Rules of Thumb
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Joined: Oct 2009
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From: Pinchbeck
Rules of Thumb
Hi fellow aviators I would like to know all your rule of thumb info. It seems that whilst training there is a lot of maths etc, which then you have to use the wiz wheel for. Only to find out when talking to more experienced pilots there is a rule of thumb for that which could be easier.Can we all share our Rule of Thumb info? no matter how small it is just jot it down.
Joined: Aug 2007
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From: Back in the real world
Crosswind - the simple (on final) mental calculation
Split the watch face into 4 quarters - 1 to 3 = 1/4, 3 to 6 = 1/2, over 6 = full crosswind
Wind 10-30 deg off runway is in the first 1/4 - take 1/4 of wind as crosswind
Wind 30-60 deg off runway is in the second quarter - take 1/2 of wind as crosswind
Wind 60 deg + take all of wind as crosswind
Split the watch face into 4 quarters - 1 to 3 = 1/4, 3 to 6 = 1/2, over 6 = full crosswind
Wind 10-30 deg off runway is in the first 1/4 - take 1/4 of wind as crosswind
Wind 30-60 deg off runway is in the second quarter - take 1/2 of wind as crosswind
Wind 60 deg + take all of wind as crosswind
Joined: Jan 2005
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From: Hotel this week, hotel next week, home whenever...
From your knuckle to the tip - how long is your thumb?
On an average spread - how wide is your hand from thumb to little finger?
It helps with diversion planning whilst in the air.
On an average spread - how wide is your hand from thumb to little finger?
It helps with diversion planning whilst in the air.
Joined: Aug 2007
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From: Horsham
Crosswind
Even simpler, and more accurate, than the previous reply, take the number of degrees the wind is off the runway heading, divide by 10, then divide by 6. The crosswind is that fraction of the wind strength.
So if Rwy is 020 and wind is 040/12k, then wind is 20 degrees right of rwy heading. So 2/6 of 12k = 4kts xwind from the right
Example: Same rwy and wind stength but the wind direction changes
Wind 020 -diff = 0, so 0/6 = no crosswind
Wind 030 - diff = 10, so 1/6 = 2kts
Wind 040 - diff = 20, so 2/6 = 1/3 = 4kts
Wind 050 - diff = 30, so 3/6 = 1/2 = 6kts
Wind 060 - diff = 40, so 4/6 = 2/3 = 8kts
Wind 070 - diff = 50, so 5/6 = 10kts
Wind 080 - diff = 60, 6/6 = 12kts Full crosswind component.
So if Rwy is 020 and wind is 040/12k, then wind is 20 degrees right of rwy heading. So 2/6 of 12k = 4kts xwind from the right
Example: Same rwy and wind stength but the wind direction changes
Wind 020 -diff = 0, so 0/6 = no crosswind
Wind 030 - diff = 10, so 1/6 = 2kts
Wind 040 - diff = 20, so 2/6 = 1/3 = 4kts
Wind 050 - diff = 30, so 3/6 = 1/2 = 6kts
Wind 060 - diff = 40, so 4/6 = 2/3 = 8kts
Wind 070 - diff = 50, so 5/6 = 10kts
Wind 080 - diff = 60, 6/6 = 12kts Full crosswind component.
Joined: Jan 2001
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From: In the boot of my car!
RULES OF THUMB
Dont get your thumb in the way when hammering in nails
Another one? for your descent point multiply your altitude by 3 ie 30,000 just take the 30x 3= 90 miles or 9000 feet 9 x 3 = 27 miles out.
Pace
Dont get your thumb in the way when hammering in nails
Another one? for your descent point multiply your altitude by 3 ie 30,000 just take the 30x 3= 90 miles or 9000 feet 9 x 3 = 27 miles out.
Pace
Joined: Apr 2009
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From: In a house
beatnik,
dangerous one yours, a wind that is 30 deg off runway heading simply gives a crosswind component of half the wind speed. Your example gives a 2 kt crosswind when it should be 6. Mathematically it is the sin of the angle multiplied by the windspeed. Rules of thumb work but not this one.
Stick with the clock face and you can't go wrong. Failing that if it feels to strong it probably is.
Wind 030 - diff = 10, so 1/6 = 2kts
Stick with the clock face and you can't go wrong. Failing that if it feels to strong it probably is.
Joined: Aug 2003
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From: Surrey
beatnik,
dangerous one yours, a wind that is 30 deg off runway heading simply gives a crosswind component of half the wind speed. Your example gives a 2 kt crosswind when it should be 6. Mathematically it is the sin of the angle multiplied by the windspeed. Rules of thumb work but not this one.
Stick with the clock face and you can't go wrong. Failing that if it feels to strong it probably is.
dangerous one yours, a wind that is 30 deg off runway heading simply gives a crosswind component of half the wind speed. Your example gives a 2 kt crosswind when it should be 6. Mathematically it is the sin of the angle multiplied by the windspeed. Rules of thumb work but not this one.
Stick with the clock face and you can't go wrong. Failing that if it feels to strong it probably is.
Joined: Feb 2007
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From: Amsterdam
In feet, one would hope
although wouldn't use it above about 50 degrees as it becomes very inaccurate, but up to that, very close to the sine values!
Fleet Manager
Joined: Aug 2006
Aviation Qualifications: CPL
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From: Ontario, Canada
Quote:
- Groundspeed in knots times five is the vertical speed required.
In feet, one would hope
- Groundspeed in knots times five is the vertical speed required.
In feet, one would hope
Also:
Nothing ever happens fast enough in aviation, unless something is going wrong...
Joined: Mar 2007
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From: Right here
One I use on almost every flight: Dependence on weight for approach speed, best glide speed, VX, VY, VA: The percentage change in speed is half the percentage change in weight.
Penetration speed: When gliding with a head wind, increase gliding speed by a quarter of the wind speed. When gliding with a tail wind, glide slightly slower, but never slower than the minimum sink speed.
IAS -> TAS: Two percent per 1,000 ft.
Crosswind correction: 1 knot crosswind per 1 degree correction, per 60 kts GS. E.g., 10 kt crosswind component at 120 kts GS requires 5 degrees correction.
Penetration speed: When gliding with a head wind, increase gliding speed by a quarter of the wind speed. When gliding with a tail wind, glide slightly slower, but never slower than the minimum sink speed.
IAS -> TAS: Two percent per 1,000 ft.
Crosswind correction: 1 knot crosswind per 1 degree correction, per 60 kts GS. E.g., 10 kt crosswind component at 120 kts GS requires 5 degrees correction.
