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JOINT ADVANCED MULTIENGINE T44A
G. Summary of the 60to1 Rule and Other Rules & Formulas:
1.
What is the 60to1 Rule and Why Should You Use It? It is a technique for establishing
predictable pitch changes for climbs or descents and lead points for intercepting courses or arcs.
The following are three good reasons to use this rule:
·
It allows the pilot to compute the pitch changes necessary when establishing an attitude
during the control and performance concept of attitude instrument flying discussed in the BI
stage.
·
It reduces the pilot's workload and increases efficiency by requiring fewer changes and less
guesswork.
·
It is an alternative to the TLAR (That Looks About Right) method of flying. After gaining
experience using the 60to1 rule, it will improve your TLAR accuracy.
How to Work With the 60to1 Rule. The 60to1 rule gives us a mathematical equation to help you
figure out all these questions, but it is almost impossible to run these calculations and fly at the same
time. You need to use the formulas before you fly. Find out what your turn radius is at cruise airspeed
up high and at approach airspeed down lower; find out what a 1° pitch change will do to your VVI and
remember those numbers.
The 60to1 Rule:
1° = 1 NM at 60 NM(60 NM from the station, there is 1 NM between each radial)
1° = 100 FT at 1 NM(1° climb or descent gradient results in 100 FT/NM)
VSI Versus Pitch Change. We now know how to calculate the altitude gained or lost for each degree
of pitch change over a given distance. Throw in a time factor using True Airspeed (TAS) expressed in
NM per MIN and we can relate this pitch change to a change in VSI.
·
First, lets convert speed to NM/MIN, since the 60to1 rule is based on TAS expressed in
NM/MIN. NM/MIN can be obtained easily from TAS as follows:
2.
NM/MIN = TAS/60
Examples: 120 KTAS = 2 NM/MIN
150 KTAS = 2.5 NM/MIN
·
Since we don't have a TAS indicator, TAS can be computed from IAS. TAS increases over
IAS at the rate of 2% per 1,000 feet altitude increase. So, the following equation could be
used:
TAS = IAS + (2% per 1,000 FT) X (IAS)
Example: 3,000 FT; 150 KIAS
TAS = 150 + (2% X 3) (150) = 150 + (.06)(150) = 159 KTAS
·
Another easy but less accurate rule of thumb (best used above 10,000 feet) to determine TAS
is:
or
"Add 5 kts per 1,000' to IAS"
TAS = IAS + (FL/2)
Example: FL 200; 175 KIAS
TAS = 175 + (200/2) = 275 KTAS
·
If one degree equals 100 ft/nm, then our VSI can be calculated numerous ways:
VSI for 1° pitch change = NM/MIN X 100 FT
VSI = (Pitch Angle) X (NM/MIN X 100)
VSI = (Gradient) X (NM/MIN) = (FT/NM) X (NM/MIN)
RADIO INSTRUMENTS STAGE
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