>Jethro wrote:

>> On 5 Jun, 11:02, Doh microsoft.com> wrote:

>>> cupra wrote:

>>>> Enzo Matrix wrote:

>>>>> Mel Rowing wrote:

>>>>>> On 4 Jun, 22:41, allan tracy hotmail.com> wrote:

>>>>>>> He was just about to pull the gear up lever (the wheels) when they
>>>>>>> finally noticed him.

>>>>>> You can't raise or lower the landing gear unless the hydraulic pumps
>>>>>> are operating.
>>>>>> Perhaps they left the engines running too!

>>>>> There is also a circuit that routes through a microswitch on the
>>>>> undercarriage. If there is weight on the wheels, the circuit will be
>>>>> broken and the undercarriage cannot be retracted. Only when the
>>>>> aircraft is airborne is the circuit completed, allowing retraction to
>>>>> commence.
>>>>> Some military pilots will select "wheels up", before commencing their
>>>>> take-off roll, so that as soon as the aircraft lifts off, the gear
>>>>> comes up. It's a bit dangerous to do so though, as a bumpy runway can
>>>>> cause the aircraft to bounce slightly before flying speed has been
>>>>> attained, leading to the aircraft settling back on its belly.

>>>> Haven't they heard of hysteresis then?

>>> Is that where people get all excited for no good reason?- Hide quoted text -

>>
>> No, you;re thinking of historics.
>>

>Nah, thats when a woman has her undercarriage removed!