Emergency, urgency (PAN PAN)

Mode C Failure / Altimeter Redundancy, RVSM Non-Compliant

4 turns, word for word from the oral. Read the pilot lines out loud.

The exchange

4 turns in order
01
You, the pilot

Varanasi Control IFLY 160, 40 NM inbound BBN, transponder Mode C is failed, aircraft RVSM non-compliant, request descent to FL 270

02
You, the pilot

OR: Varanasi Control IFLY 160, 40 NM inbound BBN, altimeter system unreliable, aircraft RVSM non-compliant, request descent to FL 270

03
ATC

VT ROH, leave ATS route, descent FL 270, passing FL 290 resume normal navigation

04
You, the pilot

Leaving FL 350 for FL 270, turning left to leave ATS route, descent FL 270, passing FL 290 will resume normal navigation