FAA Instrument Rating Airplane (IRA)IFR Procedures and ChartsHard
An Obstacle Departure Procedure (ODP) requires a climb gradient of 290 feet per nautical mile to 5,000 feet MSL. The pilot plans to fly the departure at a groundspeed of 140 knots. What minimum rate of climb, in feet per minute, must the pilot maintain to comply with this requirement?
- A580 feet per minute
- B677 feet per minute
- C812 feet per minute
- D406 feet per minute
Show answer & explanationAnswer & explanation
Correct answer: B. 677 feet per minute
Required climb rate (fpm) = climb gradient (ft/NM) × groundspeed (kt) ÷ 60. Calculation: 290 × 140 ÷ 60 = 40,600 ÷ 60 ≈ 677 feet per minute.
Why the other options are wrong
- A. This underestimates the required climb rate for the given groundspeed.
- C. This overestimates the climb rate; check the division by 60 for minutes conversion.
- D. This value results from an incorrect groundspeed or gradient figure in the calculation.
Climb Gradient to Climb Rate Conversion
A method to convert a published climb gradient (ft/NM) into a required rate of climb (fpm) based on groundspeed, ensuring obstacle clearance during a departure procedure.
- Formula: Rate of climb (fpm) = gradient (ft/NM) × groundspeed (kt) ÷ 60
- Higher groundspeed requires a higher climb rate for the same gradient
- Climb gradient tables in the front of approach plate books simplify this conversion
- ODPs specify the minimum climb gradient needed to clear obstacles
Memory trick: Gradient times speed, divide by sixty — get your climb rate quickly.