A look at B-17 Yankee Lady's wing inspection after grounding
ฝัง
- เผยแพร่เมื่อ 1 ก.ค. 2023
- Anyone who is a fan of warbirds or has been following aviation news probably at this point has heard about EAA’s B17 “Aluminum Overcast”. While on the road in spring of 2021, the aircraft was grounded following evidence of movement on a wing fairing. While investigating the issue, a crack was found in the left wing’s sheer web. Because of this event, the remaining 8 B17 operators grounded their aircraft in preparation for the AD inspection that would be issued by the FAA.
Because of the unknown of what the inspection would entail or if the aircraft would be allowed to ferry back home if it was on the road when the inspection came, Yankee Air Museum opted to ground its B-17 for the 2023 season so it would not get stuck anywhere. In May 2023, the FAA released the AD outlining the inspection procedures. I recently had the opportunity to work with the Yankee Air Museum as the inspection procedure became live. In today’s video we take an up close look at the inspection procedure that took place on Yankee’s B17 named “Yankee Lady”
To take a look at the procedure, we dive into the wing root of the B-17, where the wing is connected to the fuselage. Although each wing has a forward and aft web spar, each having 2 primary mounts on it, the inspection is only concerned with the lower forward mounting areas on each wing. The affected area for the inspection is the inboard most bolt hole on the wing terminal which is where Aluminum Overcast was discovered to have had a crack. The terminal, in simple design terms, is more or less a fork with 2 tabs which 3 pins run through connecting the wing to the fuselage. The terminal is made of steel and slides into an outer aluminum piece which then mounts to the aluminum sheer web wing structure. Although it is held by multiple bolts, only the inboard most bolt hole is concerned because if a crack forms there, the end of the terminal could completely shear off, separating the wing from the fuselage. In theory, if there was an issue with any of the other holes, the terminal would still have bolts downstream of the defect hole holding it in place.
In order to perform the inspection, the bolt filling the hole in question must be removed. To gain access to remove the bolt, a section of the wings rib structure is cut out. This will later be replaced with a splice which can be easily removed and re installed in anticipation that this becomes a repetitive inspection. Once the bolt is removed a type of non destructive testing called eddy current is used to inspect the hole for cracks. A special spinning bolt hole probe is used in this procedure. This method of testing uses an electromagnetic field created by the coil that is induced into the material it is being tested. Any defects, whether on the surface or subsurface will change the impedance showing a change in phase and amplitude on the machines readout. This inspection procedure is widely used in the aerospace industry and notably used to inspect the fan blade roots on the CFM56 engine following an uncontained engine failure due to a crack on a Southwest Airlines Boeing 737 in 2018.
Thankfully for warbird and B17 lovers, both of Yankee Lady’s wing terminals and surrounding structure were found defect free, giving the aircraft a clean bill of health after the inspection. With a little bit of reassembly and all the paperwork, the aircraft will be back in the air soon.
The Yankee Air Museum is located in Michigan at Willow Run airport with various building locations on the airfield. Notably the museum takes up a portion of the historic Willow Run bomber plant which used to produce the B-24 in World War II as well as the building and hangar that used to house the Michigan Institute of Aviation and Technology before it relocated to a larger building. In addition to the B17 “Yankee Lady”, the museums flying fleet which is housed in the Roush Aeronautics hangar consists of a North American B25 named “Rosie’s Reply”, a Douglas C47 named “Hairless Joe”, a 4-AT-B Ford Tri-Motor and a UH-1 Huey helicopter as well as many non flying static displays.
Lately I have been posting different types of content as the channel grows. This type of video is a little different than the normal commercial aviation my channel is focused on so let me know what you think and leave a comment below if you liked it. As always, don’t forget to like and subscribe if you haven’t already. Thanks for watching. - วิทยาศาสตร์และเทคโนโลยี
LOVE the old war birds!!!
As this issue was discovered on Aluminum Overcast it makes one wonder if it might have has something to do with that landing gear failure back in 2004. It will be interesting to see if any of the other B-17s have developed the same crack.
This issue isn’t a surprise to the operators. It was already on folks radar, and the FAA had addressed it some years ago as a potential future problem. As I understand it, the discovery on AA spurred the FAA to come out with an updated directive now that the problem has advanced to a genuine safety concern, and is no longer a “this could be a problem in the future” type concern. It’s an inherent issue in the design that everyone knew about, and in theory will eventually affect all the airframes, it’s just a matter of time.
@SkyWriter25 It would be hard to say what all had a factor into this. Its a 70+ year old plane, I dont think anyone really knows what all its been through in its life or what type of stresses were put on the airframe during that time.
Great to see an old plane taken care of and back in the air
Several years ago I came out of a business and heard a strange rumbling. I looked up and what did I see a beautiful B17 flying low and slow overhead. I had only one word top into my head. That word was , WOW !🙂
I am very thankful to have been able to ride in this plan, it is a unforgettable experience and if you get the chance do it.
Great
nice explanation of a typically complicated AD instruction
Thanks. I didnt see much detail or photo documentation on the internet about Aluminum Overcast. Just that it had and issue. So I thought it would be kind of cool to give people a look into what the issue was and what was being done about it.
Grounded for about a month, coinciding specifically with the only airshow I get to attend and that Yankee Lady had to miss. Oh well, hope to see her next year!
It’s one thing to draw a design for a new bomber on a napkin in a restaurant. But all the parts that go into it. Holy cow. Who knew! Nice video would like to see more. My father was aircraft maintenance for his career in the Air Force. Talk about books full of how to’s
Thanks
I've flown on her, I live close to willow run so when she flew again I knew. It shakes the neighborhood as she's on final approach
I live near Willow as well. I can always tell when they are out flying
(late to the party)....
Not to brag or anything(!!!)...but I got free rides on "Lady" and "Warrior". I happened to be working out at Howell airport when they came in.
I did my instrument rating at Willow (back in 07). I got many taxi clearances..."Follow the 17" (or 25 or 47). I learned real quick, to keep a good distance behind em!!!
I did recently hear (last month) that "Lady" was/is trapped inside their new hanger. The door failed, and the company that made the door is being zero help and not backing their product.
I am used to seeing her out and about on a weekly basis (Hamburg/Whitmore Lake area)...and her absence is definitely noticed.
This was interesting. I never knew so little connected the wing to the aircraft hull.
That's the case for most aircraft actually
Awesome video showing exactly what is being done. Thanks!
Thanks
These aircraft are living memorials to a nation that stood up to tyranny. They deserve all the care and attention possible in order to keep our memories of those sacrifices alive.
Im so glad she passed inspections and is back in the air where she belongs.
Yup, they do a good job keeping up on the old birds
Great video and content. More anytime. Thanks.
Thanks
That was a great explanation of the issue. Thank you!
Thanks
Excellent thanks
Thanks
Great Video, Wonderful explanation!
Thank you
Very good and informative video.
Thanks
As an information junkie this video satisfies the information itch with a good scratch. Well done and I hope to see more.
Thanks
The Yankee Lady holds a dear place in my heart, not because I've flown in her, but because I used to live in Michigan and I've seen her in the air on many occasions. Some time , I would hope to fly on her, more so than on any other B-17.
Cool
Sorry but i don't speak English what the hole in the wings at 1:08 please ?