Citation V/Ultra/Encore (C560)
Maintenance Powerplant; Maintenance Airframe
Communication Breakdown
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft Aircraft Damaged; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Chart Or Publication; Human Factors; Manuals; Procedure
A Cessna C-560 aircraft came in for Overnight inspection.  An MEL on a right-hand window shade required sidewall and Emergency Exit to be removed for access to [the window] shade. Emergency Exit could not be removed. Exit had to be removed by two people; one on the inside pulling and one on the outside pounding. This has happened numerous times with the C-560 aircraft.  The Emergency Exit requires a shim seal to be made from sealant.  It appears that the shim seal was not fully cured before Exit door installation. [Recommend] the maintenance procedure for making the [shim] seal for the Exit needs to be checked.  Should we be checking the operation of the Emergency Exit during visits at ZZZ?  Emergency Exit unable to open.
Reporter stated he was referring to their Cessna 560 Encore aircraft that are being found with Emergency Exit doors stuck in the closed position. The Emergency Exit uses a plug type door that sits in the bottom of the door frame cutout and falls inward; when the upper latch handle is released. He suspects the faying sealant may seem 'cured' to the touch; but has not fully set-up in the middle of the sealant. If the Exit door is installed with the sealant in that condition; there is a strong suspicion the sealant bonds to the flat rubber seal on the Exit door after door installation.Reporter stated there was a huge problem several years ago with the Emergency Exit doors found 'glued' in the closed position on Cessna-560 Ultra aircraft. A check of their Ultra aircraft; identified some had the Exit doors 'glued' shut and unusable. He suspects the current and on-going similar problems with their 560-Encore aircraft may be occurring during the aircraft's 1200 Hour Inspection Checks. The Cessna 560 XL Emergency Exit is aft of the right wing; just forward of the Right Engine. That Exit door uses a bulb type seal on the door and so far they have not seen any Exit doors that have been found stuck in the closed position; at least none that he knows about currently.
While performing maintenance on a Cessna C-560 aircraft; we needed to remove the Emergency Exit door to gain access to [get] behind the sidewall interior panel. Unable remove the Emergency Exit door; even with one technician attempting to open the door from the inside; and another pushing and pounding on the outside frame. Fabricated tooling to allow removal of door. [Recommend to] investigate for possible degradation of rubber seal which may bond the door frame to the door opening structure. Investigate Vendors or Manufacturer for possible incomplete cure of fay/shim seal before the installation of the Emergency Exit door. Investigate if parting agent is proper material for this installation configuration.  Note: this is a recurring defect on this airframe. Flight delay. Stuck Emergency Exit Door.
Two aircraft maintenance technicians (AMTs) report an Emergency Exit door on a company Cessna C-560 aircraft was found stuck in the closed position during routine maintenance. Exit Door could not be removed or opened; even with one Technician pulling the door from inside and another Technician pounding on the outside frame. Both technicians note the stuck Exit door is a recurring issue on the C-560 Encore airframe.