JAA Question on Optimum Altitude
Okay, this JAA question was asked in 2001 on PPRune but no-one seemed to understand the question or terminology. I have been assured that answer A) is correct so in light of a further 7 years passing, are there any takers to explain?
For a long-range four-jet aircraft in cruising flight, the optimum altitude and the lock-on altitude increase. The most cost-effective flight plan will consist of choosing cruising levels which increase during the flight in order to fly:
A) about the optimum altitude
B) about the lock-on altitude
C) between the lock-on altitude and the optimum altitude
D) just below the optimum altitude