Update #3 Rudder Post AD


The Short Wing Piper Club is providing this update on the status of the effort to modify or withdraw the NPRM  (Notice of Proposed Rule Making) requiring replacement of the rudder on most fabric covered vintage Piper aircraft.  The NPRM can be seen by clicking here and then on the NPRM title. The supporting data provided by the FAA and the NTSB is available by clicking here on supporting data. Many of you have made comments and request an extension of the comment period which was successful. And the comment period was extended to February 20, 2024.  You can see the comments by clicking here.  We thank you for your support but we still need your help.  First let us briefly let you know what we have found and what our plans are.  We have:

1.Determined that this NPRM is in fact based on only two incidents where there is any data defining aircraft configuration and operation mode. This data is required to determine the root cause of the failures. All of the other failures cited in the NPRM are anecdotal with no data available on N-number, aircraft configuration or operating mode.

2. Determined both Aircraft, for which data is available, were not in an airworthy configuration in that both aircraft were required to have ventral fins installed.  This requirement is established either by Type Certificate or by the STC used to install the floats. Neither aircraft had a ventral fin or acceptable alternative.  This directly impacts the load on the rudder and in combination with other modifications, such as the rudder beacon and larger engines and props , could have caused the failures in the rudder post.  The FAA should have done enough investigation to determine these facts before issuing such a broad NPRM.

3. Shown, based on FAA data, the 1025 steel used to fabricate the original rudder posts  meets the design stress limits for the aircraft as produced.  The proposed 4130 steel rudders would only increase the margin. This is based on the stress analysis performed by the NTSB on the two accident aircraft.

4. There are many other errors in the NPRM that demonstrate a lack of adherence to the regulations and manuals that regulate these procedures.  This is one area where we will need additional help from all interested parties.  We need additional comments to the NPRM (it is permissible to make multiple comments) similar to the letter you can see by clicking Letter here specifically requesting the FAA complete the NPRM and provide the required data.

5. We have also embarked on a testing program in an effort to determine the root cause of these failures, what aircraft any regulatory action should apply to, and possible appropriate corrective actions to prevent further failures.  This  work is time consuming and expensive, and should have been performed by the FAA prior to issuing an NPRM of this size and magnitude.  We will be sending out a survey within the next couple of days to collect information on aircraft and any problems owners may have encountered with this issue.  Important information includes the aircraft configuration and modifications that could impact the rudder.  Keep an eye on your mail inbox (or spam folder) and please fill out the survey and return it.  It will be very easy to do.

We want to thank all who have sent comments to the FAA on this issue as well as thank the many organizations and people who have volunteered their time and resources to this effort.  There are too many to identify them all here, but will do so at an appropriate time and place.  In the meantime, if you appreciate the effort the Short Wing Piper Club is putting forward to protect its members please encourage others that may not be members to join the club and support a fantastic organization

Clear Skies

Your Short Wing Piper Club