PRECAUTIONARY LANDING

PRECAUTIONARY LANDING

Aim

Students must demonstrate their ability to carry out an organized procedure for landing on an unfamiliar airstrip or a landing area where the suitability of the landing surface is unknown.

Description

The Examiner will outline the reasons that require a precautionary landing. It may be a landing at an airstrip of unknown condition or some other reason dictating a landing at an airstrip other than the planned destination airport. Students must select a suitable landing area, determine the landing path, and use a planned procedure to fly an accurate approach. The approach flown must be such that a successful landing could have been accomplished in the pre-selected touchdown zone.

Performance Criteria

Private Pilot Students must:

select a suitable airstrip or other area on which a safe landing could be made;
comply with circuit procedures at an aerodrome;
make appropriate radio calls (simulated or actual);
evaluate the wind conditions, landing surface and obstructions;
select the most suitable touchdown zone;
establish the circuit at an appropriate distance from the airstrip/landing area;
correct for wind drift to maintain proper ground track;
remain oriented with the airstrip/landing area in use;
perform an effective passenger safety review;
maintain and hold circuit altitude (±100 feet) and an appropriate airspeed (±10 knots);
establish the recommended approach configuration;
maintain a stabilized approach and recommended airspeed (+10/-5 knots);
overfly the landing area in stabilized flight and maintain a safe obstacle clearance altitude (±100 feet) and a recommended airspeed (+10/-5 knots) that will permit an effective assessment of surface conditions;
indicate the type of landing to be used and perform a final approach in a manner that would permit touch down within the selected touchdown zone;
maintain crosswind correction and directional control throughout the approach and landing;
complete appropriate checks.

Note: The candidate must be able to explain the operational necessity for any variation from recommended speeds, e.g. gusty or crosswind conditions.

Commercial Pilot Students must:

conduct a precautionary landing in a timely manner before simulated or actual conditions deteriorate to an unsafe stage;
select a suitable airstrip or other area on which a safe landing could be made;
comply with circuit procedures at an aerodrome;
make appropriate radio calls (simulated or actual);
evaluate the wind conditions, landing surface and obstructions;
select the most suitable touchdown zone;
establish circuit at an appropriate distance from the airstrip/landing area;
correct for wind drift to maintain proper ground track;
remain oriented with the airstrip/landing area in use;
perform an effective passenger safety review;
maintain and hold circuit altitude (±100 feet) and an appropriate airspeed (±10 knots);
establish the recommended approach configuration;
maintain a stabilized approach and recommended airspeed (+10/-5 knots);
overfly the landing area in stabilized flight and maintain a safe obstacle clearance altitude (+100/-50 feet) and a recommended airspeed (+10/-5 knots) that will permit an effective assessment of surface conditions;
indicate the type of landing to be used and perform a final approach in a manner that would permit touch down within the selected touchdown zone;
maintain crosswind correction and directional control throughout the approach and landing;
complete appropriate checks.

Note: The candidate must be able to explain the operational necessity for any variation from recommended speeds, e.g. gusty or crosswind conditions.

Discussion

When presenting you with a scenario that outlines the reasons requiring a precautionary landing, the Examiner is quite likely to provide you with restrictive weather conditions—for example, limited visibility and low cloud ceiling (e.g., two miles and 500’ AGL). If such a scenario is established, ensure that you conform with the restrictions—if the Examiner says the ceiling is 800’ ASL, be sure that you do not go above this altitude. On other occasions, the Examiner simply asks you to land at another airport—the airstrip at Ft. Langley, for example—with the assumption that you are unsure of the condition of the strip. These two scenarios are quite different, and you want to be sure you are aware of this. The first will generally require that you select a field for landing (this is the classic form of the precautionary landing). This type, then, is for an unprepared landing area. With the second, you will be using an existing airstrip, but you are unfamiliar with it—the unfamiliar airstrip—you will have to conform with published circuit procedures and essentially join and fly a normal circuit pattern, simply combining this with the special procedures for the precautionary landings. In the case of using an unprepared landing area, you will have to define your own circuit pattern; with the unfamiliar airstrip, you will have to conform to the pre-existing circuit pattern (if it is published in the Canada Flight Supplement). In both cases you will have to inspect the approach area and the landing area from the air.

In both cases, it makes sense to begin the procedure by reducing the speed of the aircraft—this will provide more time for inspection of the ground and the flight path for obstacles. By using partial flaps, you will achieve better forward visibility, and obtain a larger buffer from stalls. So, begin by establishing the aircraft in an appropriate speed and flap configuration. Set the aircraft up for an airspeed that approximates the initial approach speed (what you fly during the base leg—in the case of the Cherokee, 80 MPH), and the initial approach flap setting (again, what you would set during the base leg—in the case of the Cherokee, 25° flaps). The most important thing to do in preparation for flying this exercise is proper trimming of the aircraft. The goal is to trim the aircraft so as to maintain stabilized level flight at the prescribed indicated airspeed, with the minimal amount of control-column inputs. It is absolutely critical that you trim with precision to maintain your airspeed and altitude. This takes time and experience, and you want to practise the manoeuvre of entering the “slow cruise” configuration (80 MPH and 25° flaps) as much as possible. Then, when it comes time to actually fly the exercise, don’t rush this part—realize that stabilized level flight is crucial for safety and crucial for doing well on the flight test. Perhaps the greatest risk is inadvertently drifting below your established altitude in conditions of poor visibility, thinking that you are in level flight when in fact you are slowly descending. The flight test requirements are specific here as well—you must keep the aircraft within 100’ of the elected or prescribed circuit altitude. It is virtually impossible to do this unless the aircraft is properly trimmed.

Once you get the aircraft established in stabilized slow cruise, take special note of your power setting used. This will become important to you when you seek to re-establish the aircraft in stabilized level flight during the low-inspection pass (perhaps the most critical phase of this exercise). Normally, 2000 RPM is a good initial power setting to establish 80 MPH with 25° flaps, but you will have to fine-tune this to adjust for your current aircraft weight. During the low-level inspection of the landing surface, the performance criteria for altitude deviation tighten up considerably—the aircraft cannot deviate more than 100’ above or 50’ below the altitude at which you elect to fly during the low-level inspection pass.

In the case of a precautionary landing at an unprepared landing area, the Examiner’s scenario will first require that you select an appropriate landing surface—a large field. Right? The field should present a smooth surface1 and be in close proximity to shelter and communication—farmhouse, etc. Apply the OWLS check: Obstructions, Wind, Length, and Surface. Be sure you give priority to selecting an appropriate field as part of your evaluation will be based on this. In the event that you are proceeding to an unfamiliar strip, you should fly a normal circuit pattern with normal altitudes, properly abiding by prescribed radio and circuit procedures for the assigned aerodrome. Ft. Langley is a favourite choice for Examiners, so be familiar with procedures there.

In the event of a precautionary landing at a field, proceed to the approach end of the field to begin the high-level inspection. Note obvious obstructions and begin the compiling of a series of ground reference points that serve to guide you around the field in conditions of restricted visibility. Begin noting these reference points at the departure end of the field. Establish a marker where you turn crosswind and where you turn downwind. If possible, follow obvious guides for the circuit legs, such as fence lines or roads. Then note where you will turn base and final, again using obvious landmarks. Be sure not to crowd, or, conversely, lose sight of the field. Importantly, during this first high-level circuit, pre-landing checks should be performed in the downwind leg.

Your next task is to perform a low-level inspection of the landing surface. This is also a practise approach. To do this, begin in the downwind leg (and this should be your second time on the downwind leg) with your pre-landing checks. Then set the aircraft up for a normal approach; as you descend to an appropriate low-level altitude for the inspection, apply power so as to maintain level flight at the same speed used in flying the first circuit—e.g., 70 knots. This is simply accomplished by committing to memory the power setting used in the circuit and resetting this for the low-level inspection. The aircraft should be positioned to the right of the centreline to provide you with a maximum viewpoint of the field. Altitude must be maintained with utmost precision, and the selected altitude must not be made below the height of surrounding obstacles—e.g., surrounding treetops or power lines—demonstrate safe decision-making in this regard. Finally, to establish the length of the field, remember that 1 second at 60 knots will cover approximately 100 ft. of ground; timing the low-level pass therefore provides a good estimation of length.

In climbing out after the inspection, adjust your flaps in accordance with the performance climb you wish to follow (i.e., obstruction or normal climb). If possible, leave your flaps alone to avoid unnecessary workload. The second circuit is standard (giving due consideration to any restrictions imposed by cloud ceilings), but this time you simply recall the landmarks previously identified and make your turns, etc., accordingly. During the downwind leg, effort must be made to communicate the landing intention to FSS:

Pilot:		“Abbotsford Radio, this is GABC on 126.7.”
FSS:		“GABC, this is Abbotsford Radio. Go ahead.”
Pilot:		“ GABC is a Piper Cherokee on a private itinerary flight from Hope to QualicumBeach. We are currently 7 NM southwest of Mission and have encountered deteriorating weather. We are putting down in a field and will contact you by telephone after landing.”
FSS:		“Roger . . . .”

Finally, passengers should be briefed on landing procedures during this downwind leg. During the exercise, the approach should be flown down to the altitude at which the inspection was flown (to repeat the low inspection procedures), and then an overshoot performed. Don’t forget to retract your flaps when you have reached a safe altitude.

Flight Safety

The greatest safety risk comes from low flying; be sure you maximize the time your eyes are checking outside the cockpit, being attentive to obstructions and traffic.
The low-level inspection leg presents special safety hazards. Do not descend below obstacles, and pay particular attention to obstacle clearance during the approach and departure portion of the circuit.
When setting up for the low-level inspection, altitude must be precisely maintained with the proper power setting.
Also in regard to the low-level inspection, be cautious of an underpowered situation in which airspeed could become dangerously slow.
Don’t forget to disengage carburettor heat if application is required on the approach.
Be conscious of the risk of bird strikes, so keep your airspeed in the lower yet safe range, and don’t try to dodge birds—they are better at manoeuvring than you.

Reference

1 See the discussions on field selection in Forced Landings.