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-   -   Rules of thumb (https://www.pprune.org/tech-log/340591-rules-thumb.html)

flying jocks 26th August 2008 15:42

Rules of thumb
 
Does anybody have any useful rules of thumb? For example this is one that I was told the other day:

Whilst flying a normal (assume 3º glide) approach, the last point at which you should put the gear down to achieve stability criteria before touchdown is calculated as so:-

Look at the g/s from your Nav. Display and multiply by 10, then add the runway elevation to give you the answer in feet (QNH). I fly the A319 and incredibly it seems to work.

Example:

Thr. elevation = 1500ft
Groundspeed = 190 Kts

190 X 10 = 1900
plus elevation of 1500 ft = 3400' AMSL.

Below this point the a/c will not slow down quick enough to be stable at 1000 ft AAL.

FJ

Cardinal 26th August 2008 17:27

That seems clever, I'll have to try it.

PA38-Pilot 26th August 2008 18:36

It might work at sea level, but don't try it at any high altitude airport with a light airplane. You won't make it.

mvsb1863 26th August 2008 18:56

Flying Rules

1 - Every takeoff is optional. Every landing is mandatory.

2 - Flying isn't inherently dangerous. It's crashing that's dangerous.

3 - If you push the stick forward, the houses get bigger. If you pull the stick back, they get smaller. If you keep pulling the stick all the way back, they get bigger again, quickly, very quickly.

4 - It's always better to be down here wishing you were up there than up there wishing you were down here.

5 - The only time you have too much fuel is when you're on fire.

6 - The propeller is just a big fan in front of the plane to keep the pilot cool. If it stops, you will see the pilot start sweating.
7 - When in doubt, hold on to your altitude. No one has ever collided with the sky.

8 - A "good" landing is one from which you can walk away. A "great" landing is one after which the airplane can still be used.

9 - Learn from the mistakes of others. You won't live long enough to make all of them yourself.

10 - You know you've landed with the wheels up if it takes full power to taxi to the ramp.

11 - The probability of survival is inversely proportional to the angle of arrival.

12 - In the ongoing battle between objects made of aluminum going hundreds of miles per hour and the ground going zero miles per hour, the ground always wins.

13 - Good judgment comes from experience. Experience usually comes from bad judgment.

14 - It's always a good idea to keep the pointy end going forward as much as possible

15 - Gravity is not just a good idea. It's the law. And it's not subject to appeal.

16 - Keep looking around. There's always something you've missed.

17 - The three most useless things to a pilot are the altitude above you, runway behind you, and a tenth of a second ago. 18 - Never let an aircraft take you somewhere your brain didn't get to five minutes earlier.

19 - Stay out of clouds. The silver lining everybody keeps talking about might be another airplane going in the opposite direction. And mountains hide in clouds.

20 - Always try to keep the number of landings you make equal to the number of take offs you've made.

21 - There are three simple rules for making a smooth landing. Unfortunately no one knows what they are.

22 - You start with a bag full of luck and an empty bag of experience. The trick is to fill the bag of experience before you empty the bag of luck.:rolleyes:

stilton 27th August 2008 07:09

Wherever you go, there you are

babemagnet 27th August 2008 08:37

Nice Rulles of thumb:

5 times your groundspeed is the VS you need on a 3 degrees glideslope example groundspeed is 150 times 5 is 750 feet per minute descent

6 times the altitude you are flying you can receive the atis or a vor example you fly 30,000 feet 6 times 30 is 180 nm you can receive atis or vor (in good conditions no mountains etc etc)

Max Angle 27th August 2008 09:16


5 times your groundspeed is the VS you need on a 3 degrees glideslope example groundspeed is 150 times 5 is 750 feet per minute descent
Same answer, different working. Add a zero to the groundspeed and divide by 2. Much easier.

Wingswinger 27th August 2008 09:43

True Airspeed "Squared" Rule
 
A quick way to calculate TAS from IAS:

Sea Level TAS = IAS

5,000ft TAS = IAS + 9% (3 squared).

10,000ft TAS = IAS + 16% (4 squared).

15,000ft TAS = IAS + 25% (5 squared).

20,000ft TAS = IAS + 36% (6 squared).

25,000ft TAS = IAS + 49% (7 squared).

30,000ft TAS = IAS + 64% (8 squared).

35,000ft TAS = IAS + 81% (9 squared).

40,000ft TAS = IAS + 100% (10 squared).

e.g. 250 kts IAS at 10,000 ft = 290kts IAS; at 25,000ft = 373kts IAS; at 40,000ft = 500kts IAS.

Wingswinger 27th August 2008 09:58

Crosswind
 
Crosswind rule:

Sine of the angle - 30 degrees off - 0.5
45 degrees off - 0.7
60 degrees off - 0.9

e.g. A 30 kt wind 30 degrees off the runway track is 15 kts across; 45 degrees off is 21 kts across; 60 degrees off is 27 kts across.

rubik101 27th August 2008 10:30

In 38 years of flying the only rule of thumb I have managed to learn and use is 3 times the height and around 10 miles to slow down from 250 kts.

Other than that, I think that unless you have a 8GB memory stick in your head, you will one day use one of these rules and forget whether it's times 2 or times 4 and is it the square or the square root?

Just learn to fly the aircraft and forget all these so called 'rules'.

l8starter 27th August 2008 11:06

Experience is everything,and there's lots of different experiences out there, but I suspect there are quite a few low hour guys out there who might feel they could benefit from this thread, and maybe others; you're never to old to learn, new information is stimulating, and my aging brain needs all the help it can get etc., etc.(I'm certainly a candidate for that !)

Just out of interest rubik,or anyone else, when ATC have left you high and you're decending with a 'good rate', and they ask you howmany track miles do you require, how do you come up with a (sensible) answer at short notice,because 3 x height may be a little over conservative in those circumstances ?

L8

kijangnim 27th August 2008 11:33

Greeting,
On the Airbus equipped with ISIS stadby instrument, Altitude divided by 3, well just look at your altitude in meters below 10000 ft read the first two digits of the meters, that your distance.....:ok:

Tight Slot 27th August 2008 11:36

On the A330 its more like 4 times the alt + 10 miles or so. It comes down like an empty crisp packet. (Potato chip packet if from the Western parts...) Massive wing with only 170ish tonnes, long way down...:)

kijangnim 27th August 2008 12:17

Greetings
Tight_slot
As you are on the 330,
above 10000 ft you take the 3 first digits of your altitude in meters to which you add the 2 first digits of your FL,
below 10000 you take the 2 first digits of your altitude in meters to which you add 10 :ok:

matthewgamm 27th August 2008 14:49

A320
 
Any thumb rules for the A320?

The Real Slim Shady 27th August 2008 15:32

Matthew

Yup.

Fly the 737 instead;)

HiFli 27th August 2008 16:01

The best substitute for brains is fuel.

fantom 27th August 2008 18:44

You are all wasting your lives if you don't fly 320/330.

I am thinking of setting up a charity for 73/5/6/ persons who need rules of thumb.

Poor bu**ers.

Cardinal 27th August 2008 19:17


Any thumb rules for the A320?
Put the hockey stick where you wish to be level :) Airmanship at its finest.

olepilot 27th August 2008 19:34


Any thumb rules for the A320?
Never ever turn down the wx radar intensity when you leave the flight deck!


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