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.
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.
- ALAR Briefing Note 7.1 – Stabilized Approach
- ALAR Briefing Note 8.1 – Runway Excursions and Overruns
- Reducing the Risk of Runway Excursions – Report of the Runway Safety Initiative
- Runway Excursion Risk Awareness Tool
- Non-stabilized Approach After ATC-Requested Runway Change (OGHFA SE)
- Runway Overrun On Landing (OGHFA SE)
- Copies of the FSF ALAR Toolkit on CD may be obtained from the Flight Safety Foundation