Our mechanic just replaced his skydrol covered phone with a new 3G iphone. I was wondering if there are any good, but simple (he is a mechanic after all) apps that would let him plot a lat-long waypoint or two and then follow along using the iphone’s GPS. That would give him the only GPS in the airplane! Might be kind of handy crossing the pond too, you know those days when one INS says turn right and the other one says turn left… 
John in Beirut
You know, I don’t know the answer to your question, but you should be an Iphone salesman 
as this may be my “crossover” justification when my Verizon contract expires in December.
Would be even cooler (if it’s not done already) to get XM weather services into the device, talk about one stop shop device.
XM Weather would really be great on the iPad. The ForeFlight applications - I use two, AOPA Airports and ForeFlight Charts - seem ideally suited for the device. I keep thinking of buying the full version.
Why would you need XM weather on the iPad or iPhone. It has an internet connection???
Does the 3G network operate from the comforts of 7000 feet?
I don’t spend any time at that ALT… So I can’t answer that
At that altitutude for you, all electronic devices are probably in their off position and stowed for landing 
Seriously though, before the digital age of cells, my analogue cell worked wonderfully in the air at 7000, but now my new and improved digital chokes unless I fly lower then 3000.
So I thought maybe you had some insight on the 3G network availability near my service ceiling 
You won’t find many 3G towers in the middle of the pond Allen. And no WiFi either Jason.
Once I received a phone call at 10000 feet going from HPN-ACK. Usually though, if I forget to turn the phone off before departure, my message tone will sound at about 2000 feet.
Jason, don’t you ever repo FXE-MCO? IIRC that’s usually flown at 7000 feet. 
I’ve gone to MCO but not at 7k more like 17,000 or above.
GOV’T PREFERRED - 11,000’ TO 17,000’
I use to think 8k was WAY up there and now I get uncomfortable if I have to spend anytime below 10,000
MCO-JAX maybe? One of those is really low for some reason I can’t remember…
MIA-FXE rocking that .1 flight at 2500! but I can call and text at that ALT
I went missed last winter at Key West and called company on my phone at like 4k to tell them I couldn’t make it in…
Flyboy’s just letting go of the gear handle going through 7,000.
I’m pretty sure that Iphones, like most other GPS-enabled cell phones, have Assisted GPS which requires there be a cell tower somewhere in the neighborhood. So, no love for pond crossing.
Did a little bit of research, Assisted GPS apparently can come in different configurations, some requiring a connection to a cell tower, but there are stand-alone assisted GPS phones.
Standalone mode is important. This means you do not need the carrier network at all to use GPS and usually you can install any GPS mapping software to boot. This is how the HTC Tilt and modern BlackBerries work and the Sprint Q9c
So, does the iphone have just assisted GPS or is it also a true GPS?
No idea. Seems impossible to find an answer. Someone has to try it out 
.
The link below makes me “think so” that it is a true GPS. It says in the link provided below.
“The location search works on mountains, oceans, or on the move, according to the company”
ipodnn.com/articles/08/10/06 … one.touch/
Another link from Gmap support says
How can we locate the current position if the GPS signal is not available?
You can locate the current position through cell tower or Wi-Fi manually.
gmapdrive.com/servlet/gmap.s … faqServlet
I only have an Itouch, so I can’t test it myself.
Should have had our mechanic get his out today over the Mediterranean.
If anybody finds out before I do let me know, thinking of getting one.
Didn’t anyone think to check on the iPhone page to find out if it has real GPS?
The specification page says it has assisted GPS: apple.com/iphone/specs.html
The following are excerpts from the user’s guide:
iPhone uses Location Services to determine your location. Location services uses available information from cellular network data, local Wi-Fi networks (if you have Wi-Fi turned on), and GPS ( iPhone 3G or later; GPS not available in all locations). This feature isn?t available in all areas.
When airplane mode is on, (airplane icon) appears in the status bar at the top of the screen. No phone, radio, Wi-Fi, or Bluetooth signals are emitted from iPhone and GPS reception is turned off, disabling many of iPhone?s features. You won?t be able to:
…
Get map locations
Location Services allows applications such as Maps Camera, and Compass to gather and use data indicating your location. Location Services doesn’t correlate the data it collects with your personally identifiable information. Your approximate location is determined using available information from cellular network data, local Wi-Fi networks (if you have Wi-Fi turned on), and GPS (iPhone 3G or later; GPS may not be available in all locations).
One non-Apple site I found says the iPhone 3G has GPS with A-GPS support:
gsmarena.com/apple_iphone_3g-2424.php
The part about GPS not being available in all areas indicates to me that the GPS isn’t as good as a dedicated GPS unit.
So the bottom line seems to be: If you want a real GPS then buy a dedicated GPS unit, not an iPhone. Even though it’s on extra item to carry, I’ve found that a dedicated GPS unit is much better than one bundled into the phone.