random missions have altimeter errors

[cichlidfan]

I am sure this is mentioned somewhere but I could not find it.

 

I just started playing with random missions, haven't tried since I first got 0.6, and there seems to be an issue with the altimeter alignment/settings.

 

I create a mission with a runway start and I am at -300 ft on the runway. At a different airfield it was a different but still negative altitude.

 

I am suspecting that this may have something to do with changes made to ramp starts but I am still at a loss why a runway start does not have all avionics properly setup.

[GGTharos]

I suspect this may have something to do with the weather ...

[cichlidfan]

I suspect this may have something to do with the weather ...

 

Which would be something that would have been adjusted for prior to putting the plane on the runway.

[EtherealN]

Just turn the knob on the altimeter, that's what it's there for. :P

 

(I don't know what the SOP for A-10 pilots is, but when I fly IRL it's one of the last things I do before takeoff. That is: I do it on the runway.)

[cichlidfan]

Just turn the knob on the altimeter, that's what it's there for. :P

 

(I don't know what the SOP for A-10 pilots is, but when I fly IRL it's one of the last things I do before takeoff. That is: I do it on the runway.)

 

Would you adjust based on known altitiude or barometric pressure?

[EtherealN]

Based on the QNH reading given to me by the tower with the takeoff clearance. At least at my home field, I have flown from places that give QFE reading instead, and then I'll do a QFE setting instead.

 

I can cheat when at home, since I happen to know the elevation is 105 meters above sea level I can just adjust such that it reads 105, but it is always preferable to get a proper reading - if I adjust to that setting they give me and my altimeter reads something else than 105, I know I should abort the takeoff and get the altimeter serviced. (I have trained to fly without altimeter and could do it just fine, but that's mainly emergency procedure.)

 

QFE fields the same theory applies - could just set it to 0 and be happy, but if available an independent reading is always nice to have in order to verify proper altimeter function.

 

The risk of altimeters going wonky is of course very small, but hey... :P And in the case of DCS, long-term wear of components isn't modeled so you will know for sure that the altimeter does actually work.

[cichlidfan]

Based on the QNH reading given to me by the tower with the takeoff clearance.

 

There is the issue. When you do a runway start you do not have the option to request clearance for takeoff. It would have been done before you left the hold short area (according to the procedure in the FM) in theory.

 

If you do try to contact ATC the only option available is request startup. Granted, you can probably step through the ATC comms but that should not be required when all you really need is a weather report.

[EtherealN]

There is the issue. When you do a runway start you do not have the option to request clearance for takeoff. It would have been done before you left the hold short area (according to the procedure in the FM) in theory.

 

...but since the altimeter, by definintion, cannot be given to you in a broken state in DCS, just turn the knob either to give you zero elevation (QFE) or to give you your known ASL altitude (for that field).

 

Not saying everything is perfect, but the "fix" here is to spend 0.5 seconds turning a knob - a knob that you would have turned anyway during your takeoff preparations.

[cichlidfan]

I get your point. Yes, it is a simple thing to deal with.

 

The 'fix' is a bit more problematic if soemone were to create a random mission starting in the air though.;)

[GGTharos]

No, it really isn't ... just ask for landing permission from ATC. He'll give you a QFE.

[EtherealN]

If they're in the air they can source altitude information through the nav system which is already aligned and ready. ;)

[effte]

...and updated through GPS, with vertical dilution of precision insufficient for altimetry, even using the military P code. :)

 

(Barring carrier phase tracking, which I dont know if it is used by the A-10 or what accuracy it would give.)