Originally Posted by
RAT 5
If the 737 can do it below 10ft RA,
On the B732 version I flew there was a squat switch on the nose gear to prevent this. I don't know if it was a company option or standard. It seemed a good idea, because on bucket reversers ground contact as the a/c reared onto its haunches was a real threat; there-after the tail.
Original 737s had clamshell reversers with short nacelles like 727. These proved ineffective as the reverse airstream was directed under the wing & actually took weight off the wheels. About 1970, Boeing came out with the "target type" reverser that extended the nacelle to put the reversers behind the wing trailing edge. This mod included squat switches on main & nose gear so reversers were inop until all wheels on ground. Switches were provided on overhead panel to overide the squat switches & still get reverse in event of switch malfunction. After about 10 yrs (1980?), it was realized that the nose gear switch was not needed & it was removed. This is because opening the reversers imparts such a strong nose-down pitching moment that reverser ground contact is no problem & it enables reverse immediately at main gear touchdown where it is most effective. As previously stated, the 300 & subsequent models use 10' ra to enable reverse instead of the squat switch, but I never heard of opening them prior to touchdown.