3.
As Aircraft Gross Weight decreases, adjust IAS downward.
The flight crew should compare the predicted performance figures in Section 5 (IAS, EPR, N1/N2 and fuel flow) against actual figures as a check of true outside air temperature and airplane/engine conditions.
Trim Techniques
Note: Check fuel and engine thrust are balanced before trimming.
Autopilot Disengaged
.
Set aileron and rudder trim to zero.
.
Hold wings level using horizon and ADI as reference. Do not trim ailerons at this time.
.
Use rudder trim to stop any turning tendency. When no turn exists, the rudder is properly trimmed.
.
Use the aileron trim to remove the control wheel force required to hold the wings level.
.
The aircraft is now trimmed for the configuration and speed.
Autopilot Engaged
.
Set aileron and rudder trim to zero.
.
Select heading hold and altitude hold.
.
Use rudder trim to remove any control wheel deflection. Do not use any aileron trim.
Stabilizer Trim
. Periodically disconnect autopilot and adjust stabilizer trim if aircraft climbs or descends
Cruise Performance Economy
The dispatch computed fuel burn from departure to destination is based on certain assumed conditions, (i.e., takeoff gross weight, cruise altitude, route of flight, temperature, wind enroute, and cruise speed). The planned fuel burn can increase due to:
.
A lower cruise altitude than planned.
.
More than 2,000 feet above optimum altitude.
.
Speed faster than planned or appreciably slower than long-range cruise if planned for long-range cruise.
.
Stronger headwind component.
.
Unbalanced fuel.
.
Improperly trimmed airplane.
.
Excessive thrust lever adjustments.
Engine Synchronization
Switch the system on (N1 or N2 position) only after cruise thrust has been set and the N1 RPM have been manually adjusted to within 1% of each other.
After a reasonable length of time, determine if synchronization system is functioning properly. If not, select sync switch to OFF and disconnect autothrottles for at least 5 seconds. Reconnect throttles, adjust N1 RPM again using a slightly different “match-up” than the first time. Select sync switch to ON (N1 or N2) position. Again, after allowing a reasonable length of time, determine if system is functioning properly. Several N1 RPM adjustments may be necessary.
Prior to initiating a descent (throttles still in the cruise thrust position), switch the engine synchronization to OFF, then begin the descent. This procedure will prevent the system from driving to its limit and breaking while attempting to maintain synchronized operation as the throttles go toward the idle position. It is extremely important that this sequence of operation be followed. The engine sync switch is to remain off for the remainder of the flight.
Turbine Engine Monitoring Program
Continental’s Flight Operations Engineering and Propulsion Engineering share engine and airframe performance data generated by the flight crews and transmitted via ACARS or T.E.M.P. log (Turbine Engine Monitoring Program). From this data, engine trend analysis and airframe performance deterioration in the form of excess drag are assessed. Appropriate maintenance action is initiated where indicated.
Amplified Procedures
On flights of one hour and over, an engine data report will be sent via ACARS or a T.E.M.P. log will be completed.
With the aircraft stabilized at the desired cruise speed, disengage the autopilot and retrim the aircraft. Re-engage the autopilot.
The autothrottles, wing anti-ice, engine anti-ice, and fuel heat must be off and the A/C allowed to stabilize for three (3) minutes prior to recording data. Do not re-adjust EPRs.
Maintain the following conditions for at least three (3) minutes.
.
MACH + .005
.
ALT + 50 ft.
.
TAT + 1°
.
EPR + 0.02
Record only the Captain’s MACH, IAS, and ALT, but compare with the First Officer’s instruments for allowable tolerances. If the Captain’s and First Officer’s flight instruments differ by the following values, an entry should be made in the maintenance log book.
.
MACH ±0.010
.
ALT ±100ft.
.
IAS ±4K
Although these tolerances may be within maintenance manual limits, the squawks will be noted when Flight Operations Engineering prepares their quarterly cruise monitoring report and will aid in the investigation of chronic fuel burn problems.
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