One thought about possible thermal shut down at a time when use of the gadget is crucial to safety of flight is to consider the logical exposure to the offending conditions. 

The argument could be that when you are on an IFR flight and in IMC conditions, you likely will not have direct sunlight heating up the cockpit.  I think most of us have experienced going from sunlight to clouds at almost any altitude and noticed how rapidly the temperature in the cockpit drops when the greenhouse effect is lost.

Of course the counter argument would be that in the situation where one is VFR on top dropping into a low IFR approach, conceivably the iPad would not be functional in the heat generated while above the clouds and then would not be usable for the ensuing approach even though the temperature in the cockpit might drop rapidly.

Obviously, Hamd’s recommendation to thoroughly test in all conditions prior to relying on the iPad  without a backup would be prudent. 

Regards,
John Barrett

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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