Piper PA-28 control column tee bar assembly cracking and failure - Civil Aviation Safety Alerts (CASA) No. 2016-14
Owners, operators and maintainers of Piper PA-28 series aeroplanes
|Issuing Office:||National Aircraft Certification|
|File Classification No.:||Z 5000-35|
|Document No.:||CASA 2016-14|
The purpose of this Civil Aviation Safety Alert (CASA) is to raise awareness of the possibility of cracking and potential failures of control columns installed in Piper PA-28 series of aeroplane.
A Piper aeroplane, model PA-28-140, was on a local training flight with an instructor and student on board. On approach to the runway, a forward slip was conducted. While the aeroplane was rounding out at approximately 5-10 feet above ground level, the aeroplane’s control column failed resulting in sluggish and delayed flight control response. The aeroplane rounded out enough to settle onto the runway and landed safely.
A subsequent inspection of the flight control system revealed a complete failure of the tee bar assembly/ control column (Piper part number 62703-033). The horizontal tubular steel structure had completely fractured at the “T” section weld where it intersects with the vertical steel tubular structure.
A used replacement control column assembly was removed from an out-of-service aeroplane. This column had only been previously used in the out‑of‑service aeroplane from which it was removed. Prior to the replacement column being installed on the incident aeroplane, the replacement control column was examined using Magnetic Particle Inspection (MPI). The MPI revealed cracking around the T section weld at the intersection of the horizontal and vertical tubular steel structures.
Both aeroplanes had spent their entire time in service in a flight training environment and had accumulated over 18 000 hours of time in service. Flight training environments can be inherently more demanding on aeroplanes due to sudden, harsh and repetitive flight control inputs. Prolonged operation of aeroplanes in such environments can result in fatigue of aeroplane components, including the control column.
A review of the Piper Illustrated Parts Catalogue (IPC) revealed that the design of the control column installed in the incident aeroplane is very similar to the control columns installed on other PA -28 models, including PA-28-150, -160, -180 and -235 models. Consequently, the type of failure seen on the incident aeroplane is not limited to the specific part number of the control column installed in the incident aeroplane. This type of failure could potentially manifest itself on other part number control columns installed on other PA-28 series aeroplanes with similar Tee bar control column assemblies.
The PA-28 series aeroplane inspection program requires that the control column be visually inspected at each annual or 100 hour inspection. The control column is located behind the instrument panel and is difficult to access for inspection. Cracks that were found on the replacement control column were undetectable to the naked eye, even after it was removed from the aeroplane. It is likely that high time PA-28 series aeroplanes may be at risk for undetected control column cracking and or potential failures.
The United States of America is the state of design for Piper Aircraft. Piper Aircraft is continuing to investigate the failures of the two control columns but have not yet made a final determination of what action, if any, will be taken as a result of the findings. Transport Canada will re-assess the situation as more information is obtained.
Transport Canada recommends that owners, operators and maintainers of Piper PA-28 series aeroplanes perform a Detailed Visual Inspection (DVI) of the control column assemblies installed in their aeroplane as soon as practical with particular emphasis on inspecting the T section welds at the intersection of the vertical and horizontal tubular structures for any cracks.
Transport Canada also recommends that owners, operators and maintainers of Piper PA-28 series aeroplanes remove the control columns from their aeroplane at the next scheduled annual or 100 hour inspection and perform a Magnetic Particle Inspection of the control column T section welds to determine if cracks are present.
If any control columns are found to be cracked or defective, remove the columns from service before further flight and submit a service difficulty report (SDR). An SDR may be submitted in paper format or on-line via the Web Service Difficulty Reporting System (WSDRS).
For more information concerning this issue, contact a Transport Canada Centre; or contact K. Bruce Donnelly, Continuing Airworthiness in Ottawa, by telephone at 1-888-663-3639 or by fax at 613-996-9178, or by e-mail at CAWWEBFeedback@tc.gc.ca.
ORIGINAL SIGNED BY
The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.