Systems Refresher-Landing Gear Extension

by Sam Swift

OK, now that it's warming up all over the country, many of us are digging our Swifts out of hibernation and getting ready for the flying season. Not only must our Swifts be ready to fly, so too must we. If it's been a while since your Swift has flown much, now is a great time to clear out the cobwebs from our systems knowledge of our Swift.

The landing gear of our Swift is perhaps the most complex system on the airplane. If I asked, "How many ways are there to get the gear down?" what would you say? (Cue the music from Jeopardy)... Two, you say? WRONG! Try again....three? Yes, there are actually three ways to get our feet down and locked in the Swift to prevent the embarrassing short-field slide down the runway.

Remember, the Swift has electro-hydraulic gear with an emergency manual gear extension cable. Now think about this for a minute as we dissect the gear system.
"electro-" the gear has an electrical switch on the backside of the instrument panel that is physically moved when you rotate the gear handle. That switch energizes the hydraulic pump on the firewall and causes hydraulic pressure to be built up. Hmmm...
"-hydraulic" the gear is extended or retracted by the force of the hydraulic fluid flowing through its respective valves. These valves are located on the firewall (in that box beneath the hydraulic pump) and opened when you rotate the gear handle to the UP or DOWN position.

Lets say are on the downwind leg of your favorite pancake fly-in and reach down for the gear handle, but nothing happens. No hydraulic motor noise, no wind noise from gear extending, yawing of the plane, nothing. What just happened here? Why isn't our gear coming down? Ok, time to either crank the gear down or use an "alternative" method. Remember that switch referenced a couple of paragraphs ago that is behind the panel? In our example today, that switch just failed and no longer works (hydraulic pump on the firewall is fine and the flap system works fine); therefore, when you rotate the gear handle to the DOWN position, you did move the valves in the right position, but the hydraulic motor never comes on to push the gear down. All you need is some hydraulic pressure to force those Michelins to their proper place! Where else can you get some hydraulic pressure? Do you see where I'm going with this? Remember, the flaps use the same hydraulic motor. Why not cycle the flaps (with the gear handle down)? Yes, it works just fine, thank you. So long as you are not above 90mph (Vfe-max flap extension speed) you can cycle the flaps a few times (my Swift takes around 3 cycles) and that will turn the hydraulic pump on and extend the gear. Be careful as you will get a lot of speed/pitch changes going from zero to full flap so don't get distracted!

OK, in the next example we figure out that our hydraulic pump isn't working (let's say the hydraulic fluid all leaked, a hydraulic line broke, etc.). We know that trying to utilize the flap system to force the gear down won't work, since they are hydraulic, too. Now we proceed to the emergency gear extension method. Some of these steps might be a bit different for your Swift, depending on how (or if) your instrument panel has been modified with switches and breakers, but here goes:
(1) Put the Landing Gear Handle to the DOWN position,
(2) Pull (or turn OFF) the Landing Gear circuit breaker (or switch)
(3) Pull (or turn OFF) the Hydraulic Pump circuit breaker (or switch)
(4) Using the Emergency Gear Extension handcrank between the seats, turn the handle clockwise 50-52 turns. (CAUTION-do not overcrank the handle as damage can result in binding of the internal tension spring).
(5) Push (or turn ON) the Landing Gear circuit breaker to see that you now have a GREEN indication for your landing gear (with no RED).
(6) Pull (or turn OFF) the Landing Gear circuit breaker after confirming the gear is down and locked. (Note-turning this back off ensures that power is not restored to the normal gear retraction/extension system. Once you've used the emergency system, there is no need to risk the system fighting itself should it all of a sudden start working again.)
(7) Land

After landing and prior to the next flight it is imperative that the Emergency Gear Extension handcrank be unwound (counter-clockwise) the same number of turns (50-52) that it took to extend the gear. Failure to do so will result in significant damage to the wing centersection !

All that being said, we've reviewed the following three ways to get the gear down,
(1) Normal method with gear handle,
(2) use the flaps to get the gear down, and
(3) emergency gear crank.

Please try to keep these in the back of your mind so you're not the one to make the next slide down the runway! Fly Safe!