I am finally a private pilot!!

[scottb613]

Hi Folks,

Now THAT's what I'm talking about - CONGRATS - and I'll leave you with my CFI's parting remark - "now remember - gas is better than brains"...

Regards,
Scott


Sent from my iPad using Tapatalk

[N324JK]

Congrats! Got mine not too long ago - amazing feeling, isn't it?

[griff4]

Would someone have the time to explain density altitude. First I've heard of it!!

[N324JK]

Would someone have the time to explain density altitude. First I've heard of it!!

I'll take a crack at it, but, full disclosure, I'm not a CFI; just a private pilot who geeks out over the physics involved in flight.

Density altitude is commonly defined as pressure altitude corrected for nonstandard temperature variations. At this point, if you're saying, "huh?", then we're on the right track.

If you remember physics at all, then you'll remember that the pressure, temperature, and volume of a gaseous mixture are all related. Volume, in turn, plays into density, in that density is a function of mass per unit of volume. In that sense, because there's a common relationship between temperature and density (i.e., volume), we can relate the two.

That was probably as clear as mud, but here's the bottom line: if we actually did the math for a given mass of air, at a given pressure, and all we did was increase the temperature, then we should see the density of that air go down. Conversely, if we decreased the temperature, we'd see the density go up.

Great, you say, but what does any of that have to do with altitude? I'm so glad you asked. It's all about performance. We know from experience that our airplanes perform better or worse as we climb or descend. Why is that? Because, as altitude increases, air density decreases, and vice versa. This affects engine performance and how much lift the wings can produce. As described above, we also know that, as temperature increases, air density decreases, and vice versa. So, when the air temperature goes up, we should expect the airplane will "act" like it's at a higher altitude, because the air density decreased. And there's a formula that we can use, based on the air temperature, to infer what altitude the plane will "act" like it's at, so we know what performance to expect. This inferred altitude is...wait for it... density altitude!

So now it's time to tied it all together to understand why we care about density altitude. Let's say it's a hot, sunny day in a place like Denver, where we're already about 5000 feet above sea level. Let's also say that we're at an airport with a relatively short runway, and the plane will be at maximum gross weight at takeoff. There's already a concern that our airplane will be at a lower performance because of the actual altitude (which represents a lower air density). On top of that, because it's hot out, we know that "hot" means lower air density, and would therefore cause our airplane to perform as though it's at an even higher altitude. So, we'd calculate density altitude to understand how our airplane will actually perform so that we'll know whether we can lift off the runway. Oh, by the way, there's at least one YouTube video out there of an example when somebody *didn't* respect density altitude, and it ended in some less-than-ideal results.

I hope that gives you the answer you need; if not, there are plenty of places on the internet that can provide more detail.

Enjoy, and happy flying!

[pilotman767]

Congrats! Look forward to hearing about your adventures in the big blue

I will keep you, and everyone else in the loop! I start my post-license flying on Monday

[Lewis - A2A]

Hope you had a great first flight

[pilotman767]

Didn't fly
Airplane went in for maintenance. No one knows why, but it should be ready for a flight tomorrow (Feb 29th).
Until then, I'll just put around in the A2A 172

[Piper_EEWL]

I've been there. Totally sucks if that happens but oh well. Oh and by the way if you want to go flying on February 29th you might have a problem again. Because I'm fairly certain it's March 1st

Happy flying

[seaniam81]

Congrats guys, and welcome to the club