New AD for wings.

[tropical]

And note the very informative and quick reply from Owen Bell as well.........................

[Gord Tessier]

Did you mean the one from the Flint guy?

[WebMaster]

Gord, he was being facetious. Pointing out that while the AD for Flint hasn't been released, we, this message board, have yet to have a comment from Owen, on the Aviation Enterprises AD.

[WebMaster]

We appreciate the comments made by anyone who has any involvement with Skymasters.
Thank you for sharing with us.

A couple of comments, questions.
First, The New Jersey accident, I thought, involved a Super Skyrocket, a pressurized airplane. I would have assumed that it had the strengthened wing. Do you mean that all pressurized Skymasters don't have the same strengthened wing?? In other words, they are not all created equal.
Second, the straps on top of the wing are only for those aircraft that do not have the 150 gallon capacity wing, and have Flint tanks? Do aircraft that do not have the 150 gallon wing, and don't have Flint tanks going to need this reinforcement?
I have seen on other types of aircraft, a need for a spar inspection. This frequent, and frequently expensive inspection is waived, if there is a spar replacement. Would not a spar replacement, incorporating spar used in the stronger wing, be a better solution than straps on top of the wing??

Thank you,

[Denhamblin]

Originally Posted by larry bowdish

We appreciate the comments made by anyone who has any involvement with Skymasters.
Thank you for sharing with us.

A couple of comments, questions.
First, The New Jersey accident, I thought, involved a Super Skyrocket, a pressurized airplane. I would have assumed that it had the strengthened wing. Do you mean that all pressurized Skymasters don't have the same strengthened wing?? In other words, they are not all created equal.
Second, the straps on top of the wing are only for those aircraft that do not have the 150 gallon capacity wing, and have Flint tanks? Do aircraft that do not have the 150 gallon wing, and don't have Flint tanks going to need this reinforcement?
I have seen on other types of aircraft, a need for a spar inspection. This frequent, and frequently expensive inspection is waived, if there is a spar replacement. Would not a spar replacement, incorporating spar used in the stronger wing, be a better solution than straps on top of the wing??

Thank you,

Larry, the aircraft involved in the NJ incident was a T337G manufactured in 1973. The 150 gallon tanks were offered later though I am unsure as to when. It may have been an option in 1974 and may have been a standard in 1975. I have one customer who operates a fleet of 24 Skymasters and they only fly those with the long wing. From my records they fly both the G and H models. The "long wing' aircraft have "hat" stringers that extend out to WS177. On the "short wing" aircraft these "hat" stingers extend to WS150. Outboard of the "hat" stringers is a spice to a "J" stringer. Additionally, the spar caps on the "long wing" aircraft have a "T" configuration of the spar cap which extends to WS177 and from that point outboard they become an "L" shaped cap. On "short wing" aircraft this transition happens at WS150.

The upcoming AD for aircraft modified with Flint Aero extended wing tip fuel tanks will only be for "short wing" 337s modified with Flint Aero extended wing tip fuel tanks as far as we can tell right now. Until the FAA signs off on our findings we can only speculate but I can say that I am very comfortable with the work of my engineer and the feedback I have received from the FAA on our preliminary findings.If you don't have the Flint Aero tips you would not be effected by this AD. If you have wing tip extensions manufactured by Aviation Enterprises you would be required to follow the instructions in that AD. However, the accident in Avon Park may bring into question the non-modified 337 wing. Since the accident in New Jersey the focus has been only on 337s with extended wing tips.

A replacement of the spar will not be required in addressing the issues incorporated in the forthcoming AD for 337s modified with Flint Aero tip tanks. There may be other ways to address the issue but we think our solution is one that addresses the issue in the most economically feasible way. According to my engineer, and he has been in this trade for many years, this has been done before on other aircraft.

[Alfonso]

Copy of email message sent today :

----- Original Message -----
From: Alfonso Diaz del Castillo
To: Dennis Hamblin ; jose.obregon@ntsb.gov ; william.o.herderich@faa.gov
Cc: Alfonso Diaz del Castillo
Sent: Friday, December 03, 2010 9:51 AM
Subject: SECOND C337 DOWN DUE TO WING FAILURE

Hello Dennis and (Jose and William), it has been sometime since our last communication. I hope you all are doing well.

Dennis, thank you for posting in the Cessna Pilot Association’s (CPA) web board, your article of the additional and pending Airworthiness Directive (AD) for the Cessna Skymasters. Please email me the complete list of all the Skymaster forums that are out there, as it will be very helpful. I am a member of CPA, but it is not a Skymaster forum per se.

In your article posted in CPA you mention that the recent C337 incident in Avon Park, Florida, does not have wing tip extensions. Have you check with the NTSB or the FAA to verify that it positively did not have now or before Aviation Enterprises winglets? I believe the winglets could provide for bending, pulling and pushing effects on the wing, and could have had some effect in both incidents, in addition to the fuel wing tip extensions.

Thank you for your input and best regards,

Alfonso Diaz del Castillo - (C336 - N695AD)

Phones: Cell 202-309-3969 - Office 571-227-2208 - Home 301-934-9100 - Fax 301-934-2111

----- Original Message -----
From: Alfonso Diaz del Castillo
To: jose.obregon@ntsb.gov ; william.o.herderich@faa.gov
Cc: Fiestair@erols.com
Sent: Friday, March 26, 2010 8:09 AM
Subject: THREE PICTURES OF A SKYMASTER WINGLET


Good morning William and Jose.

Enclosed are three pictures of a winglet on a Skymaster C337 that I took on Oshkosh last year (I believe it is an Aviation Enterprises winglet). It may be helpful to you in visualizing how big it really is and how it may have affected the flexing of the wing on the accident C337 aircraft under your investigation, especially if it is not perfectly aligned with the centerline of the aircraft. I hope these pictures are helpful to you.

Best regards,

Alfonso Diaz del Castillo - N695AD

Phones: Cell 202-309-3969 - Office 571-227-2208 - Home 301-934-9100 Fax 301-934-2111

[Gord Tessier]

It's all that cold weather up here. I thought he might be kidding. Thank you Larry for letting me be a part of this forum and this website. It is such a good feeling to know that I am not alone. I use my plane only for personal use and humanitarian missions. In January we were part of the Haiti airlift with Bahamas Habitat and when the weather permits we do Hope Air missions flying kids who need non urgent medical treatment from the near north down to Toronto.
The Skymaster is a great aircraft and I hope to be able to fly mine for a long time.
It's unfortunate for everyone involved that this happened.
All I am looking for is the cost to repair my plane not one red cent more.
Thanks again

[Gord Tessier]

Well, here we go. It appears Aviation Enterprises, though guilty of creating an unsafe condition and I quote from the AD 2010-21-18

"Unsafe Condition
This AD was prompted by a wing overload failure and by reports of cracks in the upper wing
skins on certain Cessna airplanes that are now or have ever been modified by Aviation Enterprises STC SA02055AT, SA02056AT, SA02307AT, or SA02308AT. We are issuing this AD to detect and correct damage in the wings and to prevent overload failure of the wing due to the installation of the STCs. Damage in the wing or overload failure of the wing could result in structural failure of the wing, which could result in a loss of control.

At first they were willing to accept responsibility. Then they asked for proof that the work was done. Then they wanted all the engineering data (I speculate so they could copy it and use it to create a fix for the remaining aircraft) and finally they finished off by asking me for the "weight and balance for every flight since the STC was done". Of course that information does not exist.

Instead of doing the right thing they have decided to hide and hope that myself and the other aircraft owners will just go away. Well, I can't speak for the others but I can tell you right now that I will not go away until I am reimbursed for the damage caused. I have availed myself to one of the legal firms that my company uses in Tennessee and I will be litigating. They did over $21,000 damage to my aircraft.

When I am finished I am told the cost to them including legal fees and damages will approach or exceed $100,000. The firm I am using has extensive experience in this area.

[Denhamblin]

I just spoke with my engineer and he did say he was wrong in his assessment of the zero fuel weight (the gross weight of the aircraft) for the "short wing" 337s. It appears that will be 3,400lbs. You do need to keep at least 12 gallons of fuel in each tip tank until your weight drops to this point. Once the aircraft is reinforced this will go back up to 4,330lbs. I am still waiting on hearing how much fuel you need to keep in each tip at higher gross weights. Right now I would say keep your tips full until you get your weight down to 4,330lbs and then transfer some fuel out of the tips but you need to keep at least 12 gallons in each tip at 4,330lbs.

Again, this will only effect the "short wing aircraft." If you have the factory 150 gal tanks you are fine with the STC as it is currently written.

Also, I think it is important to add that our engineering numbers only deal with a total gross weight of 4,700lbs and below. Technically, our STC only provides a GWI up to 4,630lbs (that of a non-turbo 337G).

[WebMaster]

It's unfortunate, Gord. I would think that they (Aviation Enterprises ) would want to get things straight. Resorting to attorneys makes attorneys happy. Unfortunately, I think that Aviation Enterprises would end up being not happy. I know of a similar case, and the plaintiff ended up owning the company, or at least it's assets.