Nose gear centering
As Backpacker says the final inch or so of nose gear extension results in the nose gear centering lock engaging and locking the nose gear steering in the Neutral position. If this should happen at low speed the aircraft is almost imposable to steer as there is not enough rudder authority to overcome a well planted and unsteerable nose wheel.
This situation is a result of a lack of or bad maintenance practices and will not occor in a well maintained aircraft.
Unlike American aircraft Robin landing gear legs require a measured amount of oil, American practice is usually to fill the compressed leg with oil and then compressed air, the Robin leg requires to be overfilled ( in American terms ). This oil quantity is critical along with the correct air pressure to obtain the correct rising spring rate when the leg is in service.
I have seen nose legs over inflated presumably to increase the propellor clearance and main legs under inflated ( for a softer ride?) but both of these defects are an accident going some place to happen as premature nose gear centering lock engagement is likely to occor.
The later DR400 maintenance manuals offer very clear guidance on the servicing of landing gear legs ( the first edition of the manual was a less than understandable translation from the French language ).
The maintenance data is different for all the DR400 variants and should be strictly adhered to to obtain the correct Spring rate for that DR400 variant, of this is not done there is a danger of the nose gear steering locking.
The technique I described in a post above is intended to keep some of the weight off the nose gear but not to have it pointed skywards, initially on the takeoff run the thrust vector ( the only vector at the start of the takeoff ) is trying to dig the nose gear into the ground and full up elevator counters this and keeps the aircraft in a level attitude, as the aircraft gathers speed and elevator authority increases the stick should be moved forward towards slightly aft of neutral to maintain this attitude until about 50 KTS when a smooth rotation should start aiming to lift the main wheels off the ground at 55 to 60 KTS.
Keeping the stick hard back throughout the take off run is going to end in tears, the aircraft is more than capable of getting off the ground well below normal stalling speed and therefore without full control authority due to ground effect...........it is an interesting flight regime that is best left untried by all but test pilots.