Monday, June 13, 2011

The Precautionary Landing Procedure

When bush plane conditions of a landing areaare unknown simply because the landing is an unplanned one or if no advance data is available, you needs to perform a precautionary landing.


This happens ifyou are flying to such a location on as part of a planned flight, or because an unplanned landing is a good idea as a result of changes in the weather, low fuel or oil pressure, or perhaps because of a bush planemedical emergency.


For a backcountry strip, or even a non-dedicated strip like a farmers field, a moose meadow or a gravel bar a fly over inspection is needed, and typically the only method to obtain the requisite details to land.


Unplanned landings as a result of urgent, but non-emergency situations require the same sort of approach. Fuel guages that read empty, even when you're sure that the tanks are still full, require that you land in order to investigate. In most cases you can't determine whether the gagge is faulty or the tank is leaking from your seat in the cockpit. Still, if you have sufficient power and the airplane is behaving normally you can't consider it an emergency. The engine hasn't failed, there isn't a massive loss of power, and there is no imminenet danger to life or machine. The landing is unplanned, but it is a precaution. This is also the case for medical issues, minor mechanical problems or bush planelow oil pressure.


Another reason for precautionary landings is deterioration of weather. You may begin a flight in acceptable weather conditions only to have them deteriorate pst acceptable VFR standards. Low fuel or bad weather behind you may prevent you from simply turning around or diverting. In this a precautionary landing may be in order.


Use the following Precautionary Landing procedure if any of the following things occur:

Fuel is low, or the gauges read low, or oil pressure has dropped;

There is a medical emergency that is best dealt with on the ground;

If weather has deteriorated below VFR minima;

The bush plane conditions at the landing area are unknown;


The first three scenarios are Pan Pan, not Mayday, situations. There is no need to make the Pan Pan call if you are making a planned landing at an unknown airstrip. Forced landings are for when you lose an engine entirely or suffer a massive loss of power; precautionary landings are executed when you are not in imminent danger - don't get them confused.



This procedure has 8 steps:



One) Begin at the regular circuit height of 1000 feet AGL

Two) Fly a normal downwing leg to inspect the landing zone to decide if a lower pass is safe; this is called the high inspection. Keep an eye out for any hazards like trees, towers, power poles or anything else tha may effect closer inspection. Scan for cues to wind velocity and direction.



Three) The next stage is low inspection, which is an upwind leg flown at a lower altitude. Fly parallel to the landing area in order to examine it. Establish the airplane in trimmed, level flight at 60 knots with flaps at 10 degrees. Fly as low as you safely can while scanning the proposed landing strip. Try to detect anything, whether obstacles or terrain conditions that will effect your landing. At a speed of 60 knots you cover 100 feet every second, so it's a good way to estimate landing strip length. Thirteen to fourteen seconds should give you enough room to land, depending on conditions.



Four) Overshoot, apply full power and return to circuit altitude. Get back into a normal circuit pattern in anticipation of landing.

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Five) Make your radio call advising who you are, whereyou are and what you're doing



Six) Brief any passengers;



Seven) Complete the normal pre-landing checks - primer in and locked, master on, mags both, cicuit breakers/fuses, carb heat hot, mixture full rich, seats and harnesses secure, fuel on, test brakes;.



(These last three are sometimes called the 3 Ps, Pan Pan, passenger briefing and pre-landing )



Eight) Land the airplane as appropriate. Whether it is a short field, soft field or combination of the two will be dependent on the conditions. Don't forget to take any obstacles that can't be avoided into account

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