STABILISED APPROACHES

Stabilized Approach: General Considerations

"A safe and good landing starts with the approach" is what has been taught to us at the flying school stage. This does not change with change on to bigger and faster aircraft. A stabilised approach is a concept that would generally lead to a safe landing. One must not attempt to land of an unstabilised approach, as unstabilised approaches have been known to have caused many a landing accident - in India, the fatal accidents at Mangalore (AI Express) and Patna (Alliance Air) have been caused as a result of continuing to persist with landing of an unstabilised approach. It is now an accepted fact that the decision to execute a go-around is no indication of poor performance. Of course a go-around on every approach cannot become a norm. Every approach has to be planned and briefed so that it is stabilised.

Since a stabilised approach is key to a safe landing, every company, in its operations manual lays down the criteria that constitute a stabilised approach. The SOPs further lay down the procedure to be followed by the PF and PM in case the approach is not stabilised. What is a stabilised approach?

Maintaining a stable speed, descent rate, and vertical/lateral flight path in landing configuration is commonly referred to as the stabilized approach concept. Any significant deviation from planned flight path, airspeed, or descent rate should be announced.

Note: Do not attempt to land from an unstable approach; go-around at or before the checkpoint.

Recommended Elements of a Stabilized Approach

The following recommendations are consistent with criteria developed by the Flight Safety Foundation. All approaches should be stabilized by 1,000 feet AFE in instrument meteorological conditions (IMC) and by 500 feet AFE in visual meteorological conditions (VMC). An approach is considered stabilized when all of the following criteria are met:

• The airplane is on the correct flight path
•  Only small changes in heading and pitch are required to maintain the correct flight path
• The airplane speed is not more than VREF + 20 knots indicated airspeed and not less than Vref
• The airplane is in the correct landing configuration
• Sink rate is no greater than 1,000 fpm; if an approach requires a sink rate greater than 1,000 fpm, a special briefing should be conducted
• Thrust setting is appropriate for the airplane configuration
• All briefings and checklists have been conducted.
• Specific types of approaches are stabilized if they also fulfil the following:
• ILS approaches should be flown within one dot of the glide slope and localizer
• During a circling approach, wings should be level on final when the airplane reaches 300 feet AFE.
• Unique approach procedures or abnormal conditions requiring a deviation from the above elements of a stabilized approach require a special briefing.

Note: An approach that becomes un-stabilized below 1,000 feet AFE in IMC or below 500 feet AFE in VMC requires an immediate go-around. Also, stabilised conditions should be maintained throughout the rest of the approach for it to be considered a stabilized approach. If the above criteria cannot be established and maintained at and below 500 feet AFE, initiate a go-around.