Harmon Technologies, Inc.

Landing Gear Lever and Lights

The landing gear level controls the position of the landing gear.  It has two positions, up and down.  To change from one position to the other, the lever must be pulled out slightly and then moved.  This lock prevents accidental operation of the landing gear.  Although one should never count on it, a small switch (called the "squat switch") on the gear itself prevents retraction of the gear when the aircraft is on the ground.  N4907J also has an auto-extend feature that monitors the aircrafts speed and power settings and will automatically sound an alarm (a horn) and will even lower the gear automatically it it appears the airplane is operating in pre-landing configuration.  As the plane is slowed, the system will occasionally sound the horn just before the pilot decides to lower the gear.  This horn does not indicate a problem or safety concern.  (There are many cockpit alerts and noises that are routine).

The yellow light flashes when the pilot has disabled the auto-extend system (this is appropriate when performing certain manuvers as well as when doing maximum performance (short runway) takeoffs.  There is also a red light elsewhere on the panel that shows when the gear is in transit.  The three green lights show that each wheel is in the "locked down" position.  When the gear is up, no lights will be on.  A red light (in front of the pilot) indicates that the gear position is in transit or does not agree with the lever setting.  Three green lights indicate a normal gear down condition.  It is traditional to check for three green lights during the approach and again just before touching down.  Passengers are encouraged to double check for three green as well when on final approach. 

The auto-extend system makes a gear-up landing unlikely.  (We should also note that while gear up landings are not good for airplanes, they are not generally hazardous to passengers). 

We should also note that there is a backup emergency gear extension system that allows the gear to free-fall because of gravity (and some springs for additional assistance).  This will operate even if the electrical and hydraulic systems fail!  The lever for emergency extension is located between the front seats.

Copyright © 2004 Harmon Technologies, Inc.