Question: Are there situations in which a pilot could/has to lower the landing gear during flight for reasons not directly connected to landing? (i.e., not part of the landing checklist)

Originally I thought I had seen some around the location indicated by the pin on the map below (17° 25' 30.093" N, 78° 32' 27.4734" E), in the evening time around 4:00 and the weather was clear.

[![Sighting location](https://i.stack.imgur.com/78nOO.jpg)](https://i.stack.imgur.com/78nOO.jpg)

Answer: 
Landing gears are generally retracted to decrease drag in flight . As the speed of 
an aircraft increases, so does parasite drag. Mechanisms to retract and stow the landing gear to eliminate parasite drag add weight to the aircraft. 

Private Jets generally use Tricycle-type landing gear with dual main wheels . One of the main advantages of using the Tricycle-type landing gear is that it prevents ground-looping of the aircraft. Since the aircraft center of gravity is forward of the main gear, forces acting on the center of gravity tend to keep the aircraft moving forward rather than looping, such as with a tail wheel-type landing gear.

It is not necessary to retract the landing gear . Infact there are Landing gears that are Fixed as can be seen in many small, single engine , light aircrafts . 

On certain occasions Private jets as well as large aircrafts like the Boeing 777 extend their landing gear during flight **to cool the Brakes** because :

1. *The brakes may have been heated by the previous landing and not had time to cool while the airplane was at the gate*.
2. *During taxi out, they were further heated by necessary brake applications*.
3. *After takeoff, the landing gear retracted into the wheel well where there is limited cooling air*.
I cannot imagine much need to lower the gear during flight, except perhaps if there was an issue. Also doing so mid flight would required restricting speed to the lower of Vlo (landing gear operating speed) or Vle (landing gear extended speed).

The actions that one takes that involve dropping the gear are usually part of some error handling procedure. These may be documented in operational manual or be something defined during training on the specific aircraft.

The one time I dropped gear in flight it was after one of the gear lights failed to turn off (indicating gear up and stowed) after retract. I slowed up to stay within the operational limits, dropped the gear and then retracted the gear. This time the gear light stayed off. After landing I checked the gear switches for a stuck piston or loose wire. I did not find anything and the problem never repeated.

If the problem had been something like a gear motor circuit breaker popping I would have reset the breaker ONCE. If the breaker popped again I would have cranked the gear down and left it down.