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neilmck

Jumping in metres

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Having jumped in feet in the UK back in the day, after a 20+ year break I now find myself living in France and jumping in metres.  

It is a constant cause of stress being in free-fall looking at my altimeter and never being able to remember if I have to multiply or divide by 3. Thank God it is colour coded, there is no way I will ever buy a digit altimeter.

After discussing with some friends I understand that French parachutists are unique in the aviation world for using metres (even our pilot uses feet).  Is this true?  Do any other countries jump in metres?

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I use an altimeter in metres because all the other parachutists I jump with are agreeing on altitudes in metres and things would only get confused if I was using feet.

The main issue I have is underestimating the time left to break-off.  I have been using metres for everything without exception since moving to France over 20 years ago, and for most of the dive I will think in metres yet just before break-off when estimating how much time is left my brain subconsciously switches to feet. So for example I will estimate there are only 2 seconds left until break-off when there is in fact 6 to 7 seconds left.

After a few more years if my my brain ever sorts itself out I'll have another look at digital altimeters.

 

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2 hours ago, piisfish said:

Yet aviation is mostly worldwide in feet. 

Yes, I agree this one is a weird one.  I cannot understand how one ever started jumping in metres when their pilots have always used feet.  I'd have thought they would have used feet just to avoid confusion with the pilot.

At my home DZ one of our parachutists started jumping aged 16 and she celebrated her 80th birthday in January.  If anyone knows why they switched to metres, she will.  I'll ask her next time I'm at the DZ and report back. 

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I believe that most skydivers in the metric world do not consider themselves aviators. Moreover due to the precision of our instruments and the decision speed we need, it is better to jump with the units you are most familiar with. 

In case of mixed units jumps, do the rough calculations on the ground prior to jumping, and agree on altitudes during the briefing. 

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10 hours ago, piisfish said:

I believe that most skydivers in the metric world do not consider themselves aviators. Moreover due to the precision of our instruments and the decision speed we need, it is better to jump with the units you are most familiar with. 

In case of mixed units jumps, do the rough calculations on the ground prior to jumping, and agree on altitudes during the briefing. 

In Canada we jump in feet. Pilots fly in feet. Pretty had to go metric with the Imperialist elephant south of us.

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In Canada we jump in feet. Pilots fly in feet. Pretty had to go metric with the Imperialist elephant south of us.

On the hit United States of America TV show, How I Met Your Mother, there is a flashback to a concert by the  Canadian singer,  Robin Sparkles. At the concert, behind Robin was a banner that read, "Consider Questioning Authority, Please."

Robin got it. 

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Finally got to speak with the 81 year old parachutist at the DZ.  She explained to me that when she started they didn't use altimeters, just their eyes.  Then they started using aircraft altimeters that where huge and kept flapping around when in freefall.  The aircraft altimeters in France were in meters at the time.  It was at a later date that there was an international agreement for pilots to standardise on feet, the parachutists continued to use meters.

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(edited)

Here in Iran we also use metric system and abviously people are familiar with . 

the main problem is we train skydiving students based on USPA's SIM , and SIM uses feet .

it is really confusing not only for learners also for instructors .   

Edited by iranianjumper

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(edited)

Dear iranianjumper,

The last thing you want is students fixating on mathematical calculations as they rapidly fall towards the planet. May I suggest reducing confusion by loaning wrist-mounted, metric altimeters to your students?

Instructors can wear two altimetres: whatever they like on their wrist along with a metric altimeter on their chest strap. Their student should be able to read an instructor's chest-mounted altimeter if it has a big enough face.

If you want to simplify discussions with your pilot. stick an extra metric altimeter to the dash board and ask your pilot to "zero" it before take-off.

Your pilot will keep his/her regular altimeter set to feet above sea level because that is what other pilots and air traffic controllers understand.

When I used to jump in France and Germany, I still wore my "feet" altimeter and did rough calculations (3 to 1) to confirm that I was "singing from the same sheet of music" as my companions wearing metric altimeters.

In the end, it makes little difference whether you pull at 1 kilometre or 3,300 feet or 3,000 feet because the canopy ride lasts about the same number of minutes.

 

Edited by riggerrob
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3 hours ago, iranianjumper said:

Here in Iran we also use metric system and obviously people are familiar with . 

the main problem is we train skydiving students based on USPA's SIM , and SIM uses feet .

it is really confusing not only for learners also for instructors .   

Is there any reason you can't convert the feet to meters?

Continue to follow the USPA rules for altitudes, but work in meters instead?

For example, a D license has a minimum pull altitude of 2500 feet. That converts to 762 meters. So call it 775m. 


I know there are USPA foreign affiliates in other places (and just about everyone but the US uses metric). 
Makes me wonder how they do it.

 

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On 10/16/2020 at 8:59 PM, Matija said:

I would say that metric skydiving instruments are used in probably every country in the world where metric system is implemented in their schooling and education system.
Same goes for imperial system countries.

You'd be wrong. :)

In the Netherlands, skydivers use feet for altitude. We teach students that their hard deck is 2000 ft, without confusing them with conversion factors.

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3 hours ago, Baksteen said:

You'd be wrong. :)

In the Netherlands, skydivers use feet for altitude. We teach students that their hard deck is 2000 ft, without confusing them with conversion factors.

Yet, they still try to convert them unintentionally because that's the way they're thought since young age. :)
As riggerrob said above, "
The last thing you want is students fixating on mathematical calculations as they rapidly fall towards the planet".

Edited by Matija

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28 minutes ago, Matija said:

Yet, they still try to convert them unintentionally because that's the way they're thought since young age. :)
 

And you know this how exactly?

During the early stages of the FJC there is occasionally a student who out of habit says 2000 meters instead of 2000 feet. But that is easily rectified.
Moreover, unlike the Iranian example above, Dutch altimiters, course material and teaching consistently use feet.

To my knowledge there has never been an incident, near inicdent or even occasion where a Dutch student indicated they were confused about when to open their parachute due to having to make mathematical conversions.

You pull your main at 3000 feet (which is when the needle is pointing at 3000 feet). Later, you learn to estimate the altitude for yourself and you KNOW you're at approximately 3000 feet. But nobody is taught from a young age how to estimate altitude, especially when suspended in mid-air or falling.

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I live and jump in Serbia where we use meters. Pilots use feet (because that's the international convention I guess), but jumpers use meters and have meter altimeters. When a pilot is new with skydiving, you have to make sure you communicate if you're going to 3000 feet or meters :)

My 117th jump was in the US where I rented equipment, and guess what, the altimeters are in feet. Before the jump, I converted the few critical altitudes I need (deployment/decision altitude/hard deck/no cutaway) and just watched for those. There's no real reason to do any maths, you're not solving differential equations up there. You have series of altitudes upon which you base your decisions (unless you're swooping for example where you need a bit more precise numbers I guess). For what is worth, you could have them marked as A, B, C, D... on the altimeter and never know how they translate to real world coordinates.

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Dear Neilmick,

The planet was divided between metric countries and imperial countries until the United States Army Air Force won the Second World War in 1945. Since the USAF won the war single-handedly, they forced the rest of the planet to fly in feet.

A few of those silly communist countries continued measuring altitude in metres, but they slipped out from under the Soviet yoke circa 1990.

Sarcasm alert! Please do not tell the USAF anything different as you might damage their delicate egos.

My key point is that students should only be asked to learn one system of measurement. If the student has only learned metres in elementary and high school, it is silly to teach them feet when they start skydiving.

Telling students to open their main parachutes (aka. "pull handle number 1") at 1,000 metres is easy to remember.

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