What are the characteristics and precautions of flying in winter?
The weather that affects flying in winter is mainly low clouds, low visibility, low temperatures, strong winds, ice and snow. They have a great impact on flight safety. How to take favorable measures to ensure flight safety when flying in this kind of weather is an issue that we should pay great attention to.
1. Flying in low cloud and low visibility weather
(1) The impact of low cloud and low visibility on flight
The weather phenomena that affect visibility mainly include smoke , fog, wind and sand, blowing snow, low clouds and precipitation, but the most common ones that have the greatest impact on approach and landing are heavy fog and low clouds. Especially when the visibility is about 1 kilometer and the weather conditions are close to the edge, it is difficult for the crew to see the runway clearly, which brings many difficulties to takeoff, approach and landing. If the pilot controls improperly and the crew does not cooperate well, it will seriously affect flight safety. threaten.
(2) Precautions when flying in low clouds and low visibility:
1. Appropriately increase the amount of backup fuel before taking off to leave sufficient room for alternate landing.
2. Pre-select a suitable backup site. If necessary, multiple alternate landing sites can be made and alternate landing routes prepared in advance.
3. Prepare the approach briefing carefully, clarify the division of labor among the crew, strengthen the awareness of go-around and alternate landing, be familiar with the go-around maneuver, and make all preparations for the approach.
4. Establish landing configuration as early as possible, establish a stable instrument approach, and reduce energy distraction.
5. Optimize unit resource management and reasonably allocate resources.
When the aircraft enters final approach, the captain hands over the control to the co-pilot. The co-pilot controls the aircraft strictly according to the instruments and maintains control; the captain monitors the work of the co-pilot and various equipment; Other crew members monitor the status of the aircraft. If an abnormality occurs during the approach or the decision altitude is reached, and neither the captain nor the first officer takes corresponding measures, they should shout out the status change of the aircraft or "below the decision altitude" to alert the aircraft. The commander and co-pilot should take measures and loudly remind "go around" when safe landing conditions are not met.
2. Flying in low temperature and strong winds
(1) The impact of low temperature and strong winds on flying
In winter, whenever cold air passes through, low temperatures and strong winds often occur Along with this, especially in North China, strong winds are often mixed with turbulence, which has a considerable impact on takeoff and landing. The specific manifestations are as follows:
1. Flying with strong headwinds and crosswinds can easily cause the aircraft to be visually low, land heavily, and deviate from the runway;
2. When flying at low temperatures, it is easy to cause Runs, leaks, etc. will cause greater harm to the oil and gas system;
(2) Precautions when flying in low temperatures and strong winds:
1. Strictly master headwind and crosswind standards, especially When there is ice or snow on the runway, strictly follow the principle of halving the crosswind standard (dry runway), pay attention to crosswind takeoff and landing operations, and prevent deviation from the runway;
2. When flying in low temperatures and strong winds, You will clearly feel that the speed disappears quickly during the leveling process. If you do not pay attention to this feature, it may easily cause a low visual inspection or a heavy landing. Due to the influence of gusts during the approach, the airspeed indicator indication will be unstable, swing and have false speed, so the approach target speed should be corrected according to regulations, and it is better to be slightly higher than lower during the maintenance process. The throttle can be closed appropriately late or slowly. If it is about to level off, the method of landing with the throttle to level off may be used to correct the situation.
3. If strong winds are accompanied by wind shear, follow the principle of "avoidance, prevention and recovery" as appropriate. Wind shear will affect the stability and maneuverability of the aircraft, affecting certain aircraft. The accuracy of these instruments and changes in the aircraft's trajectory should arouse our vigilance!
4. Start in strong tailwind should be avoided to avoid over-temperature or surge at engine start.
5. Due to the low temperature, pay attention to check whether there are leaks in the fuel, lubricating oil, hydraulic oil tanks and pipelines before flying in winter. Check whether the height of the shock absorber pillar is within the specified range, whether there is leakage in the shock absorber pillar, and whether the tire pressure meets the standards.
3. Flying in Ice and Snow Weather
Snowfall and ice accumulation are the biggest threats to safe flight in various weather conditions in winter.
(1) The impact of ice accumulation on aircraft on flight:
1. Ice accumulation on the engine reduces the thrust, and it is easy to suck the fallen ice into the engine and damage the compressor blades. Cause engine failure;
2. Ice accumulation on the wings reduces the lift of the aircraft and increases the drag. Tests have shown that 2-3 mm of frost will increase the stall speed by 35% and double the takeoff distance. During takeoff, the airflow will separate prematurely and significantly from the wings. When the aircraft starts flying at a higher angle of attack, the lift coefficient of the icing aircraft is 15%-20% smaller than that of a normal aircraft, which may cause the runway to be not long enough and overrun the runway. On November 28, 2004, a Bombardier Challenger aircraft crashed due to ice accumulation on its wings near Montrose, Colorado, USA.
3. Ice accumulates on the pitot tube, blocking the dynamic and static pressure holes, which will increase the error of the altimeter, airspeed indicator, and elevation speed indicator or even cause them to malfunction.
4. Ice accumulation in the fuel tank vent will cause difficulty in supplying fuel to the engine. If ice accumulates on the exhaust valve, it will affect the normal operation of the air conditioning and boosting system.
Therefore, we should strengthen our awareness of ice removal and anti-icing and fly without ice, snow or frost.
(2) Precautions when flying in ice and snow:
1. The external inspection of the aircraft in ice and snow weather must be particularly careful. Check the surface of the aircraft, especially whether there is ice, snow, and frost on each flight control surface, and whether each control surface is flexible. There should be no ice or snow near each pitot tube and static pressure hole.
2. If you need to use ground de-icing fluid for de-icing, you must master the de-icing time according to the anti-icing time of different anti-icing fluids to prevent re-icing due to too long waiting time after using de-icing. ice.
3. After starting, the engine should run at idle for two minutes before changing the thrust, so that the oil temperature can rise and the engine can be well lubricated. . When the aircraft is taxiing, thrust should be used gently. When taxiing on icy and snowy roads, the speed should be lower than the normal taxiing speed. Use the front wheels to turn and brake gently to avoid sideslip.
4. When taxiing in ice and snow, you should brake appropriately to prevent the brake disc from freezing and endangering safety.
5. Before taking off, the crew should check again that all control surfaces are working properly before taking off.
6. Use the anti-icing or de-icing system correctly during flight. When flying at high altitudes with severe icing, it is recommended not to use autopilot to control the aircraft for a long time to prevent the flight control surface from freezing due to ice and endangering flight safety.
7. When the aircraft lands on an ice or snow runway, it should strive to touch down near the center line of the runway, eliminate sideways as soon as possible, and maintain a good taxiing direction. Be careful when exiting the runway and avoid turning with excess speed to prevent the aircraft from losing control.
8. If you spend the night in a cold airport, block the wheels and release the parking brake to prevent the brake pads from freezing to death.
The above is a relevant discussion and is for reference only. I hope it will be helpful to you