Citation Winter 2008
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Winds of Change
— Ed Johnson
We are approaching the time of the year when we see stormy weather and gusty winds that seem to change directions hourly. It is important to remember to secure the aircraft properly to avoid damage caused by wind catching control surfaces and cabin doors and blowing them against their stops.
Whenever your aircraft is parked, be sure the gust lock is properly set and locked. If the gust lock is not properly locked, it can disengage and allow the control surfaces to be blown around. Some Citation models automatically lock the controls, while others, such as the Sovereign, must have the controls in neutral before they will lock properly.
When opening the cabin door on Citation 500 Series aircraft, be aware of wind direction. Even though you parked the aircraft with the nose into the wind an hour ago, the wind may have changed direction and now be from the tail of the aircraft and very strong. Significant damage can occur to cabin door hinges and fuselage skin by wind catching the cabin door and blowing it into the door stop.
Proper Use of MELs
— Ed Johnson
Minimum Equipment Lists (MELs) are designed to allow operation of an aircraft with an inoperative non-essential system until repairs to that system can be made. They contain instructions which detail the actions that must be taken, if any, to ensure safe operation of the aircraft with the inoperative system. Depending on the system, a specific time period may be established within which the repairs must be accomplished or the aircraft will be grounded.
While operators are aware of these MELs, many believe that they apply only to Part 135 operations and then only to systems that were part of the aircraft’s original type design.
Occasionally we have instances where a customer is at our facility for inspection and we find a discrepancy with a non-essential system, such as a vapor cycle air-conditioner. We may be unable to get parts in time to make the scheduled delivery. The customer then asks us to disable the system and he will fix it when the part arrives, since it is the middle of winter and they won’t be using the air-conditioning system anyway. They believe that, since they are a Part 91 operation and the air-conditioning system wasn’t part of the aircraft’s original type design, they can disable the system and continue operation.
In order to operate a turbine-powered aircraft, whether Part 91 or 135, with an inoperative system that is part of the aircraft’s current type design, the operator must have an approved MEL for that aircraft. This includes any systems that may have been added by Supplemental Type Certificate (STC). The STC, as the name implies, supplements the original type certificate and the installed system then becomes a part of that aircraft’s type design and certification basis.
An operator may use a copy of a Master Minimum Equipment List (MMEL), which may be obtained from the aircraft OEM, usually with some type of fee, or free from the FAA website (www.faa.gov) as a template for producing his or her own aircraft MEL.
The MMEL contains lists of the systems that were part of the original type design, or that may have been added by STC. The operator can take that list and audit his particular aircraft, deleting references to systems that do not apply. He will then take the modified list to his local FSDO for approval. Only after the MEL has been approved by the FAA can it be used to allow operation of the aircraft with an inoperative non-essential system.
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