GS Aviation Europe Ltd. Flexwing and fixed wing (3 axis) microlight training near Marlborough, Wiltshire
Winter Freeze.
With this very cold spell, and the ice and snow on the aircraft, we have been taking an hour per aircraft every morning to de-ice the wings and tail planes. Please be aware that it can take at least an hour to de-ice the aircraft on a cold morning, so make sure you get here on time or early, especially if you are the first booking of the day.The first thing to do is to remove all the loose snow/ice from the aircraft, this includes wings, tail and fuselage, please do not use the brush or broom as this will damage the wing skin and particularly the stitching. The best thing to do is use your hands preferably with gloves on!!
At this stage if the canopy cover is frozen to the aircraft skin DO NOT try to pull it off as this will damage the cover, screen and skin of the aircraft. It is best to pour warm water over the cover prior to removing.
We have the cleaning kit in the box outside the Club House, this includes a bucket for cleaning the aircraft which can be partly filled from the hot water heater in the club, then topped up with cold water so that you have a warm water mix.(Please do not run the heater for more than 2 to 3 litres as the heater element can be damaged).
This warm water can be used to run over the wings to help de-ice, be aware that if the temperature is below zero then the water could re-freeze on the wings, several buckets of water will be required to complete the wings and tail plane. Step ladders are available in the fuel store. Once this is done check all control surfaces are not iced and that the control hinges are free to move by operating the elevator, ailerons and flaps, clear any ice/snow from the hinges and velcro joints on the aileron and elevator.
PLEASE be careful when de-iceing not to damage the stitching and trilam covers, also clean the screen with the screen cleaning kit in the box, NOT the aircraft cleaning kit. The screen can be cleaned with warm water and then the blue clothes used to dry. PLEASE use vertical strokes when drying/washing the screen, ask one of the instructors for help if unsure.
If the sun is shining in the morning then pull the aircraft off its stand by pulling on the root of the prop blades. Turn the aircraft tail into sun and lower the tail gently onto the ground, get a second person to hold the tail down while you use one of the blocks by the box on the Club deck to put under the nose wheel, this allows the sun to get to work on the top surface of the wings and tail. Go and make a cup of coffee/tea while you let it do its work, this can take about an hour if the temperature is still near freezing. DO NOT use this technique if it is windy (10 knots or more) as the aircraft could potentially lift off the nose block and be damaged. IF IN DOUBT ASK AN INSTRUCTOR.
IF AT ANY TIME YOU ARE UNSURE OF ANY OF THE ASPECTS OF THE DE-ICE PROCESS, GRAB AN INSTRUCTOR OR ASK!
You have all been taught the start up process from cold, see the cold start check list:
Master on.
Fuel pump on for 5 seconds
Mags Off,
Throttle closed
Brakes ON
Full Choke
Clear prop
Turn engine over for 5 to 7 seconds
Choke Off
Mags ON
Start
The engine should fire immediatly, once fired open the throttle slightly to 2000rpm, note oil pressure is ok, and charging light has gone out. This technique works well if the ambient temperature is not below plus 5 degrees centigrade, if the engine fires and stops using the technique above, then pull full choke on and crack the throttle open about 5 to 10 mm on the lever and try again. The engine should fire and then the rpm needs to be checked, NOT ABOVE 2500rpm initially.
Rotax recommend initial rpm at 2000 for about 2 minutes, then 2500 to 2800 rpm to warm up to about 50 degrees oil temperature prior to mag checks at 3000 rpm, this can take 7 to 8 minutes in the winter, PLEASE BE PATIENT. Be aware that the 912 series engines do run rough initially, this is due to a combination of carb ice and the engine being cold. The moisture content in the air and the lack of warm air under the engine cowls will allow ice to form in the carburettors, if the engine starts to run rough and rpm drops below 2500 then increase rpm to back up 2500, you may find that if the ice breaks away into the engine the revs will increase again above 2500, if this happens reset 2500 with a maximum of 2800 rpm.
Please DO NOT sit and wind the engine over and flatten the battery, stop and grab a member of staff.
You will have been taught this start up process with us, if you are unsure ASK.
We are looking into fitting wing covers for the winter on all aircraft, in the hope that this shortens the de-iceing process.