Over the years, there have been a significant number of SOAR and defect reports involving incorrect rigging or connection of Jantar aileron and elevator controls, and this seems to be a perennial problem
David Villiers
Chair Airworthiness Panel
Over the years, there have been a significant number of SOAR and defect reports involving incorrect rigging or connection of Jantar aileron and elevator controls, and this seems to be a perennial problem. Recently, there has been another instance of a Jantar being incorrectly rigged. In this instance, as in several previous cases over the years, the ailerons were found to be improperly connected. The problem was discovered after a flight when the pilot lost roll control after touchdown. Upon inspection, it was found that the left aileron pushrod was completely disconnected from the aileron lever in the fuselage, despite the release button on the connector being in the locked position. Inspection of the right aileron connections showed that the connection to the right aileron pushrod was incorrect as well. The release button was close to the correct position but was not properly locked, and the yoke of the connector was only engaged on one side of the wing pushrod fitting. An article on Jantar pushrod connections was published in Gliding Australia Number 51 in early 2020 (pp. 38 & 39).
The flight on which the recent defect was found was the fourth flight after an annual inspection. An independent inspection, followed by a positive control check, was performed before a successful evaluation flight. The aircraft flew twice more before the problem was discovered upon landing after the next flight.
This aircraft had not been derigged/rerigged since the annual inspection. This means that the aircraft was subject to more than one DI after the evaluation flight, where the incorrectly connected ailerons were not discovered.
The Jantar control locking mechanism is used on both the aileron and elevator connections, but it is not a foolproof system. It needs careful examination by someone familiar with the system to ensure that the connections are properly made. To complicate matters, the connections are in positions that are difficult to see directly, and this may be exacerbated by the orientation of the connector. The aileron connections are accessed through an inspection panel in the turtleback of the aircraft, and the elevator connector is under the horizontal stabiliser. Neither can easily be seen. The release button may be on the far side of the connector and not visible through the inspection hatch or hole.
The connector, which is unique to PZL aircraft, is intended to have both locking washers inside the yoke when properly connected, but it is possible to make the connection with one locking washer outside the yoke or, as in this case, to engage one side of the pushrod fitting only.
In these cases, the fact that the release button is in the correct position does not prove that the connection has been correctly made. Only a careful visual inspection can confirm the correct connection. Feeling the indicator pin in the correct position is also not proof that the connection has been achieved correctly. Proper inspection of this connection is best ensured by a visual inspection, and the aileron system in particular may require use of an inspection mirror and a torch.
In this case, it would appear that the people doing the rigging, the daily inspection and the independent check after the annual inspection all overlooked the misrigging of both ailerons, and that only luck prevented a far more serious outcome. More disturbing is the fact that subsequent daily inspections also failed to catch the faulty connections.
All pilots who conduct a DI on a Jantar need to have a clear understanding of its control connection system, and that applies also to pilots who are asked to do the independent inspection. A pilot who is not familiar with the Jantar system is not the best person to do the independent inspection.
If the inspector carrying out the aircraft rigging and control connections, or inspector performing the duplicate inspection, is not familiar with the aircraft type and/or control connections, extra due diligence is required. Either assistance should be sought from someone familiar with the system, or the aircraft’s flight and/or maintenance manual must be consulted to confirm correct control connection and assembly. A torch and mirror are essential to confirm correct assembly.
Independent Inspections
MOSP3 requires that after a control system is reconnected for any reason, an independent check for 'correct assembly and safetying' is to be carried out by someone holding a DI authorisation or higher (MOSP3 10.7.2 d. and 11.2 refer). Such a check should be:
l Made by a person with knowledge of the system to be inspected.
l Independent of the person making the connection and conducting the initial inspection. An inspector who is shown what to do by the person who made the connection is not 'independent'.
l Documented in the Maintenance Release of the aircraft inspected.
Just because a pilot holds a DI authorisation does not make them an appropriate independent inspector. A person asked to do an independent inspection who is not familiar with the aircraft or system to be inspected should politely decline – remember, if there is an incident or accident, someone will be asking the independent inspector to explain what they did and how.
Daily Inspections
The purpose of a Daily Inspection is to establish that the sailplane is fit for flight for that day’s flying operations (DI Handbook reference). This means that all critical systems of the aircraft, including its rigging and control connections, should be checked. Step 2 of the Daily Inspection Schedule contained in the Maintenance Release makes that plain. All these connections should be carefully checked at each and every Daily Inspection. In some types – and the Jantar is one – this means the opening of an inspection panel and may require tools such as an inspection mirror and a torch. Other types may need a screwdriver or other implement to open a panel. Tape and a knife or scissors may also be needed to reseal the panel after inspection - and, of course, all tools used to do a DI must be accounted for afterwards!
There is never a reason to shortcut a DI, even if you are the only person to fly the aircraft. Mechanical systems are subject to failure and human error. Unintended passengers (think mice, snakes and spiders) are also a hazard that can be addressed through a careful DI. Failure to check something important because “I checked that when I taped the panel closed after the last time I rigged it” is never a good idea – your life, and that of others who may fly the aircraft, are worth much more than the extra five minutes needed to do the DI properly.
