Chapter 15-Transition to Jet Powered Airplanes

Table of Contents
General
Jet Engine Basics
Operating the Jet Engine
Jet Engine Ignition
Continuous Ignition
Fuel Heaters
Setting Power
Thrust to Thrust Lever Relationship
Variation of Thrust with RPM
Slow Acceleration of the Jet Engine
Jet Engine Efficiency
Absence of Propeller Effect
Absence of Propeller Slipstream
Absence of Propeller Drag
Speed Margins
Recovery from Overspeed Conditions
Mach Buffet Boundaries
Low Speed Flight
Stalls
Drag Devices
Thrust Reversers
Pilot Sensations in Jet Flying
Jet Airplane Takeoff and Climb
V-Speeds
Pre-Takeoff Procedures
Takeoff Roll
Rotation and Lift-Off
Initial Climb
Jet Airplane Approach and Landing
Landing Requirements
Landing Speeds
Significant Differences
The Stabilized Approach
Approach Speed
Glidepath Control
The Flare
Touchdown and Rollout




ROTATION AND LIFT-OFF

Rotation and lift-off in a jet airplane should be considered a maneuver unto itself. It requires planning, precision, and a fine control touch. The objective is to initiate the rotation to takeoff pitch attitude exactly at VR so that the airplane will accelerate through VLOF and attain V2 speed at 35 feet at the end of the runway. Rotation to the proper takeoff attitude too soon may extend the takeoff roll or cause an early lift-off, which will result in a lower rate of climb, and the predicted flightpath will not be followed. A late rotation, on the other hand, will result in a longer takeoff roll, exceeding V2 speed, and a takeoff and climb path below the predicted path.

Each airplane has its own specific takeoff pitch attitude which remains constant regardless of weight. The takeoff pitch attitude in a jet airplane is normally between 10 and 15 nose up. The rotation to takeoff pitch attitude should be made smoothly but deliberately, and at a constant rate. Depending on the particular airplane, the pilot should plan on a rate of pitch attitude increase of approximately 2.5 to 3 per second.

In training it is common for the pilot to overshoot VR and then overshoot V2 because the pilot not flying will call for rotation at, or just past VR. The reaction of the pilot flying is to visually verify VR and then rotate. The airplane then leaves the ground at or above V2. The excess airspeed may be of little concern on a normal takeoff, but a delayed rotation can be critical when runway length or obstacle clearance is limited. It should be remembered that on some airplanes, the all-engine takeoff can be more limiting than the engine out takeoff in terms of obstacle clearance in the initial part of the climb-out. This is because of the rapidly increasing airspeed causing the achieved flightpath to fall below the engine out scheduled flightpath unless care is taken to fly the correct speeds. The transitioning pilot should remember that rotation at the right speed and rate to the right attitude will get the airplane off the ground at the right speed and within the right distance.




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PED Publication