FAA Commercial Pilot Airplane (CAX)Aircraft SystemsHard
During a slow cabin pressurization leak, an airplane's cabin altitude climbs from 1,000 feet to 8,000 feet over a 4-minute period before the crew initiates an emergency descent. What was the average cabin rate of climb during this period?
- A2,000 feet per minute
- B1,750 feet per minute
- C1,400 feet per minute
- D875 feet per minute
Show answer & explanationAnswer & explanation
Correct answer: B. 1,750 feet per minute
The cabin altitude change is 8,000 − 1,000 = 7,000 feet over 4 minutes, giving 7,000 ÷ 4 = 1,750 feet per minute. This rate is well above the typical comfortable cabin climb rate (around 300-500 fpm) and would likely be noticed by passengers/crew as a rapid pressure change, prompting corrective action.
Why the other options are wrong
- A. This overestimates the rate; the correct division yields 1,750, not 2,000 fpm.
- C. This underestimates the total altitude change divided by the correct time.
- D. This would result from dividing by roughly 8 minutes, not the given 4 minutes.
Cabin Rate of Climb Calculation
Cabin rate of climb equals the change in cabin altitude divided by the time elapsed, similar to aircraft vertical speed calculations.
- Formula: (final cabin altitude − initial cabin altitude) ÷ time in minutes
- Normal comfortable cabin climb rates are typically 300-500 fpm
- Rapid or uncommanded high rates indicate a pressurization malfunction
Memory trick: Change in altitude over time equals rate.