Your airplane just came out of maintenance. You picked the best, most qualified shop to do the work, and now you’re excited to get in the air again. You jump in, fire up and launch into the sky. Then you realize something is not quite right.
Unfortunately, this happens all too often. Picking up an aircraft from maintenance is one of the more challenging and dangerous flights you can make. We expect everything to be perfect, and that’s not always the case. Mechanics are human and occasionally make mistakes just like pilots do. In the flying game, mistakes can turn deadly very quickly. What can we do to reduce our chances of having an incident or accident?
The first thing you can do is schedule more time than you think it will take. It is not uncommon to find multiple squawks coming out of maintenance. It’s great when we don’t but give yourself time should the airplane not be perfect the first time you look at it.
Next, assume everything has been changed in the plane, from friction locks to trim positions, flap settings, seat position, etc. Check everything, even if it was not part of what was worked on; it might have been bumped or changed accidentally.
After that, pull out the factory checklist and go through the factory preflight line by line. Yes this will take time, and yes you still need to do it.
What are some items that need a little extra attention during your preflight? Starting at the cabin door:
The door seal: Pay close attention to the inflation tube at the base of the door as well as the top of the door frame. Passengers kick or drag bags across it frequently.
Flaps: When they are retracted, they should have a small amount of play in them. If they are tight, they will need to be adjusted.
Exhaust stacks: Give them a knock with your knuckle, listen to the sound and learn what each sounds like. If a crack develops the sound will change.
Nacelle cowlings: The top forward cowl is held down by a cam system. Occasionally the cam does not engage the hook side to snug and hold the cowl down. Give the cowl a thump in an upward motion with the heel of your hand to make sure it is secure. If your paint scheme has stripes that flow over the nacelle it is easy to see when the stripes don’t line up. If you do have a cowl come loose during flight, open the ice vanes and it will help suck the cowl back down until you land.
Nose gear: There are two things to check here. Make sure the stop block on the aft portion of the strut is straight. If your plane was towed and the turn limits exceeded, it will be bent and will need to be checked out by a mechanic. The other item that should be checked is the shock link spring clip. If this clip fails and falls out, the spring in the shock link will expand and push your nose wheel into a right turn. You will not be able to use your rudder pedals to straighten out the airplane.
Control surfaces: If your plane is coming out of the paint shop, pay extra attention to control surfaces as they were removed for painting. Check all your required placards. The complete list can be found in your aircraft’s POH. On the C90 series and E90 aircraft, check the trim markings on your elevator.
The static ports: Check your static ports on both sides of the fuselage. We have seen and had reports of tape being left covering the ports after paint or after getting washed.
Congratulations, you have completed the interior and exterior preflight without finding any issues! Now is the time to start up, taxi to the runup area and perform a full runup. You were going to execute the full runup, right?
Before you start, complete the fuel panel test if you haven’t already. It can be accomplished with just battery power and is quick to do. It is not uncommon to find firewall valves that stick open or do not seal properly.
Things to look for during runup:
Minimum prop RPM: For all 4-bladed props on King Airs there is a minimum prop RPM. Make sure you are idling above the appropriate number for your aircraft. If you are below that limit you could experience reactionless vibration (the prop blades flexing in opposite directions without being felt in the airplane). This will damage your prop hub and require prop and blade replacement.
Overspeed governor check: When performing this check, there are two things to watch for: (1) Move the test switch into the test position while your prop is under the test RPM for your prop. If your prop RPM is above the test RPM setting it will come down very quickly! (2) Ensure the prop is in the proper RPM range.
Autofeather check: Pay close attention to the torque reading when the autofeather lights illuminate. Remember, the 400 ft-lb and 200 ft-lb sensors are not as accurate as your torque gauge. It is not uncommon to see the autofeather lights illuminate as high as 500 ft-lbs. Watch when the opposite autofeather light extinguishes as power is reduced. The autofeather system has proven to be very reliable but make sure it is working the way it’s supposed to.
Rudder boost: This will take lots of power to activate on the ground. On a hot, high-density altitude day it might be impossible to check activation without exceeding engine limitations.
Pressurization test: The most common mistake seen here is not opening the bleed valves. Moving your condition levers to high idle will speed up the test. Remember to confirm the test switch is back in the PRESS position after completing the test.
You should have done this already during the interior preflight, but here is another chance to verify your trim settings and friction locks. Some King Airs are known to have power lever migration issues. If this happens during takeoff, the lack of speed and altitude makes it difficult to recover. Look at accidents in Wichita, Tucson and Addison as examples of possible PLM-related accidents. Unfortunately, the post-accident fire destroys evidence of PLM but all three have hallmarks of it occurring just after takeoff.
The first flight when picking up an aircraft from maintenance will always be challenging. Make the flight as safe as you can by being thorough in your preflight and runup.