There is no condradiction at all
It is just our common sense which refuse to accept this claim

Clocks are alwayes non syncronized even when B is on flight

Suppose that B is travelling at 50 % of speed light
A and B can comunicate via radio msg's

A says

" You must reach waypoint P(x,y,z) at time T "
if B take the figures as they are he will miss the target
He must turn the figures into his " B's time / space frame "
Not only
If A says
"You must reach waypoint P(x,y,z)"

To us it makes sense but not for the pilot
B would not know where to go to

A must comunicate also the Time !

In the theory of relativity time and space can not be split

The concept of "contemporaneity" has been banned
It does not make any sense to claim

" If the time on earth is...then the time on board..."

The famous equation

Tb = K Ta

with k = 1/sqrt((1 - (v/c)^2)

it does not give the time on board (tb) given the time on the earth(Ta), as many people assume
Tb is the time on board in the " A's space/time frame "

The only thing in common between A and B is the so called "Interval" which is a mix of space and time

I = SQRT(T^2 -L^2) the formula contains also the light speed "c"

If you still think that "turning" is the solution, borrow 3 syncronyzed atomic clocks
One in Berlin, one In Hamburg, one for you
Buy a one way ticket
You will see that your own atomic clock will be some milli seconds late

P.S

Many years ago I made an animation in visula basic 6.0 , using the simple equations of the special relativity, to show how the two observers, in relative motion, describe the same event : an explosion of a super nova
It is rather easy to create but it was quite interesting , at least for those strange guys who are interested in such stuff