Which statement correctly pairs AHRS initialization times on ground and in flight?

Which statement correctly pairs AHRS initialization times on ground and in flight?

• A. Ground 70 seconds; Flight 10-35 seconds
• B. Ground 10-20 seconds; Flight 70 seconds
• C. Ground 60 seconds; Flight 5-15 seconds
• D. Ground 5 minutes; Flight 1 minute

Answer: (A)

AHRS initialization time depends on whether the aircraft is stationary on the ground or moving in flight. On the ground, the system must establish all reference vectors with no motion to aid the alignment, so the process tends to take longer—around 70 seconds. In flight, the AHRS can use the aircraft’s actual motion and known attitudes to complete the alignment more quickly, typically in the 10–35 second range. The option that matches these real-world timings is ground about 70 seconds and in-flight about 10–35 seconds. The other pairings describe times that don’t line up with how in-flight motion speeds up alignment or with how ground alignment tends to be longer.

AHRS initialization time depends on whether the aircraft is stationary on the ground or moving in flight. On the ground, the system must establish all reference vectors with no motion to aid the alignment, so the process tends to take longer—around 70 seconds. In flight, the AHRS can use the aircraft’s actual motion and known attitudes to complete the alignment more quickly, typically in the 10–35 second range. The option that matches these real-world timings is ground about 70 seconds and in-flight about 10–35 seconds. The other pairings describe times that don’t line up with how in-flight motion speeds up alignment or with how ground alignment tends to be longer.