* Fuel Pump Fu
This is the new sliding vane pump that PZL has produced to replace the 4886 diaphragm pump which is the subject of the Emergency Airworthiness Directive of August 2000. As you can see, the new drive unit bolts onto the rear of the engine, replacing the old drive unit with its cam and lifter assembly and pump receiver housing entirely. Click here to see the PZL Service Bulletin that started it all.
* Nosewheel Shimmy
Many Rallye pilots have experienced shimmys on landing. These can be quite violent. The noseleg and nosegear and nosewheel axle are the subjects of several Airworthiness Directives. The Rallye List has an extensive thread on shimmy dampers, internal pump jets, tire pressure and ground handling technique. Do not take landing shimmy lightly. As time permits, all applicable ADs will be posted in the Rallye Repairs section of this website.
Click here for some details on shimmy.
* Oleos *
SOCATA oleos are all that are now available. They can be rebuilt with parts kits from Socata. Upon completion of rebuild, introduce 153 cc of fluid thru the Shrader valve at the top of the shock and then replace the valve core. Then add nitrogen - 479 psi or 33 BAR to mains and 522 psi or 36 BAR to the nose unit. (With technical thanks to George Johnston and Lloyd Davies.)
* Slat dampers
The heavier airframe Rallyes have air dampers (called “dashpots” in the manual) that are designed to prevent slats from deploying or retracting too forcefully. These units are located inside the wing and are accessible with flaps extended. Accessible is a very relative term. The dampers have a rod with two pistons inside the damper housing. The rods are attached to the bell crank assembly that ties the slats on each wing together. When the slats move quickly, the pistons damp the action by forcing air through two tiny holes. For proper operation, the seals around the pistons must be tight agains the tube walls. The manual calls for lubricating the pistons with several drops of lubricant to keep the seals pliable. This in turn requires a method for introducing the lubricant while actuating the slats. Best done by removing units and immersing in lubricant and working the pushrods. The idea is to suck some lubricant into the tubes through the tiny air holes. Second best way is with two or even three people and a lubricant with a long, flexible tube that can squirt lube into ends of tubes as someone manually works the slats and hope the lubricant makes its way on to the seals.
Recently we had a problem with oil seepage just ahead of the carb on our 0-300 Continental. Removal of the oil sump showed pitting and corrosion around the front drain plug area. The casting was being eaten away by corrosion.
The air induction port which is cast into the sump has a 3/8 inch
hole on each side of it for oil to drain back into the main part of
the sump. Moisture tends to gather in the front portion of the sump.
We found there was a couple ways to go to repair this problem. We
could have the sump bead blasted with plastic media and repaired with epoxy. Or, we could purchase a serviceable sump. The price for a used sump was anywhere from $700 usd to $1750 usd. A new sump was quoted at $3000 usd. Probably a good preventative maintenance tactic would be to remove the front drain plug and use a scope to have a look during the annual. We've since heard that this is also a problem on the older Cessna 170 and 172's.
Rudder Pedal Rods - from George Johnston To download the Service Bulletin, click here.
Back in the 70's Socata realised that there was the potential for those rods to bend and break. They repaired this by redesigning the connection between the pedal and the rod. This was published as SOCATA service order # 120, CR 27-13 ( I do not know what that means),modification #123. This modification required replacing the existing eye bolt and standard hex nut with an undercut eyebolt and a guide nut ( quite different from a standard hex nut). Now SOCATA identify Rallyes in two catogaries, light airframes and heavy airframes. Light airframes are: MS.880.B, MS.881, MS.883, MS.885, MS.886, MS887, 100.S, 100.ST, 150.T, 150.ST.
Heavy airframes are: MS.890, MS.892.A.150, MS.892.E.150, MS.893.A, MS893.E, MS.894.A, MS894.C, MS.894.E. Now, light airframes with serial number 2622 and above and heavy airframes with serial number 12622 and above were produced at the factory with the modified eye bolts and should be OK. Light airframes with serial number 2621 and lower and heavy airframes with serial number 12621 nd lower should have been modified back in the 70's and a notification put in the log book. These airplanes should be checked and modified now if required. It's easy to tell, just push the outside pedal all the way forward and feel the eye bolt and the rod, there should not be a standard hex nut. If there is a hex nut then the parts you require are, and here again you must refer to the serial
number as there are different threads on the rudder rods. Light airframes up to ser.# 2453 and heavy airframes up to ser.#12453 had rods threaded with "SI" pitch in which case you must use the undercut eye bolt #818.104.22.1684.0 and the guide nut #880.16.0.059.0. Light airframes from ser.#2454 and heavy airframes from ser.# 12454 have "ISO" threads and require undercut eye bolt #822.214.171.1242.0 and guide nut 8126.96.36.199.0 Note these may well be out of date part numbers but SOCATA should be able to find the right ones. Question, has any one with a Rallye with a ser.# 2622 and 12622 or above experienced rudder rod breakage ? Please let me know. George.