.
Being fast and/or high on approach: 30 % of events.
Aircraft Energy Level
The level of energy of an aircraft is a function of the following primary flight parameters and of their rate of change (trend):
.
Airspeed and speed trend;
.
Altitude and vertical speed (or flight path angle);
.
Drag (i.e., drag caused by speed brakes, slats/flaps and/or landing gear); and,
.
Thrust level.
One of the tasks of the pilot is to control and monitor the energy level of the aircraft (using all available cues) in order to:
.
Maintain the aircraft at the appropriate energy level for the flight phase and configuration:
- flight path, speed and thrust; or,
.
Recover the aircraft from a low energy or high energy situation, i.e., from:
-being too slow and/or too low; or,
-being too fast and/or too high.
Energy Management during Approach
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AIRBUS INDUSTRIE
Flight Operations Support
Controlling the aircraft energy level implies balancing the airspeed, thrust (and drag) and flight path, or transiently trading one parameter for another.
Autopilot and flight director modes, aircraft instruments, warnings and protections are designed to relieve or assist the flight crew in these tasks.
Going Down and Slowing Down :
How Fast Can you Fly Down to the Marker?
A study by the U.S. NTSB acknowledges that maintaining a high airspeed down to the outer marker (OM) does not favor the capture of the glideslope beam by the autopilot or the aircraft stabilization at the defined stabilization height.
The study concludes that no speed restriction should be imposed when within 3 nm to 4 nm before the OM, mainly in instrument meteorological conditions (IMC).
Nevertheless, ATC requests for maintaining a high airspeed down to the marker (160 kt to 200 kt IAS typically) are frequent at high-density airports, to increase the landing rate.
The purpose of the following part is to:
.
Recall the definition of stabilization heights;
.
Illustrate the aircraft deceleration characteristics in level flight and on a 3-degree glide path; and,
.
Provide guidelines for assessment of the maximum speed which, reasonably, can be maintained down to the marker, as a function of:
-the distance from the OM to the runway threshold; and,
- the desired stabilization height.
Stabilization height:
The definition and criteria for a stabilized approach are defined in Briefing Note 7.1 -Flying Stabilized Approaches.
Getting to Grips withApproach-and-Landing Accidents Reduction
The minimum stabilization height should be:
.
1000 ft above airfield elevation in IMC;
.
500 ft above airfield elevation in VMC.
Airlines usually require flight crews to cross the outer marker (i.e., typically between 1500 ft and 2000 ft above airfield elevation) with the aircraft configured in the landing configuration.
This allows time, before reaching the applicable stabilization height, for:
.
Stabilizing the final approach speed; and,
.
Completing the landing checklist.
Aircraft deceleration characteristics:
Although deceleration characteristics largely depends on the aircraft type and gross-weight, the following typical values can be considered for a quick assessment and management of the aircraft deceleration capability:
. Deceleration in level flight:
- with approach flaps extended:
.. 10 to 15 kt-per-nm;
- during extension of gear and landing flaps:
.. 20 to 30 kt-per-nm;
. Deceleration on a 3-degree glide path: 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：Getting to Grips with Approach-and-Landing Accidents Reducti(86)
