’
• After Takeoff checklist (Ops Man)

Radar Pattern Climb Out From Touch & Go

• PF rotates aircraft to 15 degrees nose high
• Positive climb rate - “Gear up”
• Flight directors - ON (if coming from VFR Pattern OR Recycle)
• 400’ AGL- “Bug Up, flaps 5, LNAV or HDG SEL ”
• 1000’ AGL - Technique: "V/S, Set 1500 fpm" or "LVL CHG"
• Retract flaps on schedule to “Flaps Up”
• After Takeoff checklist
• Maintain flaps Up for downwind

Note: PF re-establishes A/P and manually arms Autothrottles

• PM rechecks weather, installs approach and helps tune nav radios (technique)
• PF briefs approach, tunes radios and calls for the “Approach check”

Precision Approach (use “CRAMPS” check technique)

• Arm APP if cleared approach on intercept heading (FOM/technique)
• G/S alive - “Gear down, flaps 15, Bug 15, landing checklist to flaps"
• G/S intercept - “Flaps 30/40 (final flap), Landing checklist” slow to VREF + additive

Non-precision approach (non/VNAV)

• Arm LNAV or use HDG SEL for lateral maneuvering
• 3 miles prior - “Gear down, flaps 15, Bug 15, landing checklist to flaps”
• 2 miles prior (or earlier) - Set MDA or stepdown altitude in altitude alert window
• 1 mile prior - “Flaps 30/40 (final flap), complete Landing checklist” slow to Vref + additive

Note: Do not arm speedbrakes or use autobrakes if accomplishing a touch & go.

 

VFR Pattern Climb Out From Touch & Go

• PF rotates aircraft to 15 degrees nose high
• Positive climb - “Gear up”
• Turn off FDs if not already off (technique)
• 400’ AGL - “Bug 5, flaps 5” (technique)
• 1000’ AGL - PF lowers nose to 10 degrees pitch and reduces thrust (at Bug 5 speed) to approximately 75% N1 (technique)
• PF levels off aircraft at 1500’ AGL or pattern altitude and maintains flaps 5 on downwind

VFR Pattern

• Enter downwind at flaps 5, speed Vref 30 + 40 (Bug 5 speed)
• VFR pattern briefing - "30/40 Flap touch and go, Speed is          "
• Approaching abeam touchdown point - “Gear down, flaps 15, bug 15 Landing checklist to flaps” slow to Bug 15
• Before turning or during turn to base - “Flaps 30/40, Bug 30/40 +          (additive), complete Landing checklist,” slow to Vref + additive
• Descend as required (approximately 600-800 VSI as a guide) Note: Do not arm speedbrakes or use autobrakes if accomplishing a touch & go.

Technique for Establishing Automation After Pattern Work

Note: Technique used should be pre-briefed. Assumes the "gear up" and "flight

director’s - ON " is already called/done.

• 400’ AGL "Bug Up, Flaps 5; HDG SEL or LNAV"
• 1000’ AGL (or A/R) "Vert Speed + 1500’, Flaps 1" or "Level Change" (Flaps 1 above F5 speed and then flaps on schedule)
• PF establishes A/P by selecting CMD and A/Ts -- ARM

[Guest]

In paragraph 1 above, are you still in VNAV mode ? I would imagine if circling you would already be out of VNAV. I dont fly a 737 or a Gulfstream so I dont know. I am just curious why the VNAV ALT annunciation is a nuissance while circling after minimums.

 

Hi Alberto, the descent from the platform altitude to the circling minima is flown using VNAV PTH (we open the SPD window a couple of miles before the Final Approach Fix but with the speed window open the aircraft stays in VNAV PTH because the Flaps are extended) 

 

Approaching the circling minima our aircraft (Non-VNAV ALT) pitch FMA transitions from ALT ACQ then ALT HLD and we fly the visual segment of the circling minima in ALT HLD maintaining the circling minima rounded up to the nearest 100ft. We use HDG SEL for the lateral profile and we have our own specific SOP's for timings and TRK's to be flown. Once established on base/final we disconnect and fly manually.

 

 

 

 

F-uel Pumps (Ctr Tank management per alternate operating procedures)

L-anding Lights -- EXTENDED/ON (consider 18,000’ in high-traffic areas)

A-irspeed -- decelerate to 250

A-PU -- On/as desired/WX considerations

P-ressurization -- set for landing field elevation

S-eatbelt (double ding by going on/off/wait 1 sec/on)

 

 

Interesting to see Rick, some very similar to my operation and others completely different! FLAAPS I think is really common for a lot of 737 operators in Europe passing FL100 (10,000ft for you guys the other side of the pond!!)

[Turlad 0]

Had a play around this evening, switching to the Honeywell MCP and I still have VNAV ALT annunciate if the aircraft levels off at an intermediate altitude set in the MCP window. I'm use to ALT ACQ then ALT HLD or VNAV PTH.

 

It's a bit of a pain when flying circling approaches in the PMDG based on our SOP's. With our old school non VNAV ALT fitted fleet we descend using VNAV to the circling minima rounded up to the nearest 100ft which is set in the MCP panel. Approaching the cleared Altitude we get ALT ACQ then ALT HLD, we break left or right using HDG SEL and set the MISAP ALT whist the aircraft stays in ALT HLD at the circling minima.

 

At the moment I'm getting ALT ACQ, VNAV ALT and when I set the MISAP the aircraft continues to descend on the VNAV profile. A quick fix is to select ALT HOLD but would rather have the aircraft in PMDG do it for me (I'm lazy) and it's what I'm used to.

 

I guess I'll ask PMDG directly and see if it's all setup this way or if I can somehow disable VNAV ALT! 

 

flightdeck2sim,

 

I'm an FO at your airline (at least I'm 99% sure it's the same outfit...). I find there's a couple of things in the PMDG NG that aren't quite the same as our fleet. VNAV ALT is indeed an option we don't have and curiously PMDG did actually model it as an option in their older FS9 original 737. 

 

VNAV will descend below the MCP alt in the NGX for some reason. I find the best way to practice the circle is to wait until after 4nm Gear down / F15 with VNAV path stable with a constant V/S.... Then actually engage V/S mode(!) and just monitor the vertical speed, try to stay on path. ALT HOLD will engage at 900' (you are doing RW16 circle  34 right........hehe) and you're good. I find it's still a bit lazy with the alt capture though so sometimes I add a hundred feet or to the minimums, just to get the correct height above ground downwind. I guess it's just a 'simism' workaround that makes the numbers work a little better.

 

Adam