In a message dated 14/11/2006 10:20:40 GMT Standard Time, bones@xxxxxxx writes: Transition Level won't be a variable because it varies from country to country and can vary within areas within a country (like the UK). If you are flying any posh aircraft with built in altitude alert - the one that dings at you as you approach 1000ft to go to target altitude - a crafty dodge is to dial in 1000ft above TA rather than your cleared level. When it dongs reset altimeters to 1013.25 and dial in your cleared level. bones Er, if it were a variable then presumably one could change it, unlike the constant it appears to be? My planned gauge would warn the pilot as TL was hit in either direction, up or down. Frank T.