In order to use the MEL properly, it is important to clearly understand its purpose and the timing of its applicability. Because it is designed to provide guidance in determining whether a flight can be safely initiated with aircraft equipment that is deficient, inoperative, or missing, the MEL is only relevant while the aircraft is still on the ground awaiting departure or takeoff. It is essentially a dispatching reference tool used in support of all applicable Federal Aviation Regulations. If dispatchers are not required by the Operator’s certificate, flight crews still need to refer to the MEL before dispatching themselves and ensure that the flight is planned and conducted within the operating limits set forth in the MEL. However, once the aircraft is airborne, any mechanical failure should be addressed using the appropriate checklists and approved AFM, not the MEL. Although nothing could technically keep a pilot from referring to the MEL for background information and documentation to support his decisions, his actions must be based strictly on instructions provided by the AFM (i.e., Abnormal or Emergency sections). 

A Configuration Deviation List (CDL) is used in the same manner as a MEL but it differs in that it addresses missing external parts of the aircraft rather than failing internal systems and their constituent parts. They typically include elements, such as service doors, power receptacle doors, slat track doors, landing gear doors, APU ram air doors, flaps fairings, nose wheel spray deflectors, position light lens covers, slat segment seals, static dischargers, etc. Each CDL item has a corresponding AFM number that identifies successively the system number, sub-system number, and item number. Flight limitations derived from open CDL items typically involve some kind of weight penalty and/or fuel tax due to increased drag and a net performance decrement, although some environmental restrictions may also be of concern in a few isolated cases. For example, a missing nose wheel spray deflector (Super 80 aircraft) requires dry runways for both takeoff and landing. 

Each page of the MEL/CDL is divided into 6 columns. From left to right, these columns normally display the following information: 

• Functional description/identification of the inoperative or missing aircraft equipment item 

• Normal complement of equipment (number installed) 

• Minimum equipment required for departure (number of items) 

• Conditions required for flight/dispatch including maintenance action required (M) by mechanics or other authorized maintenance personnel and operational procedures or restrictions (O) to be observed by the flight crew 

## V-Speeds 

The following are speeds that affect the jet airplane’s takeoff performance. The jet airplane pilot must be thoroughly familiar with each of these speeds and how they are used in the planning of the takeoff. 

•  V$_{S}$—stalling speed or minimum steady flight speed at which the airplane is controllable. 

•  V$_{1}$—critical engine failure speed or takeoff decision speed. It is the speed at which the pilot is to continue the takeoff in the event of an engine failure or other serious emergency. At speeds less than V1, it is considered safer to stop the aircraft within the accelerate-stop distance. It is also the minimum speed in the takeoff, following a failure of the critical engine at V$_{EF}$, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance. 

•  V$_{EF }$—speed at which the critical engine is assumed to fail during takeoff. This speed is used during aircraft certification. 

•  V$_{R}$—rotation speed, or speed at which the rotation of the airplane is initiated to takeoff attitude. This speed cannot be less than V$_{1}$ or less than 1.05 × V MCA (minimum control speed in the air). On a single-engine takeoff, it must also allow for the acceleration to V$_{2}$ at the 35-foot height at the end of the runway. 

•  V$_{LOF}$—lift-off speed, or speed at which the airplane first becomes airborne. This is an engineering term used when the airplane is certificated and must meet certain requirements. If it is not listed in the AFM, it is within requirements and does not have to be taken into consideration by the pilot. 

•  V$_{2}$—takeoff safety speed means a referenced airspeed obtained after lift-off at which the required one-engine- inoperative climb performance can be achieved. 

## Pre-Takeoff Procedures 

Takeoff data, including V$_{1}$/V$_{R}$ and V$_{2}$ speeds, takeoff power settings, and required field length should be computed prior to each takeoff and recorded on a takeoff data card. This data is based on airplane weight, runway length available, runway gradient, field temperature, field barometric pressure, wind, icing conditions, and runway condition. Both pilots should separately compute the takeoff data and cross-check in the cockpit with the takeoff data card. 

A captain’s briefing is an essential part of crew resource management (CRM) procedures and should be accomplished just prior to takeoff. [Figure 15-20] The captain’s briefing is an opportunity to review crew coordination procedures for 

