I’ve been getting a few calls lately about “the wing AD.” King Air owners want to know: Do I have to do it? And if so, where should I go? They are referring to the Federal Aviation Administration’s (FAA) Airworthiness Directive (AD) 91-12-10, which applies only to certain King Air B200s and 300 models that were built in the mid-to-late 1980s.
The AD stipulates that somewhere between 8,300 and 9,500 hours of airframe time (depends on the King Air model), the wing bolt attach fittings must be modified using a specified kit. When the factory changed the lower forward wing bolts from “in tension” to “in shear,” they didn’t like the design of the spar attach points on certain King Air models and AD 91-12-10 was the result.
The AD lists the affected King Airs by serial number, which I have included in the box (right). There’s your answer on “who” is affected.
What Happens?
To comply with this AD, the wings must be removed … yes, removed. Of course airplanes are disassembled and reassembled every day, so what’s the big deal? If it’s your airplane, it’s a huge deal. When the wings are pulled off a King Air, all the electrical connectors for lighting, fuel quantity, etc. are disconnected; all the plumbing for the fuel system is disconnected; and all the cables for the control surfaces (ailerons, aileron trim tabs, flaps) are disconnected. It’s major surgery.
Once the kit is installed, everything is reassembled and the wings are put back on the airframe. Of course, that is easier said than done. Things always come apart faster than they go back together.
Where To Go?
If I’m asked where to take a King Air for this job, I always recommend Textron Aviation’s service center in Wichita, Kansas (KICT). If there’s a King Air out there that is affected by this AD and has not yet had the kit installed, I would take it there. This is not the time to shop around for a “good deal.” The service center there has all the necessary equipment and experience to get this Wing AD done properly.
Inexperience with the major maintenance required by this AD can have devastating consequences. This cannot be emphasized strongly enough. You do not want to go down that road, as you will soon see.
An Ordeal to Avoid
Years ago, a small charter business had a fleet with a couple of King Airs, plus some Barons and a few other aircraft. The owner-operator was methodical and attentive to the maintenance requirements of his fleet. One of his King Airs, a B200, was subject to AD 91-12-10. Compliance was due by 9,500 hours TIS (Time in Service).
Although most of the maintenance on his fleet was done in-house, he knew he had to go elsewhere for this AD. As the deadline approached, he made arrangements to take his King Air to a Beechcraft shop for a Phase Inspection and compliance with the AD.
When the work was complete, the owner picked up his King Air and flew it back to his home base. A couple things caught his attention on that return flight: He thought the ailerons felt funny – something was different – and the control wheel travel was greater in one direction than the other; he was certain it wasn’t that way before. These were unsettling observations, especially since the wings had been off, so he contacted the shop and took his King Air back for them to look things over.
The shop kept it for 3 days and reported that nothing was found. The owner-operator picked it up and took it home again. The ailerons still felt odd, and the yoke travel was still uneven from side to side. It was disturbing, but he didn’t know what else to do.
200 Hours Later
After 200 hours, the aircraft was due for another Phase Inspection and he brought it to my shop; I had never seen this King Air before. We proceeded with the inspection as usual, but right off the bat, I had bad news to report. (This wasn’t how I wanted to start with a new customer, but I had no choice.) The flap track rollers were a disaster. All of them were incorrectly installed – every single one – and there are 16 of them!
Every aft roller was installed in a forward position and every forward roller was installed in an aft position. Further, every roller was reversed or inverted or turned around in some way. You could not screw up flap track rollers any worse than this. It was a case study on every mistake possible. The only good thing was that no real damage was done to the rollers or flap tracks. We caught it in time.
Needless to say, the customer was furious. He wanted pictures. He was going to take the previous shop to task on this issue since they had the wings off and the control surfaces detached. He wondered out loud what I was thinking: How was this signed off during the Phase Inspection?
More Bad News
As my wife reached for the digital camera (no fancy phones back then), I got the ladder. We were getting a close-up shot of an outboard flap roller from the top of the wing. I started to manipulate the ailerons so she could get the shot, and I heard a strange grinding noise. We jiggled it again for a better shot at the flap roller and I heard the noise again – a raspy grating noise. Something was not right.
Everyone stopped what they were doing in the shop and gathered around. I moved the aileron again and – grate, grate, grate. It’s hard to tell exactly where this sound was coming from, so one guy got under the wing and poked his head into the wheel well. I moved the aileron some more – rasp, rasp, rasp. The next thing I heard was: “Oh shoot! This is NOT GOOD.”
An aileron cable, routed incorrectly, was sawing through the rib in the wing! Everybody in the shop was taken aback. Nobody saw that coming!
Inside the wing structure, the ribs have lightening holes for weight reduction. Holes for cable routing are smaller, often oval-shaped with a protective lining to prevent chafing. They are very different. It’s hard to confuse the two, but apparently someone found a way.
Since both wings had been off for the AD, we thought we’d check the other wing for good measure. We found the same problem on the other side! I was in shock.
I struggled with how to deliver this news to the already livid owner. As if the flap track rollers weren’t bad enough, I now must tell him the aileron cables are slicing through the ribs in both wings. We decided an email with a brief description and a photo of the cable cutting into the rib would be best. In the subject line, it said, “More Bad News; Call Dean Now.”
My phone rings. Words cannot describe the unbridled rage that overcame this owner-operator. “No wonder the ailerons felt so strange! No wonder the yoke was suddenly out of whack! How could they have done this? How could they have not found this when I brought it back squawking the ailerons?” Phone calls, photos and emails abounded, some with expletives undeleted. But as the tide of emotion receded, we turned to solutions.
Focused on the Fix
I sent the photos to the tech reps at Beech in Wichita. We discussed repair options on the phone. They devised a fix for the ribs and we executed it. Although we did not have to remove the wings again, we had to go pretty deep with this fix.
We disassembled the flaps and ailerons on both sides; inspected the aileron cables for broken strands, and fortunately they were still good, so we dodged a bullet there. We properly routed the aileron cables in each wing. When we reinstalled the flaps and ailerons, we made sure all the flap track rollers were correctly installed.
After reconnecting the aileron cables, we had to carry out a complete re-rig of the ailerons. We used travel boards to ensure the travel distance was correct on each side. We made sure the yoke was centered with each aileron in the proper neutral position – thus fixing his yoke problem.
Lessons Learned
Generally speaking, aircraft owners trust maintenance shops to keep their aircraft in airworthy condition; they are the maintenance experts. Still, you can’t totally ignore your gut feelings. In this case, the owner-operator knew something was amiss but felt trapped between a rock and a hard place. He took his King Air to a maintenance center for the wing attachment AD. He got it back with squawks that he didn’t have when he brought it in. He returned to the service center and they told him nothing was wrong.
He was stymied at that point and maybe started questioning his own observations. In hindsight, his perceptions were spot on. I’m sure he learned a good lesson on paying attention to his gut.
A note about the shop involved: This incident happened many years ago. The shop was newly minted and opened to great fanfare, only to close quietly a few years later. I would like to think this shop was an anomaly among Beechcraft service centers.
I have always been reluctant to criticize other shops because I know how brutal the business of aircraft maintenance is. The challenges are many, and the stress is off the charts. On the other hand, discussion of the pitfalls and common mistakes made in King Air maintenance is what I’m here to do. These are lessons for us all.
The Wing AD Today
I must say, I didn’t expect to be fielding calls about the Wing AD some 32 years after it came out. I assumed the King Airs to which it applied had the AD done by now. Ha! Haven’t I learned never to assume anything?
Some King Airs only fly 100 hours per year or get parked in a hangar for a spell. Maybe there are some which should have had this AD completed before now have somehow slipped through the cracks. This needs to be checked out right away.
Again, the serial numbers for B200s affected by this AD (also listed in the box on page 21) are: BB-1158, BB-1167, BB-1193 to 1203, BB-1207 to 1312, BB-1314 to 1334; BL-124 to 132; and BT-33. The serial numbers for 300s affected by this AD are: FA-2 to 190.
The AD can be found at drs.faa.gov or email me and I’ll send you the pdf file; it’s only two pages. I would love to hear back on what you find.
As always, safe & happy flying!