Reviewer:

Capt. Muammar Reza Nugraha
(Director of Legal, Professional and Government Affair Committee Ikatan Pilot Indonesia)

Flight safety and security are always a priority for pilots in carrying out flying tasks.During the aircraft operations,there are several critical phases : the take-off run, the take-off flight path, the final approach, the missed approach, the landing, including the landing roll, and other flight phases under responsibility by the pilot-in- command.[1] These phases require proper anticipation, detection, correction, and appropriate decision-making so that flight safety can be maintained.

This article will discuss the stabilized approach recommendations from the Flight Safety Foundation, an independent organization that aims to provide world aviation safety references and guidelines, this article is not intended to supersede the flight rules in the company or the applicable country's flight rules.

According to IATA data unstabilized approach per 1000 operations, when compared to before the pandemic, during the first half of 2020. Stabilized approach is a crucial factor in reducing the possibility of runway excursion, hard landing, and other possible accidents [2.] The data identifies potential areas of concern in flight safety, as flight frequencies increase [3].

Stabilized Approach

Stabilized Approach is an Approach phase condition that meets all criteria in the standard operating procedure (SOP) before or when it reaches the applicable minimum stabilized approach altitude, i.e.:

• 1,000 feet above airport elevation in instrument meteorological conditions (IMC); or,

• 500 feet above airport elevation in visual meteorological conditions (VMC). Recommended Elements of a Stabilized Approach. An approach is stabilized when all of the following criteria are met:

1. The aircraft is on the correct flightpath;
2. Only small changes in heading/pitch are required to main-tain the correct flight path;
3. The aircraft speed is not more than VREF + 20 kt indicated airspeed and not less than VREF;
4. The aircraft is in the correct landing configuration;
5. 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;
6. Power setting is appropriate for the aircraft configuration and is not below the minimum power for approach as de-fined by the aircraft operating manual;
7. All briefings and checklists have been conducted;
8. Specific types of approaches are stabilized if they also fulfill the following: instrument landing system (ILS) approaches must be flown within one dot of the glideslope and localizer; a Category II or Category III ILS approach must be flown within the expanded localizer band; during a circling approach, wings should be level on final when the aircraft reaches 300 ft above airport elevation; and,
9. Unique approach procedures or abnormal conditions requiring a deviation from the above elements of a stabilized approach require a special briefing. An approach that becomes unstabilized below 1,000 ft above airport elevation in IMC or below 500 ft above airport elevation in VMC requires an immediate go- around. At the minimum stabilization height and below, a call should be made by the pilot not flying/pilot monitoring (PNF/PM) if any flight parameter exceeds the established criteria. Any time an approach is not stabilized at the minimum sta-bilization height or becomes unstabilized below the minimum stabilization height, a go-around should be conducted [4].

Contributing Factors affecting the Unstabilized Approach:

• Fatigue;
• Pressure of flight schedule (making up for delays);
• Any crew-induced or ATC-induced circumstances result-ing in insufficient time to plan, prepare and conduct a safe approach. This includes accepting requests from ATC to fly higher/faster or to fly shorter routings than desired;
• ATC instructions that result in flying too high/too fast during the initial approach;
• Excessive altitude or excessive airspeed (e.g., inadequate energy management) early in the approach;
• Late runway change (lack of ATC awareness of the time re-quired by the flight crew to reconfigure the aircraft for a new approach);
• Excessive head-down work (e.g., flight management system [FMS] reprogramming);
• Short outbound leg or short downwind leg (e.g., because of traffic in the area);
• Late takeover from automation (e.g., because the autopilot [AP] fails to capture the glideslope);
• Premature descent or late descent caused by failure to posi-tively identify the final approach fix (FAF);
• Inadequate awareness of wind conditions, including:
  • Tail wind component;
  • Low-altitude wind shear;
  • Local wind gradient and turbulence (because of terrain or buildings); or,
  • Recent weather along the final approach path (e.g., wind shift or downdrafts caused by a descending cold air mass following a rain shower);
  • Incorrect anticipation of aircraft deceleration characteristics in level flight or on a three-degree glide path;
  • Failure to recognize deviations or failure to adhere to the excessive parameter-deviation limits;
  • Belief that the aircraft will be stabilized at the minimum sta-bilization height or shortly thereafter;
  • Excessive confidence by the PNF/PM that the pilot flying (PF) will achieve a timely stabilization;
  • PF-PNF/PM too reliant on each other to call excessive devia-tions or to call for a go-around; and,
  • Visual illusions [4].

Deviations that often occured during the unstabilized approach:

• Entire approach flown at idle thrust down to touchdown, because of excessive airspeed and/or excessive altitude from early in the approach;Steep approach (above desired flight path with excessive ver-tical speed). Steep approaches are conducted typically twice as often as shallow approaches
• Shallow approach (below desired glide path)
• Low-airspeed maneuvering (energy deficit)
• Excessive bank angle when capturing the final approach course
• Activation of the ground-proximity warning system (GPWS) or the terrain awareness and warning system (TAWS)3:
• Mode 1: “sink rate”
• Mode 2A: “terrain” (not full flaps)
• Mode 2B: “terrain” (full flaps)
• Late extension of flaps, or flaps-load-relief-system activation resulting in the late extension of flaps

Excessive flight-parameter deviation when crossing the minimum stabilization height:

• Excessive airspeed
• Not aligned with runway
• Excessive bank angle
• Excessive vertical speed
• Flight path above glideslope
• Excessive bank angle, excessive sink rate or excessive maneu-vering while conducting a side-step maneuver
• Speed brakes remain extended on short-final approach
• Excessive flight-parameter deviation down to runway threshold
• High at runway threshold crossing (i.e., more than 50 feet above threshold)
• Extended flare and extended touchdown [4] .

Prevention of Unstable Approaches

Prevention of Unstabilized Approachby can be done by enhancing safety ethics with implementing Anticipate, Detecting, Correction, and Decision making.

Anticipate

Some factors likely to result in an unstabilized approach can be anticipated. For example, pilots and controllers should avoid situations that result in rushing approaches. The approach briefing provides opportunities to identify and discuss factors such as nonstandard altitude, airspeed restrictions and energy management. The flight crew should agree on the man-agement of the descent, deceleration and stabilization. This agree-ment will constitute a common objective for the PF and PNF/PM.

Detect

The purpose of defined excessive-parameter-deviation limits and minimum stabilization heights is to provide the PF and PNF/PM with a common reference for effective monitoring (early detection of deviations) and backup (timely and precise calls for effective corrections). To ensure monitoring and backup, the following should be avoided:

• Late briefings
• Unnecessary radio calls (e.g., company calls)
• Unnecessary actions (e.g., use of airborne communications addressing and reporting system [ACARS])
• Nonpertinent conversations on the flight deck (i.e., breaking the “sterile cockpit rule”4).

Reducing workload and flight deck interruptions/distractions also allows the flight crew to:

• Better cope with fatigue
• Comply with an unexpected ATC request (e.g., runway change)
• Adapt to changing weather conditions
• Manage a system malfunction (e.g., flaps jamming or landing gear failing to extend).

Correct

Positive corrective actions should be taken before deviations develop into a challenging situation or a hazardous situation in which the only safe action is a go-around. Corrective actions may include:

• The timely use of speed brakes or landing gear to correct excessive height or excessive airspeed; and,
• Extending the outbound leg or downwind leg. Decide

If the approach is not stabilized before reaching the minimum stabilization height, or if any flight parameter exceeds deviation limits (other than transiently) when below the minimum stabili-zation height, a go-around must be conducted immediately.

Implementing the safety ethics mentioned above is expected to increase awareness as follows:

• Horizontal awareness, by closely monitoring the horizontal flight path
• Vertical awareness, by monitoring the vertical flight path and the rate of descent
• Airspeed awareness, by monitoring airspeed trends [4].

Handling of Unstable Approach events:

Following the positive safety culture (just culture) in world aviation, the handling of incidents/accidents aims to improve safety by investigating and making recommendations so that the incident does not recur and can be recognized for all possible causes to be corrected and improved safety in the future.

Just Culture in the context of aviation is also considered as one of the factors that can improve personnel safety awareness and performance, and prevent accidents or incidents caused by human factors, which is one of the main causes of accidents or incidents in aviation.

Human factors is a term that refers to aspects related to humans, such as cognition, motivation, emotion, communication, cooperation, leadership, and culture [5].

The use of technology in flight data analysis is based in a NON-PUNITIVE manner following:

Annex 19 Appendix 3

States shall ensure that safety data or safety information is not used for:

1. disciplinary, civil, administrative, and criminal proceedings against employees, operational personnel, or organizations.
2. disclosure to the public; or c) any purposes other than maintaining or improving safety; And additionally, compels the State to ensure that a formal procedure to provide protection to safety data, safety information and related sources is established [6].

Along with Annex 19, the ICAO Safety Management Manual (Doc 9859) contains guidelines for the establishment of both mandatory and voluntary safety reporting systems. Properly collected and expertly analysed aviation safety information is a powerful and necessary resource for any organisation. It is intended to be used solely for safety improvement and can cause extensive harm if used improperly, as in these examples [7].

1. Job sanctions or penalties by employers
2. Penalties imposed by Government regulators or judiciaries based upon the safety information
3. Public disclosure of the information
4. Criminal sanctions based on the safety information
5. Misuse of the safety information in civillitigation[8].

CASR 91

C.2 SAFETY DATA AND SAFETY INFORMATION ANALYSIS 19.65 Flight Data Analysis Program.

C. flight data analysis program shall be non-punitive and contain adequate safeguards to protect the source(s) of the data [9].

All investigations and results go through a process that is in line with Aviation Law No. 1 of 2009, CASR, and International Standards and Recommended Practices Annex 19 to the Convention on International Civil Aviation regarding the Safety Management System. The procedure for handling incidents that do not go through the process of applicable rules and in a punitive way will lead to the reversal of the aviation safety culture that has been maintained and developed.

Bibliography

1. EASA Regulation (EU) No965/2012, Annex Definitions
2. IFALPA Safety Buletin 20SAB06 2020 “Unstable Approaches during Reduced Operations”
3. IATA Operations Notice Number: 002/2020.
4. FSF ALAR Briefing Note 7.1, November 2000, — Stabilized Approach
5. Menumbuhkan Just Culture : Sumber Daya Manusia dalam Tata Kelola Maskapai Penerbangan, Ainul Gara, 2023
6. IFALPA, position paper 21POS12 2021, Positive Safety Culture
7. Annex19 appendix 3, ICAO
8. Annex19, the ICAO Safety Management Manual (Doc9859)
9. CASR 91