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The altitude and thermal specs are linked. At higher altitude, you have less air molecules to take away the heat. Because of this, a device that will heat up to a certain temperature at sea level will heat up to a higher temperature at 10,000 feet and an even higher temperature at 15,000 feet, assuming all else is equal. Put the other way, a device that will function up to a certain ambient temperature at sea level will only operate to a lower ambient temperature at 10,000 feet and an even lower ambient temperature at 15,000 feet.
I do not own an iPad, so I have no personal experience. However, there have been a lot of reports about the iPad getting too hot and shutting down when exposed to direct sunlight. These are reports at ground level and some are claiming that it takes a little as 10 minutes. A Google search reveals million+ hits, including the following from cNet and Applr's own discussion forum:
http://reviews.cnet.com/8301-31747_7-20001749-243.html
http://discussions.info.apple.com/thread.jspa?threadID=2396808&start=0&tstart=0
Quite predictably, this has led to a good ol lawsuit. Here's a news article and the actual filing:
http://www.bloomberg.com/news/2010-07-26/apple-sued-over-claims-ipad-tablet-overheats-in-sunlight-warm-conditions.html
http://www.docstoc.com/docs/document-preview.aspx?doc_id=48234124
The following link, claiming to answering on behalf of iPad users, acknowledges the existence of the problem and mocks people for being unreasonable for trying to use the iPad in situations where these problems can reasonably be expected to occur (their opinion of what is "reasonable"):
http://www.theipadguide.com/content/books-have-better-heat-tolerance-ipad/7174901
I do not know if any of these reports are true, if the problems are endemic or experienced by a few outliers. What I can tell you is that whatever the experience at sea level, the thermal performance will be worse at 8,000 feet in a IV-P and worse still at 15,000 ft in a Legacy -- that is basic physics.
It is your call how much credence you want to put in these reports. Whatever you decide, I would strongly urge you to thoroughly test whatever hardware/software you want to use and push it to the limit in a realistic environment before you actually put it in service. The cockpit is no place for surprises!
Regards,
Hamid
Chris Zavatson wrote:
Thanks for all the replies.
One more question. The apple specs show maximum operating altitude of 10,000 feet. If there is a good technical reason for this, it would seem rather limiting for our en-route use. The operating temperature is also kind of pushing the upper limit when on the ground on hot summer days. The temperature issue can be somewhat controlled, but the altitude exposure not so much. Is this a CYA or other generic limit?
Environmental requirements
* Operating temperature: 32° to 95° F (0° to 35° C)
* Nonoperating temperature: -4° to 113° F (-20° to 45° C)
* Relative humidity: 5% to 95% noncondensing
* Maximum operating altitude: 10,000 feet (3000 m)
Chris Zavatson
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