Applicants seeking an instrument rating or ATP certificate may find these useful.
Calculating Va: (maneuvering speed)
Sqrt of (TOW / MGTOW) * published Va (162mph)
Example:
Actual weight: 24000 lbs. MGTOW: 28,000 lbs
Sqrt of 24000/28000 = 0.926 * 193 (published Va) = 178.68
Calculating lead intercepts for DME arcs and any selected course
TAS / 200
Example:
200KTAS / 200 = 1.0
Therefore, initiate a standard rate turn 1.0nm prior to arriving at the arc.
For a 45 degree intercept to the final approach course, 0.5nm (use FMS/GPS for XTRK information.)
For a 30 degree intercept, initiate at 0.2nm.
Calculating Rate of Descent to track glideslope
(Groundspeed / 60) * 300
Example:
135 knots GS
135/60 = 2.25
2.25 * 300 = 675 FPM
Note: 300 is used because flying a 3-degree glideslope will cause the aircraft to descend 300 feet per nautical mile (FPNM.) If a nonstandard glideslope angle is published on the IAP, use that number instead (i.e. if 3.24 degrees, use 324.)
Alternate method:
Ground speed X 5 = VS to maintain
(Faster to calculate 10 X ground speed / 2 = VS)
Example: 120 KT x 10 = 1200
1200 / 2 = 600 FPM
Alternate method (rule of thumb):
Use 10% of groundspeed, and multiply times 5.
Example:
140 knots GS 140 * 5 = 700FPM
This method is quite accurate, provided a standard 3.00 degree glideslope.
Initiating level-off from climb or descent
10% of Rate of Climb/Descent
Example:
If climbing at 500FPM, initiate level-off 50 feet below target altitude.
Calculating bank angles for standard rate turns
10% of TAS / 1⁄2 of that number
Example:
120KTAS 12 + 6 = 18 degrees angle of bank
Calculating roll-out from steep (45 degree bank angle) turns
Initiate roll-out at a heading equivalent to 1⁄2 the bank angle.
Example:
45 degree bank
Turn initiated at 360 degrees to the left
Initiate rollout at (45 / 2) 22.5 degrees prior to reaching 360, i.e. 023 degrees.
Calculating VDP (or PDP, Planned Descent Point)
Distance-based VDP/PDP:
MDA (HAT) / 300
Example:
MDA is 430 ft. AGL. 430/300 = 1.4nm
Time-based VDP/PDP:
Subtract 10% of the MDA (HAT) from the time between FAF and MAP
Example:
MDA is 430 ft. AGL
Time between FAF and MAP is 3:54
10% of 430 = 43
Subtract 43 seconds from 3:54 = 3:11 to VDP/PDP
How far out to start a descent? (3° glide)
Altitude to lose / 300
Example: 6000’ to lose, start descent 20 NM out.
(6000/300 = 20 NM)
Convert climb gradient from ft/NM to FPM
Ft/nm requirement x NM per minute
Example: DP requires 300 ft/NM climb.
Your ground speed is 120KT, which is 2NM per minute (120 KT / 60 min = 2 NM per minute).
300 x 2 = 600 FPM