Flying a Visual Approach
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|Content source:||Flight Safety Foundation|
|Content control:||Air Pilots|
Although a visual approach is the first type of approach normally taught to student pilots in light aircraft, this type of approach may be hazardous and careful consideration should be given before flying a visual approach in preference to an instrument approach, especially in a large aircraft. It is helpful for pilots to be very familiar with the attitudes and power settings expected in their aircraft on a normal stabilised approach so that any deviation from those expected values can help with identification of either an inappropriate approach path or an un-stabilised approach.
Flight Safety Foundation (FSF) Approach-and-landing Accident Reduction (ALAR) Briefing Note 7.4 — Visual Approach makes the following recommendation:
"Accepting an air traffic control (ATC) clearance for a visual approach or requesting a visual approach should be balanced carefully against the following:
- Darkness (light levels);
- Crew experience with airport and airport environment:
- Surrounding terrain; and/or,
- Specific airport and runway hazards (obstructions, etc.); and,
- Runway visual aids:
Make sure that if you accept a clearance for a visual approach you understand completely what responsibilities you are now accepting and what ATC expect of you.
Also be aware of what actions ATC in countries other than your home operating environment would expect from you in the event of a Missed Approach. For example in the USA a visual approach is an IFR clearance but is not an instrument approach procedure therefore it has no Missed Approach segment. (FAA AIM 5-4-23 FAA InFO 11003 Visual Approaches). You would probably be expected to remain clear of cloud until issued a further clearance by ATC. Flying the published instrument approach missed approach procedure after a visual approach can cause alarm all round and has lead in the past to close encounters with other traffic.
- If a published visual approach chart exists then it should be consulted prior to the approach being commenced.
- Any restrictions associated with visual approaches which are detailed in the Company Operations Manual must be complied with. Captains & crew members must be absolutely clear about what the visual reference requirements are during a visual approach and what action will be taken should those visual references be lost at any time.
- Prior IFR flight status should never be cancelled when accepting a visual approach.
- When contemplating a visual approach, especially in poor visibility or by night, the flight crew should make themselves aware of the terrain in the aerodrome vicinity including obstacles such as high buildings and masts.
- A stabilised approach should be flown in accordance with Company SOPs and in any case to meet the laid down or generally accepted 'gate' criteria by 500 ft above aerodrome elevation. If this is not achieved, or if the approach becomes unstable below 500 ft, a go-around should be flown.
- Navigation aids for the runway in use and the flight management system (FMS) should be used to support navigation, enhance situational awareness and to cover the possible loss of adequate visual references.
- If a visual circuit is flown prior to a visual final approach, then it should be a standard rectangular circuit based on the runway orientation. The end of the downwind leg should be determined by timing from abeam the runway landing threshold by an appropriate amount dependent on airspeed. Bank angle in turns should not exceed the lessor of thirty degrees or that required to achieve a Rate 1 turn.
- The aircraft should be configured for landing in accordance with company SOPs - typically, at least landing gear and first stage flaps will be extended before the turn onto base leg.
- minimum safe altitude should be maintained until positive visual reference and position awareness has been obtained.
The FSF Briefing Note makes the following recommendations in respect of the final stages of the approach:
- "Resist the tendency to fly a continuous closing-in turn toward the runway threshold.
- "Before turning final (depending on the distance from the runway threshold), extend landing flaps and begin reducing to the target final approach speed.
- "Estimate the glide-path angle to the runway threshold based on available visual references (e.g., VASI) or raw data (ILS glideslope or altitude/distance). [SKYbrary NOTE: If no distance information is available, it can be helpful to establish some form of gross error check on flight path by timing from a fixed reference point/ with known crossing altitude.]
- "Do not exceed a 30-degree bank angle when turning final.
- "Anticipate the crosswind effect (as applicable) to complete the turn correctly established on the extended runway centerline with the required drift correction.
- "Plan to be aligned with the runway (wings level) and stabilized at the final approach speed by 500 feet above airport elevation.
- "Monitor groundspeed variations (for wind shear awareness) and call altitudes and excessive flight-parameter deviations as for instrument approaches.
- "Maintain visual scanning toward the aiming point (typically 1,000 feet from the runway threshold) to avoid any tendency to inadvertently descend below the final approach path (use raw data or the VASI/PAPI, as available, for a cross-check)."
- Any tendency to inadvertently descend below the final approach path or to set up an inappropriately steep or shallow descent path can be reduced by ensuring descent rate is commensurate with your current Ground Speed.
- Taking note of the visual picture seen from on the glideslope during normal instrument approaches is useful in becoming familiar with assessing the progress of an approach by visual means.]
Flight Safety Foundation