Hi Irish Steve,
I agree that the phrases using "maintain" are unambiguous but so would omitting the word "to", i.e. descend Flight Level 330, climb altitude 3000 feet.
I'm afraid I always find the phrase "maintain" irritating though since if I give a clearance why would the pilot do anything other than maintain the level on reaching !!
Probably due to the education I received in grammar and english, it also grates me when it is used as an instruction, mostly heard in the US, e.g "maintain FL330". This being given to get the aircraft to climb or descend from it's present level to that new level. Maintain to me implies keeping the status quo, i.e. your current level !! But then the UK and the USA are two nations separated by a common language
In fact this latter point was the cause of an Airprox last year with (I think from memory) a US corporate jet over the North Sea. The aircraft was at (for example) FL330 but the controller misread the strip and on it's first call the pilot was instructed to "maintain FL370" which was it's filed cruise level. Of course the pilot then took that as a clearance to climb and clanged with somebody in the intervening level.
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10 West
UK ATC'er
[email protected] ICQ 18043595
[This message has been edited by 10W (edited 17 June 1999).]