Cold WX Operations Flashcards
Cold Wx operation considerations are concerned with?
low temps, ice, snow, slush, standing water on airplane, ramps, taxiways, RW’s.
Explain Icing conditions
OAT on ground, or TAT in flights is 10deg or below and:
*visible moisture (clouds, fog with viz less than 1600m, rain, snow, sleet, ice crystals, present or
*ice, snow , slush, standing water on ramps, taxiways, runways.
Name the MAIN procedures which are part of the Cold WX OPS Suppl proc
Exterior inspection
Preflight FO
Engine Start
EAI operation ground
WAI ground
Before Taxi
De/Anti Icing
Before Take Off
Takeoff
EAI in flight
Fan ice removal
WAI in flight
COLD TEMP Correction
App and landing
After Landing
Shutdown
Secure
Do normal exterior inspection, with additional steps?
Surfaces
*light coatings of frost up to 3mm lower wing due cold fuel is OK, as long as LED, control surface, tab surface, upper wind surface, winglet surface, control balance panel cavities must be free of snow, ice, frost. Thin HOAR frost upper surface OK, if all vents and ports clear.This hoarfrost is a uniform white deposit of fine crystalline texture, on exposed surfaces on cold and cloudless night. Thin enough to distinguish surface features underneath.
Control surface balance panel cavities
check drainage after snow removal, puddles water may freeze inflight.
pitot probes and ports
all free of snow, ice.Water rundown after snow removal may free immediately forward of static ports and cause ice buildup which disturbs airflow over static ports.
Air conditioning inlet and exits
air inlets, exists, outflow valve, free snow and ice.APU operating, verify outflow valve fully open.
Engine inlets
inlet cowling free snow, ice
fab free to rotate
Snow, ice on fan spinner or fan blade during extended shutdown periods, must be removed by maintenance or other means before engine start.
Snow/Ice on fan spinner/fan blades during approach or taxi in is OK, if fan free to rotate and snow/ice removed using ice shedding proc during taxi out and before setting TO thrust.
Fuel tank vents
landing gear doors
APU air inlets.
free of snow, ice before APU start.
Preflight proc FO?
Probe Heat switches ON
Engine cold soaked for 1 or + hours temps below -40deg?
dont start or motor engine.Maintenance heating of Hydro Mechanical Unit.
Engine cold soaked for 3 or + hours temps below -40deg?
dont start or motor engine.Maintenance procedures for adverse weather starter servicing.
Temps below -35deg?
idle for 2min, before changing thrust lever position.
Oil pressure scenario?
several min for OIL PRESSURE to reach normal operating pressure. Oil P may go above normal range, and OIL FILTER BYPASS may illuminate. Operate engine IDLE until oil press normal range. OIL press remains above normal, after OIL TEMP is stable, shut down engine.
Display Units during engine start cold wx?
additional WU time before displayed engine indictions accurately show changing values. May appear less bright than normal.
Engine ani ice after start?
selected on after both engines started. Remain ON during all ground ops if icing conditions exist or anticipated.
Use which criteria to use EAI?
Temp and visible moisture. DOnt use airframe visual cues. Late activation allow excessive ingestion of ice result damage of failure.
Light indication using EAI?
COWL VALVE OPEN light bright, then DIM. COWL ANTI ICE light stays extinguished.
COWL VALVE OPEN light stays BRIGHT with engines IDLE?
*APU BLEED OFF
*ISOLATION VALVE AUTO
*Area behind clear
*Thrust increase Max 30% N1
WAI, when to use and not to use?
After engine start and TO with icing conditions, unless AC protected by Type 11 or IV fluid.
WAI use, which lights ON?
L/R VALVE OPEN light Bright, then dim.
VALVE OPEN lights cycle bright/dim?
Due to control valves cycling closed/open in response to thrust setting and duct temp.
IDG and COLD OIL?
IDG normally stabilize 1min, can take 5min to produce steady power due cold oil.
Flight control check @ low temps?
increase in control forces
Setting flaps, if they STOP?
Flap lever should be placed immediately in same position as indicated.
Taxi Method out?
Reduced speed, smaller nose wheel and rudder inputs.Differential thrust to keep turn momentum. SLippery tways high speed or with high crosswinds = SKID!
Operate engines over standing de/anti-ice fluid -
use minimum thrust. Build up of fluid on engine compressor = compressor stalls and engine surges.
EAI required and OAT 3 of below?
Engine run up to minimize build up.
Min 70% N1 30s at intervals maximum 30min.
Fan blade ice build is cumulative?
Fan spinner and blades not deiced prior taxi out, time engines were operating during taxi IN should be included in the 30min interval.
Airport surface condition dont allow 70% N1?
Set thrust level high as practical
Freezing rain, freezing drizzle, freezing fog or heavy snow?
Run Ups 70% N1 for 1sec duration, max interval 10min.
De/anti-ice rotation rate?
Normal. Residual fluid causes tempo decrease in lift and increase in drag.
APU during DA-Icing?
ONly if needed.
DA ice complete, engine bleed?
Wait 1 min
TO static engine run up?
OAT 3 deg or below, 70% N1 minimum, 30s highly “recommended”. Confirm stable engine operation before start of TO roll.
EAI in flight?
ON when icing conditions exist or anticipated except:
*climb and cruise Below -40deg C SAT
EAI must be ON before, during descent all icing conditions, including below -40deg C. DONT USE EAI when TAT above 10deg.
Prolonged ops in moderate to severe icing conditions?
Lead to fan blade/spinner icing and engine vibration.
Avoid Severed Icing?
Change in ALT and/or SPEED
When to do FAN Ice removal?
FLight MOD to SEV icing cannot be avoided.
FAN ICE REMOVAL?
*ENG START SWITCHES FLT
*A/T disengage
*THRUST INCREASE
Min 80% N1 for 1sec
*Thrust reduce
WAIT 15sec - eng vibration level to stabilize.
Vib less than 4.0 units after thrust reduced, repeat every 15min or sooner.
A/T engage.
ENG VIB 4.0 or greater after thrust reduced, do ENG HIGH VIB NNC.
When to use WAI?
ice on FD window frames, windshield center post, windshield wiper.
Primary method to use WAI?
De-icer, but can be used as De or Anti icer. DEicer method cleanest airfoil., least possible runback ice formation and least thrust and fuel penalty.
Secondary WAI method?
anti ice, before accumulation. Do this only during extended operations in MOD or Severe icing conditions, like holding.
WAI ABOVE FL350?
BLEED TRIP AND POSSIBLE LOSS OF CABIN PRESS.
Prolonged ops in icing conditions?
LEF and TEF extended not recommended. Holding with flaps extended PROHIBITED.
Why COLD temp Alt corrections?
Low temps = altimeter errors = t= reduced terrain clearance.
Temp colder than ISA?
True Altitude lower than indicated alt
Altimeter errors very large when?
*-30deg C or colder
*Increasing height above altimeter reference source
Apply corrections for?
*Minimum Departure
*en route
*app alt
*Missed App alt
Advice atc of above
*MDA/DA
Explain The altitude correction method. Just check the FZ procedure as well 10%/20%
Alt flow minus elevation = height above altimeter reference setting. Enter the table with AIRPORT TEMP and HEIGHT ABOVE ALTIMETER REFERENCE SOURCE. Read the intersect. Add correction to the published minimum alt. 100 increments. MCP round to highest 100.
Alt Correction NOT NEEDED?
ATC Vectors
ATC assigned flight level
Reported airport Temp above 0C or if airport temp at above min published temp for the procedure flown.
After landing icing conditions:
Prolonged ops icing = flaps extended = or when airframe ice observed = or if RW/TWAY contaminated with ice, snow, slush, standing water= Retract flaps 15 until area have been checked to be free of contaminants.
EAI after landing Icing conditions?
KEEP ON
Shutdown icing conditions, trim? Why?
Set 5 units. Prevents melting snow, ice from running into tail cone. Excessive water in tail cone can freeze and lock controls.
Secure Proc?
Attended and need warm air circulation.
Unattended, or staying overnight
Cold WX maintenance proc for securing AC
covers/plugs
water storage drained
toilets drained
doors windows closed
battery removed - 18C deg.
