Marenostrum

I want to publicly thank Fs2crew: one month ago I bought an Fs2crew product forgetting to request a discount granted to the members of my VA Flyuk. It was my fault, obviously.

Today I have realized it and wrote an email to ask a credit for future purchases. 

After only few hours I got a short and clear answer: they have recognized the credit.

It could sound normal to many people and, eventually it is. But in the jungle of all the possible answers and excuses, I have really appreciated this simple and fast YES.

So...I want all simmers to know about the commercial correctness demonstrated by F2crew.

my regards

Stefano

19 minutes ago, downscc said:

Wow a double loop... I've often seen the ND render such nonsense only to have it correct itself after takeoff.  Of course I'm ready to take control if LNAV is going to wander off clearance but it usually works out.  There are rare occasions where Navigraph gets something coded wrong but it is pretty rare.

Just one more reason we need PMDG to build a new  FMC for the entire product line that uses ARINC navdata instead of the obsolete macro language that's been around since the 90s.

That's means that in the real world such a thing never happens..right?!

by the way, my acceleration altitude setting, vspeeds, trim, winds, ...were already set as usual. I have tried also to change the initial climb setting...but I always got the picture shown.

It is like the FMC was calculating "its" way to pass at 700ft and above 1700ft  to respect the altitude restrictions within the SID: in this case the runway is quite long and I took off pretty soon and I was able to manually flying passing at the two restrictions without problems...but if the FMC calculates the distance between the rwy and the first wpt from the end of the rwy, in that case, to be at 700ft would have required a steep angle and, for this reason, the FMC has calculated the 360 turn.

is this  a possible reason?

Taking off from EBBR 25R SID DENUT 6C the route requires a 3.8% up to 700, then 7.0% up to 3200 to minimize noise disturbance. There are two altitude restrictions: at 700 and above 1700 following the sid to DENUT

What to say....

I have more than understood!

Thank you Alan for your complete answer.

I am at the gate. Sometimes I see the OVERWING DOORS light up (but they are closed).

It is an alert for a non perfectly not closed door....I try to reopen and close...but the lights are still on.

The QRH says: if pressurization is normal--> continue

if press is not not normal --> plan to land

Obviously it refers to an inflight situation.

But what to do when I am at the gate?...in rw I suppose you have to call maintenance to check it

(btw I took off monitoring the light and it switched off after about a couple of minutes)

What to do in these cases (as I imagine that taking off it is not the correct procedure !)

Thank you!

15 hours ago, Spin737 said:

VNAV does not change climb rate. It only commands an airspeed at CLB, CLB-1 or CLB-2. It will level you at the lower of any LEGS restrictions or the MCP.

It's possible I'm missing some option, but in my experience, it's basically full thrust until you get to the next restriction.

I tested it (same aircraft, same fuel, same payload, same climb setting CLB-01, same derate TO-1, same flaps, same wind conditions)

I did a first climb path following the FMC route to go from rwy 05 @EGCC to the first wpt KOXUM. VNAV and LNAV engaged.

I did a second climb path following the vectors by ATC, that is proceeding straight ahead without turning immediately and, after about 3 miles, doing a first turn 90° left and after about 2 min another turn left inbound to KOXUM. So a longer course.. HDG SEL and VNAV engaged

Both path ending at 9800 ft

The table above (for each position there is a picture if you like to see it) shows that I reached 9800 ft after about the same time but at a very different position.In few words (as stated by Dan and Matt) VNAV does not seem to control directy ROC. It simply follows the chosen CLB program and climbs up to the MCP altitude.

55 minutes ago, killthespam said:

King of tough to explain but something to take in consideration in a short explanation without getting involved into much details.

VNAV will be active and compute a climb/descend within 20 NM left/right of magenta line (adjusting constantly to stay on PATH or fulfill crossing restrictions adjusting ROC/ROD).

And for that reason, yes there is a relationship with LNAV based on this criteria. 

Outside of 20 NM L/R of course (magenta line) cannot compute a PATH, will just go on SPEED.

It's very difficult to understand what actually is doing without proper reading and training, and quite impossible to explain in a few words.

I was replying to downscc and, as soon as I have posted I have seen your answer.
I think that your post answers my question.

If the course is within 20 NM from the magenta line, the VNAV function does calculate the adjusted ROC.

Now it is interesting to know (and I can test it) what does it  happen if I do an off-course turn left (following the example) that makes the distance between the two waypoints in the FMC shorter. the VNAV should ask for a steeper ROC...because it will read the sequence of points in the route, faster than the planned route... and the adjusted ROC will steeper than the planned one.

Is there a limit after that the VNAV gives an alert and eventually disengages because a too steep ROC?

1 hour ago, downscc said:

I may not understand the question but I will try.  The VNAV does not computer off-route climbs or descents.  It will adjust once you return to LNAV/VNAV modes and execute the direct or new route.

mmhhh. if it so...I wonder why the B738 flew in the way I described: when I was off-course compared to FMC route (following the ATC instructions) with the VNAV engaged, the aircraft continued to climb (I had no alert messages in the FMC) but simply I was climbing at a very small rate of climb.
As soon as I narrowed my off-course route approaching the planned FMC route the rate of climb increased.

For this reason I have supposed that the VNAV (I repeat, engaged) was trying to follow its vertical planned path, but because it was off-course (for a wider turn than the planned one),  it was reading the approaching of the subsequent interpolated points of the route (between the two waypoints I was flying), at a lower speed...and consequently it calculated a smaller rate of climb. As soon as I narrowed the real course respect the FMC course, the computer was reading the sequence of points from the first to the second waypoint coming fastly...and the ROC increased.

But this is only my "dislexis" reading of the computer calculation. 

Thank you!

But what if my real route is shorter...does VNAV compute a steeper  climb?...is there a limit and a consequent error that I could receive in my FMC?

(the LNAV at the end of my post was a mistake..I was intended to write VNAV as you say)

To ask the question I write what I did then I ask the question (be patience with me I cannot find a shorter clear way to explain it!).

1. I am cleared to Take off from EGCC rwy 05L.

2. My first wpt is on the other direction (230° toward KUXEM).

3. No SID here, ATC will give me vectors: after the take off I am expecting a left turn 90° and a little later another turn 90° left direct to KOXUM. (so not a 180° continuous left turn).

4. my NAV display shows the same but with a small difference: the left  turn is quite immediately, continuous for 180° directing to KOXUM. 

5. I plan to take off with  only the HDG SEL armed on the autopilot. 

6. After the take off I climb straight ahead heading 053. Once at 800 ft I engage the autopilot with the HDG SEL active, proceeding 053 and I engage the VNAV too (so HDG + VNAV but LNAV is off).

7. I see on my NAV display that I am flying 053 whilst the FMC planned route was telling me that the 180° left turn was before my actual position: Now my real course and the planned FMC course are diverging  because I am following the ATC instructions.

8. when I am about 3 miles after the planned turning point in the NAV display, ATC gives me the first 90° left turn heading 330°. I do it. Now I am about 3 miles out of my planned course.

9. Now I am heading 330°  whilst the FMC planned course wanted me to direct to KUXEM heading 230° so I am still diverging some miles out of  the FMC route.

10. Now ATC tells me to turn left 230° to resume my planned navigation (to KUXEM).

11. At this stage I turn a little more left than 230 directing to KUXEM and, mile after mile, I am narrowing  my real route with the FMC route on the NAV display. The divergence of some miles becomes less and less until KUXEM where it becomes zero and I engage LNAV on the autopilot.

Now the question.
As soon as my real course and the FMC course were diverging, I noticed that my climbing angle was less and less.....once I turned in the direction to KOXUM narrowing the difference between my real course and the FMC course the climbing angle increased (at least  so it seemed ).
Is this happening because the FMC is calculating that the vertical navigation points (real and planned) are diverging so it slows down the climb (because my real course was longer that the FMC course) and once I was narrowing the planned course the FMC understood my increasing gradient of narrowing and then increased my rate of climb?

in other words: how the LNAV computes my vertical navigation path if I force my aircraft not to follow the planned course?

And what if it was the contrary: real route shorter than planned FMC route...have  I to expect a steeper climb ordered by the VNAV function? 

Is it allowed?

Thank you for your patience before than your answer!

2 hours ago, downscc said:

very sharp people, very dedicated. 

.... people running real risks...I have read an interesting report by NTSB about an almost crash during the a survey mission inside a hurricane!!

2 hours ago, Stearmandriver said:

 

OK, sorry, I'll reign in the weather geekery. 

Nulla di cui dispiacersi.....l'rgomento è molto interessante, forse molto noto  a molti piloti ma certamente non inutile da rinfrescare.

Avevo letto e visto anche alcuni documentari sui fulmini "verso l'alto" visibili dallo spazio. 
Molto interessante, spaventoso e affascite
Neanche io vorrei essere su un U2 o un SR71 per verificare la loro pericolosità!

1 hour ago, downscc said:

You cannot tell if a storm has or will spawn a tornado by looking at it in the air from an airplane.  Tornadoes do seem to come from a storm system that has multiple embedded CB but it's not true that such a system is required for or will always spawn tornadoes.

Interesting...

In any case from the pilot point of view, the key point is if these types of cells can be flown over their top or if they are the kind of monster that climb up to over FL350 ... so you can just stay away and fly around.

19 minutes ago, Stearmandriver said:

Some extreme examples on this image search :

The pictures attached are very scary!!!! I For sure it is not necessary to browse the SOP to stay away from them more than 50nm. 

Some of them in the pictures are also very wide, tall and, if it is not enough, twisted ...to fly around such a large beast it could be a long way.

I suppose that inside them you find a mix of all the scary situations: high speed wind variation with rapid variation in direction, ascending and descending currents, hail, heavy rain...
I have read that they can build inside also vertical windshear  at high altitude rotating updraft!! (I knew about the descending windshear at low altitude dangerous in the approach phase, not vertical windshear dangerous at a cruising FL).

If I were a pilot facing a beast like that...I would like to be in a sim!

14 hours ago, skelsey said:

Yup... and that's why you checked the SigWx and other weather charts for your route beforehand and added some extra fuel, right? 😋

Sure 🙂

15 hours ago, downscc said:

This is routine during the spring/summer storm season in the US.  For example, I'm just down the coast 200 nm from Houston and there have been days when I went North of College Station to get there, adding at least 100 nm to a 200 nm trip.

I see you are used to fly in a zone that is also hit by twisters..is it?

How are those cells seen by the cruising altitude?

What SigWx says and what to do?

Very interesting topic here,

thank you for your explanations: this is an area where the simulation is unable to be like the reals world.

Only few days ago I was flying on a real 737 NGX of Ryanair from the north of Italy to Sicily....the sky was an amazing picture...with a lot of CB. They where far from us and similar to what the simulator with AS16 and REX soft clouds depicts ...but what the simulator cannot simulate is how they are dangerous.

4 hours ago, Stearmandriver said:

 Most air carrier SOP is to avoid strong echoes by at least 20nm. 

I did some calculation...in the situation that I described it meant do deviate the course toward the upwind side of the right cell, then to fly around it staying at least 20NM away then to reconnect the original flight path.....in other words to extend the flight path of about 100 NM or more !!!!

Clear!

11 minutes ago, downscc said:

so while you will get away with brushing aside a towering CB in the simulator, you would not chose to do that real world.  That was the only point I was making with my hangar story.

Sorry for my lack in understanding (english is not my mother language) ..when you say the in the real world you would fly differently you mean that you would stay far away from such a situation without flying in the middle of the two CB?

To downscc

Thank you for your reply (I will check my sliders). I am sorry that I did not take a picture of the radar image ( I will do next time) but I can say that:

- what it was visible in the air was what I expected to see in the radar image: two clear cumulonimbus that from their base arrived at an altitude higher than my FL370. In this sense it seems that AS16 depicts the sky quite well (compared to the radar image in this and other situations)
- both similar, with the radar image showing them thick and round with a clear strong precipitation in the middle. The highest level of precipitation in the core was very wide and large like almost all the perturbation, so I expected a very strong gradient that was telling me...STAY AWAY
- the shape was almost round and not depicting an irregular  shape with the risk of a shadow situation (neither the radar image showed this risk).

From what you say it seems that your friend falled in a shadowed cell (scary!!) bt I do not know if the weather radar of the Citation has the same features of the NGX, neither I know if the NGX radar is in reality so clever to find potential shadowed cells! I know it is the same (with some modifications) of the Airbus A320.

To Stearmandriver

all you say makes sense to me: to summarize
stage 1: try to slow down (I assume slowing down with the autotrhottle intervention) to a speed .76 - .77 BEFORE THE POTENTIALLY DANGEROUS ZONE
stage 2: if not enough....disconnect autotrh. and  retard the throttles to no lower than about midrange
stage 3: third stage....deploy the speed brake

What I worry (at FL370) is exactly the small speed window between overspeed and the stick shaker intervention speed.

In this sense, if I have "clear sky space" to reduce my FL due to the "verticality" of the two perturbations, could it be a solution also to reduce my FL, should we say from FL370 to FL340?

Is there a specific SOP addicted by each airline or are they general rules valid for all?

Really thank you to satisfy my immense curiosity!

Thank you...I will check it.

The AS16 turbulence factor has been moved many times (back) , expecially for the extreme sensitivity with the Majestic Q400 aircraft but The PMDG737 seems to behave better...anyway, have you any suggested sliders setting for AS16 on P3D 3.4?

Thank you

Imagine this scenario:

I am cruising at FL370

The weather radar is showing some cumulonibus along my route.
They are on the right and on the left.
With a small deviation I am able to fly in the middle without crossing neither of them but the separation is about 10 mils so I expect turbulengce also in the clear sky in the middle of the two.
I fly and suddendly I enter in a not to heavy turbulence but the airpeed starts  to fluctuate and to enter in the overspeed zone.
What to do?
How to properly manage the airpeed in these conditions?
Can I allow the aircraft to violate the overspeed zone for some seconds whilst the autothrottle is slowing down to recover the situation?
Or have I to anticipate slowing down before entering in the supposed critical zone?
If I have to slow down...at what speed?

Thank you to all real pilot in advance!!!

1 hour ago, JoeDiamond said:

No turn is short enough that you would need to do a fast alignment.  You are better off just doing a full alignment every flight.

I thought it was not so critical considering that, from my knowledge, the IRS     is the last system in term of priority that the FMC uses to define the aircraft position after GPS, 2 or more DME stations, 1 VOR-DME, 1 LOC-DME, 1 LOC and finally the IRS.

Nontheless in a "desert" area it could remains the unique alternative to the GPSsystem.

thank you

2 hours ago, MarkJHarris said:

Yep. Except in a certain batch of airplanes produced from 2016-2017, where you shouldn't realign IRU,up to an 18hr limit, its a fast or full re-alignment each flight.

Just turn the switches back to off, then NAV. Enter the airport I.D. and then go to page 2 to copy the GPS co-ordinates into the scratch pad, then back to page one and enter them.

Thank you Mark,

This is what I usually do, but it takes time to realign. The fast alignement (that I did not use before) as Paul says, if I am not wrong requires to turn the switch to ALIGN (and not off) wait for the light ALIGN illuminate steadily and then it is possible to set the new position in the CDU. Then IRS mode selector back to NAV. This should be faster.

I wonder if the fast procedure is admitted only for a "small" realignment during a turn around (not a cold and dark start).

Thank you.