People – thanks for the replies. I should say that this came from a discussion over a drink and is not a question how to operate – the SOPs tell me that and I follow them.
Jumbo – thanks for posting the correct text my recollection was basically correct in that it says “vertical position will be expressed in terms of flight level” after being cleared to a flight level. However I find your comment:
“in any event, you will/should always have a second or stand-by altimeter set to QNH during the climb and descent so that you can reference any request to altitude, if 1013 is already (or remains) set.”
a little bit arrogant because you do not know what my SOPs say. Basically in the type I fly we have 2 main altimeters and 1 standby. The standby is ALWAYS set to 1013mb and the mains adjusted as we climb in accordance with SOPs (both mains are always sets the same).
So if we were to go to 1013mb when cleared to a flight level then we would have no altimeter set to QNH should ATC wish to stop our climb at an altitude. By keeping the main altimeters on QNH we can “express our vertical position in terms of FL” by reading off the standby AND stop the climb at any altitude as required.
A colleague of mine (in another airline) started this discussion by stating that once we were cleared to a flight level then ATC will expect all vertical positions to be referenced in flight levels – including any subsequent “stop climb” instructions – even if below the transition altitude. Hence this posting for the opinion of ATC from the UK and preferably in the London TMA as this has the 6,000ft transition.
Cheers HP
Ps BOAC sorry I’ve no idea what you are referring to with “3 down”. If that means “slow learner” then guilty as charged.
