Folks.
I am working on a desk reference document that will include (as a very small part) a list of useful rules of thumb. By this I mean ones you can actually use or may find interesting. To this end I have compiled the following list. Who has others they actually use? Please feel free to add to the list of correct the ones i have. I am only interested in ones that will be relevant to RAAus type operations so won't need to find the Null in an ADF or know the crossing distance when overhead a DME or work out angle of bank for rate one turns etc etc....
General
· ONUS Overshoot North Undershoot South
· SAND Apparent turn to South when Accelerating and North when Decelerating
· Variation East magnetic least, Variation West magnetic best
· The air is conditionally unstable if the temperature drops more than 2° per 1,000 feet on ascent
· If the wind differs from the runway heading by 15 degrees, the crosswind component is 25% of the wind velocity. If the difference is 30 degrees, the crosswind is half of the reported wind speed. If the difference is 45-degrees the crosswind component is 75% of the overall wind speed. If the difference is 60 degrees or more assume the crosswind is the same as the total wind.
Take Off Performance
· A 1°C change in temperature from ISA will increase or decrease the takeoff ground roll by 10%.
· Takeoff distance increases by 15% for each 1000′ DA (Density Altitude) above sea level
· A headwind of 10% takeoff speed will reduce ground roll by 20%
· A 10% change in aircraft weight will result in a 20% change in takeoff distance.
· The maximum crosswind component is approximately equal to 0.2 x Vs1
· Abort the takeoff if 70% of takeoff speed is not reached within 50% of the available runway.
· Available engine horsepower decreases 3% for each 1000’ of altitude above sea level.
· Fixed Pitch, Non turbo aircraft - Climb performance decreases 8% for each 1000’ DA above sea level.
· TAS increase 2% for each 1000’ in a climb.
· Standard temperature decreases 2° for each 1000’
Approach & Landing
· A 10% change in airspeed will cause a 20% change in stopping distance.
· A narrow runway may give the appearance of being longer, a wide runway may give the appearance of being short.
· A slippery or wet runway may increase your landing distance by 50%.
· Use Vso x 1.3 (Vref) for approach speed over the threshold.
· Plan to touchdown in the first ⅓ of the runway or go around.
· For each knot of airspeed above Vref, the touchdown point will be 30m further down the runway.
· For each 1000’ increase in field elevation above Sea Level, stopping distance increases by 4%.
Flight Manoeuvres
· Use ½ the bank angle for the lead roll out heading.
i.e 30° of bank angle Start roll out 15° before desired heading.
· To make a 6° change in heading, use a standard rate turn then immediately level the wings. To make a 3° change in heading use ½ standard rate turn.
· Maneuvering speed Va = 1.7 x Vs1
· Va decreases 1% for each 2% reduction in weight
· Vy decreases ½ to 1kt for each 1000’ DA
· Vy Vx and Vg (best glide) decrease ½ kt for each 100lbs (45KG) under MGW
· Vr = 1.15 x Vs
· TAS = IAS (kts) + FL/2
eg:
FL 300, IAS = 240
TAS = 240 + 150 = 390 Kts
· Best Cruise climb speed is the difference between Vx and Vy and add this to Vy.
Eg Vx = 65, Vy 75
Difference is 10kts
10kts + Vy 75 =85Kts
Climb Planning
· Add 1 minute to your flight plan ETE for every 1000′ climb to cruise altitude.
Cruise altitude = 8000′ Time to add = 8 mins to ETE
· To find the Rate of Climb required (ROC) multiply the % gradient by the groundspeed.
% Gradient = 3.3%
Groundspeed = 120 Kts
3.3 x 120 = 400fpm
· To find the Feet per Minute (FPM), multiply the gradient % by 60
3.3 % Gradient x 60
= 200 fpm
Descent Planning
· One degree climb or descent angle closely equals 100’/ Nm.
· To determine the NM distance to start a 3° enroute descent.
Divide the altitude to lose ( in Flight Levels) by 3.
e.g.
Altitude to lose = 6,000 (FL 60)
60 / 3 = 20 nm to start descent
· For a 3° Rate of Descent (ROD) take half your groundspeed and add a zero.
Descent Groundspeed.
120 x ½ = 60
600 fpm ROD