Date: 201405
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Dusk
Aircraft: Citation Excel (C560XL)
Operator: Fractional
Operating under: Part 91
Flight phase: Taxi
Aircraft component: Minimum Equipment List (MEL)
Reporter organization: Fractional
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Maintenance Action
Contributing factors: Aircraft; MEL; Human Factors; Company Policy; Chart Or Publication
Primary problem: Company Policy

Narrative: May 2014.  The flight crew assigned to a Cessna 560XLS was sent the following information regarding a question that arrived from the application of what our Operator Maintenance Control coined an 'Emergency Non-Essential Function (NEF)' that was applied to the aircraft eight days prior.  The deferral was for two adjacent rivets; which seem to be of structural nature; on the Air Cycle Machine (ACM) containment box. 'Environmental Control Unit (ACM) in Aft Accessory area is missing 3rd rivet from left and 2nd rivet from left appears to be coming out after flight.  Some of the data for all of our past deferrals is located in our computer drive which is currently unavailable.  If a discrepancy does not fall within the list in the NEF section; we can accomplish an 'Emergency NEF' which requires numerous approvals on the Maintenance and Operations sides.  When approved; the item will have an NEF deferral; however; because it does not fall within the published list [of NEF items] it will not have the added digit numbers.  These items go into a history database located in the computer drive which we may refer back to when a similar item presents itself.  If an item has been approved in the past; we [pilots] may elect to approve [the NEF deferral] in the future based on precedence and without the need to run the approval process again.  I believe the Fleet Manager is working on a permanent approval for a limited amount of rivets sheared or missing from the ACM mounting hardware.  If the need arises; I will approve of the one missing and one loose rivet provided the others are visually secure.  As an FYI; all of these One-Time approvals are forwarded to our local FSDO for their review.   Maintenance Technical Representative X in our Maintenance Control noted that the Aircraft was operated on a Special Ferry Permit authorization.  The following information and the Assistant Chief Pilot (ACP) On-Duty ensured us that it was legal and compliant to operate the aircraft.  I have a few questions regarding such so-called 'Emergency NEF's':  1) I was not able to find any reference to approved Emergency NEF procedures within the NEF Manual or the FOM. Where can one read about said approval?  Where can one find the List of previously approved 'Emergency NEF' deferrals?  2) With company Operations at Level IV Safety Management Systems (SMS) approval by the FAA in mind:     A) Where are the checks and balances to ensure acceptable risk assessments are maintained for such 'Emergency NEF' deferrals?  It seems that our Maintenance Technical Representative has the authority to utilize such deferrals without FAA and Original Equipment Manufacturer (OEM) approvals and oversight.     B) In case our company can utilize such emergency NEF deferrals to seemingly any Maintenance discrepancy; why even have a published 'accepted' NEF List; or; Special Ferry Flight permits for that matter?      C) How can a Crew member confirm the safe; legal; and compliant application of such 'Emergency NEF' authorization beyond our company's claim?     D) Why allow such 'Emergency NEF' deferrals to be in place for 10-days?  One would think that by the use of the word 'Emergency'; such deferral would be needed for a short period of time to get the aircraft to a Maintenance Base.     E) There seems to be an inconsistent application of said 'Emergency NEF'; some Maintenance Control personal will AOG the aircraft for the same discrepancy and some will seemingly apply this 'Emergency NEF'.  Why the inconsistent application of Maintenance procedures within the same SMS Level IV approved Operator?  3) These rivets seem to be structural in nature and Cessna's history does not lead one to believe more structural reinforcement is applied then needed by certification: How can a process intended for 'Non-essential equipment and furnishings' be used for what seems to be a structural issue?  Airline Transport Pilot.

Callback: Reporter stated they now have the Minimum Equipment List (MEL); the Configuration Deviation List (CDL); the Non-Essential Function List (NEF) and now the Maintenance Carry-Over List (MCO) where discrepancies can be deferred or moved to. His company wants their pilots to defer items based on prior approval by their Maintenance and Operations group. But; he feels the information provided is not adequate enough for Flight Crews to be deferring items or determining the aircraft's Airworthiness based on the limited information given. He has not received any response to his concerns as of yet.



Synopsis: A pilot questions the application of a 10-day 'Emergency' Non-Essential Function (NEF) deferral for structural missing/loose rivets in the Aft Accessory Bay of a Cessna 560XLS for the Air Cycle Machine (ACM) mounting hardware. Pilot also addresses the inconsistent application of an 'Emergency' NEF when other Maintenance Control personnel will ground the aircraft (AOG) for the same condition.