flight planning & altitudes

[petermortelmans]

Hi,

A couple of questions regarding flight planning:

1. How do you choose between the various planning options, more particularly between “VOR to VOR” and “low altitude airways”. Can you just select the shorter one, or are there any rules? Can you just add and delete waypoints to make a plan of your one that is neither VOR to VOR or low altitude airways, or will such a flight plan be refused by ATC, if you want to fly it online (or in real life)? Why do these airways exist, if you're allowed to deviate from them?

2. How do you determine your cruising altitude? I assume higher is better for fuel consumption, but sometimes lower is better for sightseeing, e.g. when flying IFR in VMC. The built-in flightplanner doesn’t let you choose your cruising altitude, and it doesn’t seem to take the selected altitude when loading a flightplan that was generated in flightsim commander, because the (built-in) ATC always sends me to a higher altitude than the altitude I want to fly. I haven’t flown online yet, so I don’t know what those ATC would do.

Thanks.

[lnuss]

1. If you are VFR, then use VOR to VOR, GPS or airways -- your choice. They'll accept your flight plan just fine. If you are IFR, ATC may (in real life) wish you to use the airways, though in FS you can probably do as you wish.

Before the advent of GPS and other aRea NAVigation (RNAV) devices, ATC nearly always required IFR filing via the airways, since those provide the required minimum ground clearance and guaranteed reception (when you use the appropriate published altitudes for the airways (MEA, MOCA and MRA), and it enabled easy communication of intended flight path and other nav info between the pilot and ATC. Today they'll often (not always) let you go direct, if you're not in congested airspace, such as the east coast corridors, if you've got IFR approved GPS.

In either case (long ago or now), VFR flight plans were (and are) your choice of routes, since a VFR flight plan (in the U.S. -- some other countries are different) is not much more than a way to get a search started if you're overdue.

2. If you're VFR, you can pretty much choose what altitude works best for you, and change it from time to time (without having to change your flight plan) as you wish, dropping from high cruise to very low, so long as you don't bust the required 1,000 above congested areas and 500 feet above lighter population (again, in the U.S.). So if you're going very far, you can go high for better fuel consumption, though winds and turbulence may change your mind on occasion, then drop low when you want to sightsee, then climb again (though the climb burns a lot of extra fuel, when you're doing it repeatedly).

If you're IFR, you'll need to stay at or above MEA (Minimum Enroute Altitude) when on the airways, and to do some careful computation and research for minimum safe altitudes when going direct, IF ATC approves a course other than the airways.

Note that IFR in VMC is almost meaningless from an ATC standpoint, since they MUST assume that you could be in IMC at any time, so that's what they'll approve. For the sightseeing, you'd probably have to cancel IFR to get low.

All the above applies in the real world in the U.S. Other countries sometimes have different rules, especially when VFR. In FS, "ATC" is often much more lax, and will often "approve" a plan that would not be approved in the real world.

[toosmall]

Flightsim's built in flight planner is capable of several methods of flight planning including the setting of the altitude.

Point to remember:

Flying generally East to West = EVEN altitudes
Flying generally West to East = ODD altitudes
VFR = As above plus 500' (ie E to W 4,000' plus 500' = 4,500' - W to E 3,000' plus 500' = 3,500')

If you intend to sightsee then suggest you file a plan VFR at no more than 4,500' and VOR to VOR

IFR up to 18,000' Choose low level airways
IFR above 18,000' Choose High Level airways

This is very basic but generally match real world filing so practice and when you can control your aircraft well enjoy flying on-line, file a flight plan stating you are a beginner and let ATC make any alterations as necessary and learn with each flight.

[loki]

Up here in Canada you can do the VOR to VOR thing, though it will only work along the southern portion of the country. The further north you go, the fewer VORs there are and the farther apart they get, to the point that you won't be in range of any at all. Almost every airport has, or had at least, an NDB beacon as they were a little cheaper and some had much greater range than VORs. Until GPS units became widespread, it wasn't uncommon to have American aircraft getting lost around here because they weren't familiar with NDBs. ;)

Something you don't need to worry about in FS that you do in the real world is hypoxia. Unless you have an oxygen system on board or the plane is pressurized, light aircraft are limited to 10,000' or below.

[toosmall]

Perhaps one of the reasons for discarding all the "standard" flight aids and moving to GPS flight planning which should make things easier and, hopefully, safer for all concerned.

GPS linked to TCAS should just about do it and with the newer Garmin glass cockpits now being seen in many GA aircraft it does mean it will be quicker.

Thanks for the 10,000' info. :)

[loki]

After reading my post again, I should have said all aircraft are limited to 10,000' unless they are pressurized or have an oxygen system. Makes flying through mountains a little more interesting. :)

[lnuss]

Something you don't need to worry about in FS that you do in the real world is hypoxia. Unless you have an oxygen system on board or the plane is pressurized, light aircraft are limited to 10,000' or below.

In the U.S. oxygen is recommended above 10,000 (over 5,000 at night), but is not required until you are either over 12,500 for at least 30 minutes or until you are over 14,000 feet. That's good for those of us who live above 5,000 feet, else we might need to have oxygen on board aircraft that rarely are so equipped, if we go anywhere near the mountains, even for a very short time. Still, if you're a sea level type, it's good to have it above 10K, and it's still good for us high altitude types to meet the regs (even if there were no enforcement worries).

[loki]

Interesting. Up here you must have oxygen for all crew members for anything over 30 minutes above 10,000'. Then again we don't have many airports that would be severely limited by this, even in the mountains.

[xxmikexx]

Don't do this at home, folks ...

I was a heavy smoker, and a sea level resident, while I was a new PPL. Just for the heck of it I took a PA-40 Cherokee up to sixteen thousand feet. In very short order I was seeing stars, and even though I commenced a rapid descent immediately I feel that I am lucky to be alive.

It is better to have and use oxygen but not need it than the other way 'round. Hypoxia can set in without your noticing it.

[skylab]

Just for the heck of it I took a PA-40 Cherokee up to sixteen thousand feet.

You were lucky to get that Cherokee to 16T. It took me half a day to get a Tri-Pacer to 12!

[xxmikexx]

skylab,

It was maxed out. It wouldn't climb any higher. And I was a fool to stay up there till it hit the ceiling. I told you my headwork was super-bad :), which was why I stopped flying.

[tigisfat]

Don't do this at home, folks ...

I was a heavy smoker, and a sea level resident, while I was a new PPL. Just for the heck of it I took a PA-40 Cherokee up to sixteen thousand feet. In very short order I was seeing stars, and even though I commenced a rapid descent immediately I feel that I am lucky to be alive.

It is better to have and use oxygen but not need it than the other way 'round. Hypoxia can set in without your noticing it.

here's another pearl from my vast collection of "I did something stupid" stories. I was up at about 10,000 in a warrior, and I lit a cigarette up. It was like Heroine. I got about as high as you can get in under a minute. For that first minute, I was sooooooooo happy. I kept thinking to myself how lucky I was to be taking the perfect flight on the perfect day in the perfect airplane, and wasn't everything as beautiful as I've ever seen it? What followed was the horror of wondering how I'd control an aircraft with seemingly limited consciousness. Instead of heading straight in and landing, I cancelled my IFR flight plan and hung around our local practice area for 30 minutes. I waited at 5,000 feet until I was positive I could safely land and the noticed symptoms had been gone for quite a while.