Difference between revisions of "Mobiles at altitude"
Latest revision as of 01:41, 9 July 2012
Ask most people how we know the 9/11 flights were hijacked, and they'll tell you about the phone calls from passengers and flight attendants, the talk of stabbings, mace, bomb threats, and more. But not everyone accepts these calls as genuine. One commonly repeated claim is that cellphone calls above 8,000 feet were essentially impossible, for instance, as David Ray Griffin explains:
The “impossible” claim is most often associated with Professor AK Dewdney, in a study of his own called "Project Achilles". He actually tried making calls at various altitudes, and concluded that "cellphone calls from passenger aircraft are physically impossible above 8000 feet and and statistically unlikely below it". There are reasons to question Dewdney’s conclusions, though. Read more here.
And if you read the Griffin quote carefully, you'll find another important qualification in the mention of airphones. These are seatback phones designed to work at altitude, and testimony at the Moussaoui trial explained that the vast majority of Flight 93 calls (this flight had more calls than any other) were made this way. The list was Lauren Grandcolas (airphone); Mark Bingham (airphone); Joseph DeLuca (airphone); Linda Gronlund (airphone); Jeremy Glick (airphone); Todd Beamer (airphone); Sandra Bradshaw (airphone); Thomas Burnett Jr (airphone and probable cellphone); CeeCee Lyles (airphone and cellphone); Marion Britton (airphone); Honor Wainio (airphone); Waleska Martinez (airphone); Ed Felt (cellphone) (Source). There's no dispute that airphones would have been able to work on 9/11, which only leaves us with a very few calls that can be regarded as "suspicious".
Still, it could be argued that you need only show one call was impossible to expose the truth, so it's worth considering the issue in more detail. Exactly what sort of range can you expect to achieve with a mobile? In principle the distances look impressive:
22 miles would be over 100,000 feet. You can’t apply such a simple rule, though, because mobile networks aren’t designed to serve the skies. Others use this quote as an example of professional scepticism.
Although the full quote tells a slightly different story.
Below a certain altitude? What might that be?
So it may work at 30,000 feet, although only momentarily? Apparently the New York Times agrees:
Note particularly the point that “some older phones” may work at twice the altitude of newer digital systems, up to 50,000 feet. Were any of those in use on 9/11? We don’t know, but it’s worth considering before you suggest the calls were “impossible”.
This question has also been addressed in The Hindu:
And in Wireless Week:
Then there’s also this report about an FCC study, talking about mobile use “at high altitude”:
John Sheehan, who headed a study into the supposed effects of mobile use on aircraft systems, says mobiles are used on planes "thousands of times every day", that he regularly uses a mobile in the sky himself, and that they could be allowed to be used above 10,000 feet - why would he say that, if he believed this wasn't possible?
And Popular Mechanics' "Debunking 9/11 Myths" quoted a couple of industry figures who accepted that calls at altitude were possible:
Backing up these claims are further reports about people using their phones in flight. These are stories from 9/11:
This guy was arrested and jailed for preparing to send a text message at 31,000 feet (don’t know if he did or not, but if there was no signal you’d have expected him to turn it off as requested):
Here’s a pilot calling his wife, perhaps from 15,000 feet:
And there are various anecdotal reports, which prove nothing in themselves, but we find it hard to believe that they’re all fictional.
IEEE Spectrum even ran a test to check this, and discovered cellphones were being used within commercial aircraft cabins (and not just while taking off or landing, where altitudes will be lower):
Sceptics still point to the case of Tom Burnett. His wife says she recognised his caller ID for the first call, and we know the times she says these were made:
The NTSB Flight Data Recorder report tells us about the altitude around these times:
How were the calls made? Jere Longman's Among the Heroes tells us about the first three:
We have two cell phone calls according to Longman, then, a quick ten seconds at 35,000 feet, and a longer one at around 20,000 feet. It's plainly not easy to connect at the higher altitude, otherwise more would have done so, but we don't believe it's been shown to be at all implausible. We've already referenced several articles suggesting it may well be possible to successfully connect at these altitudes, especially for a very brief call.
One argument against the use of airphones involves pointing to press reports specifically saying that a mobile was used. Here's an example:
The problem with relying on a story like this is we don't know if the reporter verified it. Did he really try to find out whether Hanson used a mobile, or an Airfone? We don't think so, because it makes no difference to the story he's telling at all. And a sentence later in the same story confirms this:
"Those with no mobiles could only pray silently".
Whoever wrote this clearly didn't know that the planes had Airfones, and simply assumed any calls were made from mobiles instead. And the author's assumptions are evidence of nothing at all.
Other articles simply use terms like “cell phone” incorrectly. Here’s a graphic from the Post Gazette, for instance.
Take a look at point #12, where it’s suggested that Beamer made a “cell phone call”. Where’s the evidence for that, especially as we know he spoke to an Airfone operator? Looks to us like this is simply wrong, and another example of how reports use terms like “mobile” and “cell phone” for convenience, without verifying whether they were true.
Inconsistencies elsewhere are easy to find. One Flight 93 article tells us this:
He was in the lavatory and so must have used a mobile. However, look elsewhere and we find:
So maybe not.
And not all mobile calls are automatically suspect.
No reason to believe this wasn't a mobile call, but it was only minutes before the crash, and other reports suggest the plane was very low:
No altitude issues here.
None of this is 100% conclusive, but it does illustrate the point: there’s plenty of support for the idea cellphone calls can be made from altitude, and the Airfones were available for everyone else. Overall we see no compelling reason to believe the calls weren't genuine.