Citation Winter 1999

• Do You Know Your Gear?
• Do You Know Your Oil Type And Oil Change Interval?
• SB 525-53-15 Clarification
• SB 560-54-03 Caution

Do You Know Your Gear?

Most Citation landing gear and associated actuators are cycle limited. Traditionally, cycles have been such a high number that many operators have never thought much about reaching these total numbers of cycles on many items. Because of that, some aircraft do not have a good record of tracking total cycles on gear components.

As aircraft get older, parts are changed more often, and it becomes increasingly troublesome to keep up with the total cycles on various individual components.

The FAA now requires repair facilities to record the total times and cycles, as appropriate, on components sent in for repair or overhaul. It is not unusual for Duncan to see landing gear components for which there are no known total times and cycles. By FAA regulation we cannot return a life limited part to service unless we know the total times or cycles as required.

It saves time and money to send total cycles on landing gear parts when you return a component for repair or overhaul. This information will expedite repairs of life limited components, and avoid the extra expense of replacement parts.

For more information about this or other accessory needs, please contact Chris Gress in Lincoln at 800.228.4277.

Do You Know Your Oil Type And Oil Change Interval?

TFE731 engines that have incorporated ceramic No. 4 & No. 5 seal runners per Service Bulletins TFE731-72-3596, TFE731-72-3597, or TFE731-725111, are now required to use Mobil 254 oil when servicing the oil system. In addition, the Mobil 254 oil must be changed at an interval not to exceed 450 +/- 50 hours.

Following incorporation of the above referenced SB, there were 16 failures of ceramic seal runners, all on engines using oils other than Mobil 254. It was determined that accumulated coke from the oil came into contact with the ceramic seal runners causing the runners to fail.

Mobil 254 oil has shown less tendancy to form coke than any of the other previously approved oils. If oil other than Mobil 254 has been, or is currently being used, the oil must be replaced with Mobil 254. Service Information Letter F731-89 gives the pertinent details of the requirements and procedures to be followed to comply with this requirement.

For more info, please contact Cecil Sloan or Jon Dodson in Lincoln at 800.228.4277 or Dan Arrick in Battle Creek at 800.525.2376.

SB 525-53-15 Clarification

SB 525-53-15 was issued to provide instructions to X-ray Stringers 9 & 10 in order to check for missing angles in the tailcone. If stringers were installed without angles, instructions are provided to install the missing angles.

No instructions were given for stringers which had angles installed, or if some were installed with angles and some were not. A memo was received from Citation which clarifies the instructions. If stringers are installed with the angles in place, no further action is necessary. If some stringers were installed without the angles in place, only those must be modified.

For info, contact Ed Johnson in LNK at 800.228.4277 or Joe Austin in BTL at 800.525.2376.

SB 560-54-03 Caution

During installation of the inlet vapor barrier channel per SB 560- 54-03, be particularly cautious in locating the channel along the proper row of rivets. If the vapor barrier channel is located incorrectly, it will be located in close proximity to an engine anti-ice bleed air exit hole. The channel is made of plastic and can be melted by bleed air during application of engine anti-ice.

The SB info is correct, but there are two adjacent rows of rivets, one of which is not readily apparent, that the channel is located along. It is imperitive that the proper row be located to ensure location of the channel.

For info, contact Ed Johnson in LNK at 800.228.4277 or Joe Austin in BTL at 800.525.2376.

( Return to top )