Altimeter in the plane, does it work?

[raxxal]

Does any one know if the altimeter in a Suunto watch works while in the plane? I have a Casio Pathfinder, but the altimeter does not work in the plane.

How about the compass, does it work as well?

Thanks,
Raxxal

	Suunto Visit SuuntoWatches.com to see Suunto's full line of wrist top computers and compasses.

	Compass Compasses are sensitive, absolutely crucial instruments to precision navigation. The earth's magnetic field, inclination, and your longitude and latitude all influence the horizontal plane of a compass needle. As a result, compasses are balanced for different geographical zones. Suunto Compasses overcome this limitation to traditional compasses by using a simple 'Two Zone System'. With a Suunto Compass, the only 'balancing zones' are the northern and southern hemispheres. In addition to this innovation, certain Suunto Compasses come equipped with useful features like luminous needles and marks, centimeter/inch scales, magnifying glasses, clinometers, sighting notches, and more.

[blaine]

Air pressure must be measured to estimate altitude. So, if you are in a plane that does not adjust air pressure, it will work -- at least a little. You may find it sluggish during fast elevation changes.

However, you are probably concerned with commercial flights & I'd be surprised if you find any that don't adjust air pressure.

[uccprince]

It does work as long as you're not in a pressurized cabin. I've used my X6HR to measure and log flights in both a glider and private aircraft. Makes for some very interesting profiles.

All commercial flights are pressurized, and since the Suunto uses barometric pressure to estimate altitude, it doesn't work on these. The average long haul flight has a cabin pressure equivalent to being about 6000 feet above sea level.

The compass does seem to work on all flights.

	Suunto Visit SuuntoWatches.com to see Suunto's full line of wrist top computers and compasses.

	Suunto X6 HR - Click for more info Just when you thought a sports watch couldn't get any better, Suunto introduces the X6 HR, X6 HRM and X6-HRT. These are truly the next generation in sports watches, packed with all of the technology that Suunto enthusiasts have been craving. Designed for Cross Sports applications, the X6 writstops are functionally very similar to the Suunto X6 - but with the added benefits of a heart rate monitor.

	Compass Compasses are sensitive, absolutely crucial instruments to precision navigation. The earth's magnetic field, inclination, and your longitude and latitude all influence the horizontal plane of a compass needle. As a result, compasses are balanced for different geographical zones. Suunto Compasses overcome this limitation to traditional compasses by using a simple 'Two Zone System'. With a Suunto Compass, the only 'balancing zones' are the northern and southern hemispheres. In addition to this innovation, certain Suunto Compasses come equipped with useful features like luminous needles and marks, centimeter/inch scales, magnifying glasses, clinometers, sighting notches, and more.

[callysim]

the altimeter works by measuring air pressure. In a pressurized cabin, it will not work.

Do know that the altimeter for watches work by giving relative readings and not absolute readings.

[roadcoach]

The cabin pressure control system
continuously monitors the airplane’s ground and
flight modes, altitude, climb, cruise, or descent
modes as well as the airplane’s holding patterns at
various altitudes. It uses this information to allow
air to escape continuously from the airplane by
further opening or closing the cabin pressure
outflow valve in the lower aft fuselage.
The outflow valve is constantly being
positioned to maintain cabin pressure as close to
sea level as practical, without exceeding a cabinto-
outside pressure differential of 8.60 psi. Figure
10 shows the 767 cabin altitude schedule. At a
39,000-foot cruise altitude, the cabin pressure is
equivalent to 6,900 feet or a pressure of 11.5 psi
(about 450 feet less than Mexico City). In
addition, as the airplane changes altitude, the
outflow valve repositions itself to allow more or
less air to escape. The resulting cabin altitude is
consistent with airplane altitude. This is
accomplished within the constraints of keeping
pressure changes comfortable for passengers.
Normal pressure change rates are 0.26 psi per
minute ascending and 0.16 psi per minute
descending. The graph (somewhat concave) is availalabe here:
http://www.boeing.com/commercial/cabinair/ecs.pdf
page 6 (bottom)

Just eyeballing the table gives the following approximate results:

(cabin alt-> real alt)
(1,000->10,000)
(2,000->18,000)
(3,000->25,000)
(4,000->30,000)
(5,000->33,000)
(6,000->36,000)
(7,000->39,000)
(8,000->42,000)

	Suunto Escape - Click for more info The altimeter of the Escape 203 shows you your current altitude, vertical gain or loss from the start of a hike or climb, as well as your vertical ascent and descent rate in ft/h (m/h). Up to 20 altitude points can be stored into the memory for later reviewing. The one-logbook memory stores total vertical ascent/descent for the log, as well as the maximum and minimum altitudes reached during the activity. The unit also stores the accumulated vertical ascent/descent over a longer period of time. The altitude range extends up to 29,500 ft (9 000 m). The resolution is adjustable by the user to either 3ft (1 m) or 10 ft (5 m).

[ejunge]

OR...... You can listen for when the captain announces the cruise altitude...

[KouDy]

Originally Posted by ejunge

OR...... You can listen for when the captain announces the cruise altitude...

Signed .

Tho one more option would be to get Suunto X9/X10 and get altitude from GPS. It's not that accurate but sure it would be more accurate than barometric pressure inside the closed system created inside the pressurized cabin.

	Suunto Visit SuuntoWatches.com to see Suunto's full line of wrist top computers and compasses.

	Suunto X9i - Click for more info Introducing the Suunto X9i - the new and improved version of the Suunto's X9, voted "Best Product of 2004" by Fortune Magazine. Now available in two colors, the X9i combines GPS functionality with an altimeter, barometer, compass, and thermometer ... all these instruments, packed into a single watch.

	Suunto X10 Suunto commemorates 10 years with the Suunto X10. When you're trekking through a new frontier, adventure racing, biking, fishing, or conducting field operations, the Suunto X10 provides critical decision-making data. With full GPS functionality, including route planning and uploading, as well as outdoor essentials like an altimeter, barometer, and compass, the Suunto X10 wristop computer shows nature who's boss.

[ejunge]

I have tried repeatedly to do that, but I rarely can get a good enough signal.. I have seen video of someone who has though, but I seem to recall that they started when the plane was on the ground in order to get the initial lock

[roadcoach]

Here is a list of those that do NOT permit the use...Alaska Airlines
Air Tran
America West Airlines
American Airlines (Changed again as of October 2009)
Britannia Airlines
El Al Airlines (Israel)
Frontier Airlines (as of June 2008)
Hawaiian Airlines(*)
Horizon Airlines(*)
Iberia Airlines(*)
Lufthansa Airlines
Mexicana airlines
Midway Express
Monarch Airlines
Ryanair (Irish) (as of January 2008)
Spirit Airlines
US Airways (was US Air) (as of December 2007)
Varig Airlines
Virgin Airlines (As of March 2007)
see I want my GPS! - USATODAY.com and list of airlines as of October 2009 Airlines which APPROVE/DISPROVE GPS use in Flight

[KouDy]

Oh that's interesting. Would you also have idea why do they forbid using GPS devices on board?

I know basically all providers are banning any electrical devices while take off, landing and taxi. But during flight you are usually permited to use devices like mp3 players. Mobiles phones still being banned on most flights. Could possibly getting GPS signal (you are not really transmitting no?) interfere with flight operating devices? Not even mobiles do interfere in any significant scale, it's just security measure. But then again, mobiles do transmit actively...

	Suunto X9i - Click for more info Introducing the Suunto X9i - the new and improved version of the Suunto's X9, voted "Best Product of 2004" by Fortune Magazine. Now available in two colors, the X9i combines GPS functionality with an altimeter, barometer, compass, and thermometer ... all these instruments, packed into a single watch.