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kdarling

macrumors P6
That explains my bumpy landings when I'm doing IFR.

True, when you come down to runway height on the dialed-in altimeter, you're still five feet in the air. Obviously any subsequent drop to the ground, after you close your eyes and cut the throttle, is not your fault ;)

Explain me why you would be relying on the iPhone for altitude reading instead of the aircraft instrumentation?

Explain to me where I talked about iPhones. Please look up the word "segue".
 

motulist

macrumors 601
Dec 2, 2003
4,235
611
Now if we could only get an administration in Washington that has a clue about space technology. It has been at least 15 years since we have had a rational plan for space coming out of washington. Really pathetic when you think about it.

I disagree. I think that private ventures are the only way to really expand into space. The stuff going on with Virgin Galactic is astounding. All of the great explorations in human history have been motivated by intense self-interest. We're human beings, and thus the only way to gets most of us motivated and keep us motivated is for there to be a concrete self-interest in doing the activity. Once the cold war was over, America's self-interest in pursuing manned space activities disappeared with it, which is exactly why the drive for the space program disappeared ~15 years ago. But now that private companies like Space X and Virgin Galactic are *seriously* pursuing space flights for their own person gains, now they're proceeding at an astounding pace. NASA was pretty much never going to produce a system that would allow the general public to go into space, but now Virgin galactic is just a couple of years away from the first flight into space that's open to the public. So thanks to them, in literally just 2 to 3 years - YOU will be able to go into space! You! And me too! *Anyone* who can scrape together $200,000 to spend will now be able to go into space, and that price will certainly go down over time. You can literally book your trip into space right now! THIS is how true space exploration becomes possible.

NB: I think NASA definitely still has a big role to play, because those private companies aren't interested in pursuing scientific discovery. Space-based scientific discovery is crucial to our country and species' self-interest.
 

lostngone

macrumors 65816
Aug 11, 2003
1,431
3,804
Anchorage
Pilot trivia time: when the weather bureau issues the pressure setting to pilots, it's offset by ten feet. In other words, it's calculated to be correct for altimeters that are ten feet off the ground, as was true back in the days of early airliners like the DC-3. If you're in a Cessna 172 with the instrument only five feet up, using the correct setting should falsely indicate that the plane is five feet below runway level. Very few people know this.

I used to design flight computers as a hobby.


Your information is a little dated. "the weather bureau" changed its name to the National Weather Service over 40 years ago.

Also even if it had a pressure senor what pilot in their right mind would want to use a iPhone/iPad as an altimeter. It wouldn't have the required accuracy, it couldn't be calibrated and the FAA wouldn't certify it.
 

jonnysods

macrumors G3
Sep 20, 2006
8,454
6,918
There & Back Again
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Mobile/8J2)

I love to see where this is all heading. Amazing.

And sort of scary at the same time.

But now I can know what my wife is thinking by putting a phone against her head.
 

zakool21

macrumors newbie
Aug 15, 2010
14
9
Your information is a little dated. "the weather bureau" changed its name to the National Weather Service over 40 years ago.

Also even if it had a pressure senor what pilot in their right mind would want to use a iPhone/iPad as an altimeter. It wouldn't have the required accuracy, it couldn't be calibrated and the FAA wouldn't certify it.

Not only that, but I've never seen a pressure altimeter that was accurate to within 25 feet, much less 10 or 5 feet.
 

kdarling

macrumors P6
Also even if it had a pressure senor what pilot in their right mind would want to use a iPhone/iPad as an altimeter. It wouldn't have the required accuracy, it couldn't be calibrated and the FAA wouldn't certify it.

An electronic sensor, being able to detect changes of two feet, is far more accurate than most mechanical altimeters.

They could of course be easily calibrated in software.

However, yes, it would take time to get certified.

Not only that, but I've never seen a pressure altimeter that was accurate to within 25 feet, much less 10 or 5 feet.

The FAA requires altimeters to be bench-certified as accurate within 20 feet up to a thousand feet. See Appendix E 14 CFR 43.
 

caspersoong

macrumors 6502a
Feb 27, 2011
604
30
Wow, interesting. Apple will only implement the best, as usual and be copied. And then other companies will include the lousy ones as well just for show.
 
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