Just to make this clear, here's the applicable booking rules from the fare rules, as on travel.com.au (incidently I came across a case this week where those rules on there were *** WRONG *** - don't panic, it was for a fare involving * carriers..).
Anyway, the T class fare:
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">
ECONOMY: T (BA - LONGHAUL 'WORLD TRAVELLER PLUS'
SECTORS);
ECONOMY: H (BA - LONGHAUL SECTORS WHERE 'WORLD
TRAVELLER PLUS' CLASS IS N O T
OFFERED);
ECONOMY: B (BA - INTRA EUROPE SECTORS IN 'STANDARD'
ECONOMY/SEAT CLASS A N D UK
DOMESTIC SECTORS O N L Y);
ECONOMY: H (QF - TRAVEL IN 'STANDARD' ECONOMY CLASS
CABIN ONLY);
ECONOMY: Q (BD - BETWEEN LON AND BFS O N L Y);
ECONOMY: B (CX - *BETWEEN PER AND HKG O N L Y FOR
TRAVEL TO 31MAR04 O N L Y)
</font>
And the W class:
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">
ECONOMY: W (BA - LONGHAUL 'WORLD TRAVELLER PLUS'
SECTORS);
ECONOMY: H (BA - INTERCONTINENTAL LONGHAUL SECTORS
IN 'STANDARD' ECONOMY/SEAT CLASS
WHERE 'WORLD TRAVELLER'CLASS IS
NOT AVAILABLE);
ECONOMY: Y (BA - INTRA EUROPE SECTORS IN 'STANDARD'
ECONOMY/SEAT CLASS A N D UK
DOMESTIC SECTORS O N L Y);
ECONOMY: H (QF - TRAVEL IN 'STANDARD' ECONOMY CLASS
CABIN ONLY);
ECONOMY: Q (BD - BETWEEN LON AND BFS ONLY);
ECONOMY: Y (CX - *BETWEEN PER AND HKG O N L Y FOR
TRAVEL TO 31MAR04 O N L Y IN
STANDARD ECONOMY SEAT)
</font>
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RichardMEL, UA 1K
A Star Alliance Member.