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Stabilized Constant Descent Angle NPA’s. Overview. What is a Stabilized Constant Descent Angle (SCDA) Non- Precision Approach (NPA)? Why do we need it? How do we fly it? Considerations?. Legal-Applicability. CBAAC No. 0238 applicable to operators under Subparts 703, 704 and 705
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Overview • What is a Stabilized Constant Descent Angle (SCDA) Non- Precision Approach (NPA)? • Why do we need it? • How do we fly it? • Considerations?
Legal-Applicability • CBAAC No. 0238 • applicable to operators under Subparts 703, 704 and 705 • Ops Spec 019, 303, or 503 • use the Minimum Descent Altitude (MDA) as a Decision Altitude (Height) DA(H).
SCDA Training Program • The operator should ensure that flight crews receive ground and simulator or flight training that addresses SCDA NPA procedure proficiency. • The operator should have SOPs incorporating SCDA NPA procedures.
Background • Precision Approach • An approach with both lateral and vertical information used to guide the aircraft to a Decision Height • Non Precision Approach • An approach with only lateral information used to guide the aircraft to a minimum descent altitude
Background • Stabilized approach • means a final approach flown to achieve a constant rate of descent, at an approximate 3 degree descent flight path angle, with stable airspeed, power setting, and attitude, with the aircraft configured for landing.
What is a SDCA? • means stabilized constant-descent-angle non-precision approach.
Traditional NPA • Dive and Drive
The Approach • Initial Approach • From the IAF to the IF (if defined) • Obstacle clearance 1,000 ft. • Intermediate Approach • From the IF to the FAF • Obstacle clearance 500 ft. • Final Approach • From the FAF to the MDA • Obstacle clearance 200 ft.
Traditional NPA FAF Final Approach Segment 3.3 nm
Constant Descent Final Approach FAF Final Approach Segment 3.3 nm
Advantages of the SDCA • Increased safety by employing the concepts of stabilized approach criteria and procedure standardization. • Improved pilot situational awareness (SA) and reduced pilot workload. • Improved fuel efficiency by minimizing the low-altitude level flight time.
Advantages of the SDCA • Reduced noise level by minimizing the level flight time at high thrust settings. • Procedural similarities to precision approach operations. • Reduced probability of infringement on required obstacle clearance during the final approach segment.
Statistics* *Flight Safety Foundation Approach and Landing Accident Reduction Task Force
Stabilized Approach • Aircraft on the correct flight path • Only minor changes required to maintain the correct flight path • Airspeed between Vref and Vref +20 and power properly set • Aircraft properly configured for landing • Sink rate no greater than 1,000 fpm • All briefings and checklists complete
SDCA Criteria • The approach is flown to straight-in minima. • The approach design should permit a final approach segment descent angle of 2.9 to 3.5 degrees. • The final approach course shall not be more than 15 degrees from runway centreline.
Approach Considerations • Don’t forget temperature corrections • Take minimum altitudes at step-down fixes into account when planning the final descent angle
Missed Approach • When flown correctly, the position where a missed approach is commenced following an SCDA NPA to MDA will occur before the published MAP. • The missed approach climb will normally occur some distance before reaching the published MAP.
Missed Approach • Missed approach can begin before the MAP • Missed approach must begin at the MAP • For obstacle clearance, delay any turns stated in the published missed approach procedure until the aircraft crosses the MAP
Missed Approach • Time required for a decision (reaction time); • Rate of descent at commencement of the missed approach; • Pilot technique; • Aircraft performance; and • Baro altimeter lag.