Text 13339, 106 rader
Skriven 2014-03-30 16:01:10 av Ward Dossche (2:292/854)
  Kommentar till text 13265 av alexander koryagin (2:5020/2140.2)
Ärende: Re: MH370 update on my March 17th message
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Alexander,
 
ak> 1. You can go around a base station and your phone will be in
ak> connection. It means that a base station has a circle diagram.
 
Yes, on average 6km.
 
ak> 2. At sea, the cell phone can work when a base station is visible
ak> directly, it depends on earth curvature. If you are on the surface the
ak> distance is small (a few kilometers), when you are high above - the
ak> distance is bigger. And the base station itself will not be below you --
ak> it will be at horizon, hided by no obstacles.
 
All fine. It can be easy calculated but from mu head I seem to remember that
from appr. 35.000ft up you have a direct-line of appr.80 nautical miles, some
140-150km. The transmitter power however does no reach that far, about 10km and
you're done ... which is another reason why at 35.000ft there is no exterior
cellphone signal.
 
ak> I read about reliable facts that the cell phones of MH370 passengers
ak> could receive calls for many hours, but nobody answered.
 
I read that initial report too and with hindsight I do not believe it. It's
technically impossible.
 
ak> Well, if the investigators do tests it would be good to check the
ak> possibility to send SMS while flying over Malaysia.
 
You really do not understand, do you? Unassisted cellphone service in a flying
aircraft is technically impossibe.
 
ak>WD> Several in the industry have claimed that the alleged cellphone
ak>WD> calls from airplanes during 9-11 did not happen for that matter.
ak>WD> Probably they were credit card calls from onboard satellite phones
ak>WD> which at the times were pretty successful... and expensive.
 
ak> I read some controversial articles on this account.
 
Yeah? I've seen such claims too. In the telecomworld with about 20 providers
and some of the suppliers we researched this in workgroups and the conclusion
was that it couldn't happen, technically impossible, if the traffic didn't go
via a satellite.
 
ak> The pilots could be alive for some moments. But air pressure pumps
ak> could be unworkable when some power cables failed. The idea of their
ak> behavior is simple - they tried to reach their home country. It would be
ak> strange to continue or choose other directions.
 
An explosive decompression gives you barely the time to reach for your oxygen
mask, it's not like shown in the airplane videos. All air is sucked-out ...
also the air in your lungs, the air from your stomach if it contains any, all
the gases from intestines are sucked-out in a second or two. The pilot has 12
minutes of available oxygen to dive to an altitude where normal breathing was
possible, instead it did climb even higher.
 
ak> The area to the north of Kuala Lumpur is one of the most dense
ak> populated area of the world.
 
The area where MH370 allegedly crossed west over Malaysia is about 600km north,
is virtually uninhabited and there is no air traffic control at all.
 
ak> That accuracy of this trajectory is very unreliable. Well, if we
ak> knew the trajectory we would find the plane easily.
 
The accuracy is pretty reliable. Remember, the moment that data was used
immediately hundreds of floating pieces of debris were found. Still to be
identified.
 
ak> Electricity must be in the plane even when its engine don't work. So
ak> there are some internal generators that provide energy.
 
There are no internal generators. There are batteries but they are small and
don't last long. Further MH370 had a minimum equipment list notification that
its APU (Auciliary Power Unit, in the tail) was not function.
 
If a plane is in-flight and has no engines, there is no electricity other than
what's left in the batteries and provided by the RAM-turbine.
 
Gliding wihtout an engine function cannot go on forever. Contrary to
glider-planes that can climb with warm air pockets, a disabled jetliner as only
one direction: down. To keep lift it needs to point the nose down so that there
is sufficient air over the wing surfaces. But it will always descend.
 
The glide ratio of a 777 is 12:1 meaning it can glide 12 times the distance of
its altitude. So when a 777 cruises at 10.000 meter, it can glide a maximum of
120km and then be at sea-level. If it was above Colorado for examble which is
elevated, it would be 99km.
 
ak> The plane behavior suggests that the pilots were dead and the plane
ak> was controlled by auto-pilot.
 
If it flew by autopilot, then it should've concluded its flight plane and
crashed in China somewhere.
 
ak> Although, if the navigation system was severely damaged, the pilots
ak> for 4 hours flew blindly, in complete darkness, until the dawn showed
ak> them where the east was. But it was too late.
 
Even modern electronic airplanes still have some dials. They do have a regular
compass, an artificial horizon and some other 'primitive' things. There's no
way a pilot can fly in a 90ø wrong heading for 4 hrs and not know.
 
 \%/@rd 

--- D'Bridge 3.99
 * Origin: Many Glacier / Protect - Preserve - Conserve (2:292/854)