Flyboy, I am afraid that the 4 year figure that you quote is totally wrong.
You need to have 44 years of qualifying payments to get the full state pension, you have 5 years of grace ie 5 years you can miss payments on and there are circumstances where you do not have to pay the short fall - looking after children is one.
It is a minor thing to do with CTC anyway, but it is relevant to anyone going through flight training whilst not working.
S
From the Inland Revenue
What is a qualifying year?
The amount of basic State Pension you will receive when
you reach State Pension age depends on the number of
years you have paid, or been treated as paying, National
Insurance contributions. These are called ’qualifying years’.
Sometimes you can be credited with National Insurance
contributions when you are unable to do paid work.
You need to have paid, been treated as having paid or
been credited with, enough National Insurance
contributions to get a qualifying year.
The number of qualifying years you have determines the
amount of your basic State Pension. At the moment, there
are different requirements for men and women. State
Pension age for women will change between 2010 and
2020. So, the number of qualifying years for a full basic
State Pension a woman needs will gradually increase
to 44 years, the same as a man.
Some people do not get a full basic State Pension because
they do not have enough qualifying years. If you retire
with less than a quarter (25%) of the qualifying years for
a full basic State Pension (currently 11 years for a man and
10 for a woman), you won’t get any basic State Pension
based on your own record, although you could on your
spouse’s record.