Posted for "Gerard O Connell" <goconnell@dodo.com.au>:

 Hi guys, you may remember that some time ago I reported an unusual "buzzing"
noise from the fron of my 330 which I initially thought was engine related
then figured out it was airspeed related and most likely aerodynamic. The
culprit turned out to be a nose gear door not fully closing and thus "buzzing"
with higher IAS (>140kts).
 
 I have almost solved the problem having had the system re-wired and replaced
the pressure switches. It works perfectly well on the ground during retracts
however it appers to remain open for several minutes (not seconds) after take
off at which point the motor cycles very briefly and the door snaps shut. This
I can confirm by the gear transit light illuminating briefly and the "buzzing"
stops.
 
 My question is simple-is the spring mechanism which assists the closure
likely to be the culprit if it is not providing enough tension..yes I know the
answer is to replace it and see however I wondered if anyone has encountered a
similar problem and whether it might more or less likely be related to the
sequencing valve..as I said it only happens under airload.
 
 Any ideas guys?
 
 Thanks
 
 Gerard