Stabilized approach
It seems obvious that any approach to landing should be stabilized, however, this issue arises again and again during investigations and recommendations development. Let's try to understand it too.
Stabilized approach
Reading Time: ~8-10 minutes
Unstabilized approaches to landing indeed constitute a significant issue in the field of aviation safety.
The majority of quantitative data, including reports from Flight Safety Foundation and other research organizations, indicate that a large percentage of aviation incidents and accidents are associated with unstabilized approaches to landing. This emphasizes the importance of maintaining a stabilized approach as a critical factor in ensuring flight safety.
The majority of quantitative data, including reports from Flight Safety Foundation and other research organizations, indicate that a large percentage of aviation incidents and accidents are associated with unstabilized approaches to landing. This emphasizes the importance of maintaining a stabilized approach as a critical factor in ensuring flight safety.
Article Contents
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
Competencies related to executing approach and landing
The ICAO Doc.9995, also known as the "Manual of Evidence-based Training," was developed by the International Civil Aviation Organization (ICAO) to improve the effectiveness and safety of aviation training.
This document is a guide to Evidence-Based Training (EBT), detailing specific training methods and a set of competencies that every pilot should develop.
The stabilized approach to landing is closely related to the competencies described in Doc.9995, as many of these competencies directly pertain to the execution of this crucial maneuver.
It's worth noting which competencies might be applicable in the context of executing a stabilized approach to landing:
This document is a guide to Evidence-Based Training (EBT), detailing specific training methods and a set of competencies that every pilot should develop.
The stabilized approach to landing is closely related to the competencies described in Doc.9995, as many of these competencies directly pertain to the execution of this crucial maneuver.
It's worth noting which competencies might be applicable in the context of executing a stabilized approach to landing:
- Application of KnowledgeUsing theoretical knowledge about aerodynamics, meteorology, and flight procedures to perform a stabilized approach1
- Application of ProceduresApplying procedures in accordance with SOPs and existing rules, utilizing relevant knowledge2
- Flight Management - Manual & AutomaticUnderstanding and performing standard landing procedures, including stabilized approach in manual and automatic modes3
- Workload ManagementAssessing and being able to manage the number of tasks required to be executed during the approach to landing4
- CommunicationThe necessity to convey information and ensure that this information is accurately received5
- Leadership and TeamworkThe ability to work effectively within a team, share information, and coordinate actions6
- Problem Solving and Decision MakingEvaluating and interpreting the flight situation to decide whether to continue the approach or abort the landing7
- Situational
AwarenessAssessing and understanding the current and future position of the aircraft relative to the runway and other potential obstacles8
Using a competency-based approach to pilot training helps to develop the necessary skills and knowledge for the safe and effective conduct of flights, including a stabilized approach to landing.
Since the execution of an approach to landing, and the conditions under which such an approach is considered stabilized, is a set of correctly performed procedures, it is this competency that will help the pilot to be more efficient and safe at all stages of flight.
Since the execution of an approach to landing, and the conditions under which such an approach is considered stabilized, is a set of correctly performed procedures, it is this competency that will help the pilot to be more efficient and safe at all stages of flight.
Fundamentals of a stabilized approach
All approaches should be stabilized.
Execution of go-around is not a sign of low professionalism.
Execution of go-around is not a sign of low professionalism.
A stabilized approach is an important procedure used in aviation that ensures the safety and precision of an aircraft landing. A stabilized approach assumes that all key flight parameters of an aircraft (such as speed, altitude, direction, and descent rate) remain constant or change very slowly and predictably.
In accordance with Federal Aviation Rules of Russian Federation #128 and 3.90:
The PIC (Pilot in Command) must discontinue the descent and execute a missed approach (go-around) if:
In accordance with Federal Aviation Rules of Russian Federation #128 and 3.90:
The PIC (Pilot in Command) must discontinue the descent and execute a missed approach (go-around) if:
1
dangerous meteorological phenomena are observed
2
flocks of birds posing a threat to landing safety are present
3
engine power mode needs to be increased more than nominal to maintain the descent gradient on the glide slope, unless otherwise provided by the aircraft flight manual
4
the decision altitude warning and/or ground proximity warning activated before establishing a reliable visual contact with approach lights or other landing course landmarks
5
the approach is not stabilized as per the requirements stated in the company's Standard Operating Procedures (SOP) at an altitude of 300 meters above aerodrome level during instrument meteorological conditions or at an altitude of 150 meters during visual meteorological conditions, unless otherwise stated in the aircraft flight manual
6
visual contact with the approach lights (runway lights) or ground landmarks is not established by the time the aircraft reaches DA/H during a precision approach or an approach with vertical guidance
7
during a non-precision approach in instrument meteorological conditions, visual contact with the approach lights (runway lights) or ground landmarks is not established by the time the aircraft reaches the missed approach point
8
the aircraft's position in space or its movement parameters relative to the runway do not ensure a safe landing
9
visual contact with the approach lights (runway lights) or ground landmarks is lost when descending below DA/H or MDA/H
10
obstacles posing a threat to flight safety have appeared in the airspace or on the runway
11
the landing calculation does not ensure a safe landing
As complying with the stabilized approach requirement is mandatory when approaching for landing, it's time to discuss what constitutes the recommended elements of a stabilized approach?
An approach is considered stabilized when the criteria defined in the aircraft flight manual or the company's SOP are established at the appropriate altitude and maintained throughout the remainder of the approach.
In accordance with Stabilized Approach - ALAR Tool Kit - Flight Safety Foundation, Standard Operating Procedures of airlines and FAR these heights are permanent:
- 1000 FEETabove runway level in
Instrument Meteorological Conditions (IMC). - 500 FEET
above runway level in
Visual Meteorological Conditions (VMC).
It's important to remember that the goal of the approach is not to stabilize at a particular altitude, but to manage the aircraft's energy and trajectory in such a way that it remains within the limits of the stabilized approach conditions throughout the entire approach.
Criteria for a stabilized approach
The aircraft is on a trajectory provided by the appropriate guidance system, which has been set up and identified, or if the flight is performed visually - on a trajectory that ensures a safe reach of the runway relative to ground obstacles.
Only minor changes in heading and pitch are required to maintain the given trajectory.
The aircraft maintains the established approach speed (Vapp). Deviations of up to +10…-5 knots from Vapp are allowed.
It should be noted that pilots often read "+10...-5" as the speed limit. No, the speed should be Vapp.
Deviations are allowed when there is a trend to return to Vapp!
It should be noted that pilots often read "+10...-5" as the speed limit. No, the speed should be Vapp.
Deviations are allowed when there is a trend to return to Vapp!
The necessary landing configuration is established.
The vertical descent speed (Vy) does not exceed 1000 feet/min.
If the approach conditions require maintaining an increased vertical speed due to a steep glide slope angle or significant tailwind, this should be addressed additionally (during the pre-landing briefing).
Engines are operating at a mode corresponding to the chosen landing configuration.
All briefings and checklist cards have been completed.
Special Types of Approaches
Specific types of approaches are considered stabilized if the following conditions are met:
- When performing an ILS or GLS approach, course and glide slope deviations should not exceed one dot (or half of the extended course deviation scale).
- When performing a circling approach, the aircraft must be brought out of the bank on the final approach course before reaching an altitude of 300 feet above the airport.
- When performing a visual approach (or the visual part of an instrument approach), the aircraft's vector of continued motion at an altitude of 100 feet above the runway end should not exceed the runway's width.
What else is important?
If the situation unfolds in such a way that maintaining the standard criteria for a stabilized approach is impossible today, under these conditions, the crew should at the very least:
Take note of the possibility of deviation from the standard criterion
01Assess the risks of this deviation
02Define reasonable boundaries for the deviation
03- Define the procedure for interaction in this new, non-standard situation04
Not all pilots understand the need for additional discussion.
But put yourself in the shoes of the Pilot Monitoring, who isn't required to be able to read your thoughts. They have their own duties on this flight - to notice an exceeding of the stabilized approach criteria and announce "UNSTABILIZED, GO AROUND!"
That's why the success of the approach depends on how equally you both understand the specifics of the upcoming approach.
To improve situational awareness, our company has adopted preventive call-outs, which the PM must give in case of deviation from stabilization conditions.
But put yourself in the shoes of the Pilot Monitoring, who isn't required to be able to read your thoughts. They have their own duties on this flight - to notice an exceeding of the stabilized approach criteria and announce "UNSTABILIZED, GO AROUND!"
That's why the success of the approach depends on how equally you both understand the specifics of the upcoming approach.
To improve situational awareness, our company has adopted preventive call-outs, which the PM must give in case of deviation from stabilization conditions.
Preventive call-outs
Why are they even needed?
For enhancing situational awareness, preventive call-outs are accepted in all companies, which the Pilot Monitoring should provide in case of deviation from the stabilization conditions.
After receiving a preventive call-out, the Pilot Flying should confirm the information ("CHECKED") and apply a corrective action.
For instance, if the instrument speed deviates from the set one, Pilot Monitoring can announce "SPEED" or "SPEED LOW/SPEED HIGH" depending on the company and requirements.
After receiving a preventive call-out, the Pilot Flying should confirm the information ("CHECKED") and apply a corrective action.
For instance, if the instrument speed deviates from the set one, Pilot Monitoring can announce "SPEED" or "SPEED LOW/SPEED HIGH" depending on the company and requirements.
Pilot Monitoring can also use the basic call-outs to warn the Pilot Flying about the situation's development if the approach remains within the stabilization conditions, but there is no trend towards returning to the calculated parameters over a noticeable period of time.
If Pilot Monitoring believes that the approach has become unstabilized below the stabilization altitude due to deviations in piloting techniques or unsafe weather conditions, they should clearly state: "UNSTABILIZED". The Pilot Flying should begin the go-around maneuver regardless of their own belief that the aircraft can successfully land.
If Pilot Monitoring believes that the approach has become unstabilized below the stabilization altitude due to deviations in piloting techniques or unsafe weather conditions, they should clearly state: "UNSTABILIZED". The Pilot Flying should begin the go-around maneuver regardless of their own belief that the aircraft can successfully land.
Big summary
An unstabilized approach is an undesirable aircraft state that can only be corrected by executing a missed approach or going around.
According to IATA, 15% of landing accidents could have been prevented by going around.
Refusing to go around from an unstabilized approach or an approach that becomes unstable is an intentional violation of standard operating procedures (SOP).
Understanding why procedures are violated is a complex task in the field of human factors. Often, it may seem that a temporary violation of SOP does not produce negative results, and therefore a pilot may develop non-compliant behavior. Therefore, it is important for pilots to understand what is at risk with an unstabilized approach.
Incident analysis shows that a stabilized approach to a certain gate (chosen by the operator, for instance, 6 or 10 miles away from the touchdown point on the runway) is a safe altitude to assess the aircraft's energy.
If the criteria for the gate are not met and the crew continues the approach - it carries the excess (or deficiency) of energy to an unsafe altitude. In emergency situations, when other unforeseen conditions are encountered, the decision to reject the landing and go around at a lower than the established altitude may be too late to perform a safe go-around.
Crews should feel completely comfortable and confident when performing a go-around from any position during approach and landing, up to the touch down on the runway.
This requires training and practice, as much as possible, in simulator training, because this maneuver is rarely performed on regular flights. It also requires the development of a corporate culture where go-arounds are not frowned upon but are not used as a catalyst or punishment for the crew.
Also, it is important to maintain a culture of compliance with all SOPs. Compliance with procedures regarding the stabilized approach policy can be easily monitored with objective control means or LOSA flights, which we discussed in one of our previous articles.
And the most important thing to remember:
According to IATA, 15% of landing accidents could have been prevented by going around.
Refusing to go around from an unstabilized approach or an approach that becomes unstable is an intentional violation of standard operating procedures (SOP).
Understanding why procedures are violated is a complex task in the field of human factors. Often, it may seem that a temporary violation of SOP does not produce negative results, and therefore a pilot may develop non-compliant behavior. Therefore, it is important for pilots to understand what is at risk with an unstabilized approach.
Incident analysis shows that a stabilized approach to a certain gate (chosen by the operator, for instance, 6 or 10 miles away from the touchdown point on the runway) is a safe altitude to assess the aircraft's energy.
If the criteria for the gate are not met and the crew continues the approach - it carries the excess (or deficiency) of energy to an unsafe altitude. In emergency situations, when other unforeseen conditions are encountered, the decision to reject the landing and go around at a lower than the established altitude may be too late to perform a safe go-around.
Crews should feel completely comfortable and confident when performing a go-around from any position during approach and landing, up to the touch down on the runway.
This requires training and practice, as much as possible, in simulator training, because this maneuver is rarely performed on regular flights. It also requires the development of a corporate culture where go-arounds are not frowned upon but are not used as a catalyst or punishment for the crew.
Also, it is important to maintain a culture of compliance with all SOPs. Compliance with procedures regarding the stabilized approach policy can be easily monitored with objective control means or LOSA flights, which we discussed in one of our previous articles.
And the most important thing to remember:
IF IN DOUBT - GO AROUND!
Fly safe and see you next Thursday!
Name of article: Stabilized approach
Release date: 6/15/2023
Acrticle author: Georgii Kurbatskii
Release date: 6/15/2023
Acrticle author: Georgii Kurbatskii
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