This is where i get to read ya link given.
Its stated there.
Read it properly:
Minimum age 21 years at the time of application.
Minimum arm reach of 212 cms (on tip toes), which will enable you to reach emergency equipment on all aircraft types.
Educated to at least high school standard.
Medically fit to meet aircrew requirements.
Fluent in written and spoken English (fluency in another language is an asset).
Previous experience in the service/hospitality industry is an advantage.
Finally, you will be the sort of person who has the natural ability to provide excellent service within a team environment.
For ur info even if u're about to or not yet turn 21, i tell u wat,
dun waste your time. Trust me. U are just about the same age my fren. She's just about to reach 21 this yr but she get booted out becoz of her age. And they even told her bout they dun care even its counts by months or day or wateva. They wanna someone who already 21 yrs of age when u applying for tat post. Hope i do make myslf clear to u.
