METAR / FMC

[Guest lieuwe]

hallo,during the climbe you pass different METARS.the FMC has the LNAV and VNAV active. When i fly in another METAR than the FMC change his levels during the climbe. What can i do to make an easy climbe until a have the cruising FL.Flying greetings,Lieuwe

[markadeane 272]

Hi Lieuwe,When you say you 'pass different METARS', what do you mean, different barometer readings? Or wind? Are you using active sky or any other weather generating add-ons?Once you climb through the transition level (normally 18,000 feet) you should set your altimeters to 'STD' (standard) on the Captains EICAS control panel. Any pressure variations will cause you to go up or down a bit but the Autopilot should look after that.If you can come back with more information we'll see what we can do to help you.

[Guest lieuwe]

I use active sky. For example you have at EHAM an METAR but also EHSB and more in the netherlands. So when i got a new METAR in active sky than the FMC change the FL and so the v/s.But you talk about TL and set your STD, in the Netherlands whe have an TL=045. So I will find out what will happend after i set the STD.For so far thanks for the info.

[ronzie 21]

Once at or above the transition altitude you just switch to the STD altimeter pressure. As you listen to AS Flightwatch giving you different surface pressures you just ignore them unledss you need to be aware of the surface pressure as an advisory on what to expect.If you are using FS ATC, which I do not use and may need to be corrected, I believe it only uses a TA/TL of 18,000 feet, the US standard. I use Radar Contact 4.01 which specifies the TL at departure and destination airports and also allows you to modify that. So far it has followed the info I have regarding this at US and none-US airports. The result is that with FS you use a TL of 18,000 so FS ATC thinks you are at your correct altitude. With RC4 you can write down the TAs before plan activation and it will also give you an aural indication (a voice says "altimeter check") when you should engage or disengage STD.Surface pressure comes into play again when you descend. ATC should tell you the altimeter setting they expect you to use below the transition altitude. You can dial this in prior to disengaging the STD button so you are prepared as you cross the boundary.Flightwatch may give you surface pressure in the area you are in which you can use as a guide to what to expect. ATIS should also be close. Anyway, if on ATC, you must use either STD or the surface pressure ATC states so in all cases all aircraft use the same altimeter settings for vertical seperation. The surface altimeter setting is for approach vertical seperation and to get you in proper vertical profile to avoid obstacles and enter the published approach vertical profile whether ILS or other means.Also be sure to get if you are using AS6 the just released SU3. It fixes a memory leak caused by ASG if enabled that caused FS crashes after some length of flight time. See their support forum here on AVSIM for the link.