The Stabilized Approach.

For several years the highest percentage of incidents and accidents has occurred during the approach and landing phases. According to a Flight Safety Foundation study, 46 percent of the 250 worldwide accidents of the period 2002-2011 happened during approach, landing or go-around.

Although operators can specify different minimums criteria for deciding to continue the approach or execute a go-around, on their Approach and Landing Accident Reduction (ALAR) Briefing Note 7-1, the FSF suggests that the approach must be stabilized 1000ft. AGL on IMC and 500ft AGL on VMC. An approach is considered stabilized when:

• The aircraft is on the correct flight path.
• Only small changes on heading and pitch are necessary to maintain the correct flight path.
• The airspeed is not more than VREF + 20 IAS and not less than VREF.
• The aircraft is on the landing configuration.
• Sink rate is not more than 1000ft/min. If an approach requires a sink rate of more than 1000ft/min, should be noted on the approach briefing.
• Power/Thrust is appropriate for the actual aircraft configuration and not below the minimum required for the approach according to the AOM.
• Approach briefing and all necessary checklists have been conducted.
• Specific type of approaches are stabilized if they also fulfill the following
• ILS approaches should be flown within one dot of the localizer and glide slope.
• A category II or III approach must be flown within the expanded localizer band.
• During a Circling Approach wings should be level on final when the aircraft reaches 300ft above airport elevation.
• Unique approach conditions or abnormal conditions requiring a deviation from the above elements of a stabilized approach require a special briefing.

Stabilised Approach Gates

Stabilized Approach “Gates”

If anyone of these elements are not met by 1000ft above airport elevation on IMC or 500ft above airport elevation on VMC, requires and immediate GO-AROUND.

Contributing factors to create an unstabilised approach can be adverse weather, being placed by ATC in an uncomfortable position for the approach, runway illusions during a night approach with no vertical guidance, being high or too close to the runway during a circling maneuver.

Continuation of an unstabilized approach can lead to several situations like; cross the runway threshold too fast and/or too high, not be aligned with the runway centerline, leading to land long on the existing runway, or a runway excursion.

Build your own defenses; adhere strictly to SOP’s and if for some reason not listed here you don’t feel comfortable with the approach execute a go-around, prepare for a new approach and start again. Don’t allow anyone to rush you.
Happy Landings!!

 

Capt. Ivan

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