NATOPS Ch14 Extreme Wx Ops Flashcards
When should the aircraft be hangared?
If hangar space is available, aircraft SHOULD be kept in a heated hangar when OAT is forecast below 0°C (32°F)
What is the approved method to remove ice?
SHALL never be done by scraping or chipping
Remove ice by applying heat or approved deice fluids
Why may the PCL Hard to move in cold weather?
May be indicative of frozen PAS or PAS cable
Do not force PCL movement as this may damage the PAS cable
How will oil be affected during Starts in Extreme Cold (-40°C)
Oil pressure may remain at 0 for about the first 20-30 seconds after initiating the start. Abort start if there is no oil pressure within 1 min after initiating a start
Once oil pressure begins to rise it will rise to the 100psi limit quickly, as temperature increases pressure will decrease. Do not advance PCL to FLY until oil pressure is indicating normal.
Describe the Oil Bypass
Indicator has thermal lockout below 38°C preventing PDI from popping OIL FILTER BYPASS may appear during cold starts–disappears above 38°C
What are some considerations when executing an Engine Start after a Cold Overnight?
Watch for rise in TGT within 40 sec. If no TGT rise is evident, prime the engine and attempt another start
If there is no overboard fuel flow, inspect for ice in the sumps and filters
Engine starts on an Icy Surface
Recommended to use no-rotor brake start procedures to avoid rotation from rapid increase in torque
Warmup and Control Exercise for starts below -17°C
-17°C to -31°C
Warm up engine at idle for 3 min; during warmup position cyclic control 1in forward of neutral and move tail rotor pedals alternately 3/8in
-31°C to -40°C
Same, but position cyclic 5/8in forward, gradually moving to 3in forward; move each tail pedal 1/8in gradually moving to 1/2in
How do you Taxi in Cold weather?
SHOULD NOT be accomplished until all engine and system pressures are within normal limits
Slow speeds, wide radius turns, Do not exceed 15kgs
How long to power up the MD/FDs in Cold?
When powering up MD/FDs in temps of 0°C or colder, the displays will illuminate within 15 seconds but up to 15 minutes may be required before full performance is available
How long before full use of the Transducer in Cold?
What is indicative of a battery failure?
For in-air temps >5°C, normal charging time before unfolding or transmitting is approx 10 min after mission power applied (ST/R powered on); in-air temps of <5°C may take up to 45 min before successful array unfolding or transmissions
If battery doesn’t reach at least 60% within 1 hr of applying power for temps above 5°C or 1 1/2 hrs for temps less than 5°C battery may be unable to support normal ops
The inability of battery to consistently reach a charge of 60% may indicate a battery failure (typical codes include 1111 or 1174 and DOME PING ABORTED) TIME TO PING not decreasing indicates failure to charge (execute procedure); if doesn’t fix charge, battery pack may have failed and dipping ops must be suspended
What are some precautions for ops in snow?
Horizon/loose snow/visible moisture
May have no visual horizon over large expanses of snow
Avoid loose, powdery snow to minimize visibility restrictions
Takeoffs into fog or low clouds when temp is at or near freezing could result in engine air inlet icing–climb speeds should be higher than normal under such conditions
How do you execute Snow Landings?
Running landings are recommended on loose snow
Maintain enough airspeed to remain ahead of snow cloud but not be over approx 15 knots at touchdown
Be ready to takeoff immediately if a wheel should hang up or break through crust–do not reduce power until it is positively determined the aircraft will not settle
When shutting down on icy surface, advisable to let the rotor coast down to avoid possible aircraft rotation by a rapid application of rotor brake
How much torque does ECS Hot use? How much gas will you lose?
ECS - HOT
Max torque available may be reduced by approx 5% per engine
Fuel flow will increase approx 45lbs per hour per engine
What should you do before leaving aircraft if its going to be cold?
- Protect wheels from freezing to ground by towing/taxiing onto planks or sandbags
- Leave parking brake off–chock and chain
- Open scuppers on cockpit windows
- Drain moisture accumulation from sumps and strainers
- Install engine inlet plugs after shutdown to prevent accumulation of ice and snow in engines
When is flight into icing permitted?
What are some considerations with ice shedding?
Into known icing without deice equipment is prohibited
Into forecasted or known moderate or severe icing is prohibited
(Flight into known trace/light icing okay with functioning Anti-Ice/De-ice)
Shedding from rotors and components presents a hazard to personnel during landing and shutdown
Shedding from main rotor may strike tail rotor during rapid descents following flight in icing conditions
What happens if pooled water freezes on the aircraft?
Water pooled in intake ducting will freeze and may result in FOD–must be removed prior to freezing
Intakes SHALL also be checked for ice on preflight
When is Anti-ice and Deice Pitot Heat required?
Anti-Ice SHALL be turned on when OAT reaches 5°C or below in visible moisture
Pitot Heat SHALL be turned on when OAT reaches 5°C or below or when visible moisture is present
Where will we notice Initial Ice Accumulation?
Will be noted on windshield wiper arms, mirror support brackets, main landing gear and external stores
How does the Ice Rate Detector work?
No2 engine cowling activates ICE DETECTED and turns on aspirate heater to shed the ice Ice melts and caution disappears
Frequency at which ICE DETECTED cycles on and off may give indication of icing severity
How much will torque increase? How much increase is acceptable?
Additional torque increase up to 14% per engine may be experienced due to ice buildup during normal operations of blade deice system
WARNING
Ice accumulation resulting in a 20% increase in torque indicates normal autorotational rotor rpm may not be attainable should a dual engine failure occur
Increase over 10% matched torque should result in urgent consideration to vacate the environment unless task is considered essential
If torque increases 20% above that required for level flight at the airspeed being maintained prior to entering icing, exit the icing environment or land the aircraft as soon as possible
What are the results of Asymmetric Shedding?
If blade deice is not operating, asymmetric shedding may cause imbalances which may result in severe vibrations
These should subside after 30-60sec – some impact damage can be expected during flight into icing
What is a risk during Blade Fold after flight in icing?
Potential exists for incomplete blade fold following flight in icing
Visually ensure all blade fold microswitch contact surfaces are free of accumulation prior to attempting blade fold sequence
What are some risks of a Lightning Strike?
A severe lightning strike to the aircraft is likely to result in the loss of all electrical power sources except the battery (including APU generator even if it not operating at the time) and damage a majority of electronic circuits
Due to electrical system design, battery power may only be available for the components on the battery utility bus (only backup instruments available)
Lightning strike that induces voltages in the engines may damage DECU and and possibly other related components
How do you fly in turbulence?
Moderate - limit airspeed to blade stall speed minus 15 knots
Light - limit airspeed to blade stall speed minus 10 knots
Set and leave collective setting using AI as primary pitch instrument
Pitot static may vary as much as 40 KIAS by maintaining a fixed collective position and level flight, airspeed will remain relatively constant
How do you start or stop the Rotors in High Wind?
Hold cyclic into the wind and increase RPM immediately to prevent excessive flapping
Hold cyclic into wind to reduce bumping against droop stops–apply rotor brake when rotor speed is below 40%
What could happen if you have Nose Bay Water Intrusion?
May cause AFCC failure
What are some effects of opperating in Hot Weather?
Requires more power
Fuel densities will decrease as ambient temp rises, resulting in decrease in operating range
High humidity increases DA and effectively reduces efficiency of rotor system. For every 10% increase in relative humidity, the DA increases approx 100ft
What if Oil Pressure is low while in Hot Weather?
If engine oil pressure falls into red range or ENGINE OIL PRESS caution appears when PCL is in IDLE, slightly advance PCL. If oil pressure returns to yellow range and caution disappears, engine oil pressure is acceptable
What are some considertions when operating in a Dusty environment?
Consider towing for takeoff because sand and dust may cause severe damage
May cause ICE DETECTED caution
Check for sand and dust in control hinges, actuating linkages and inspect tires for proper inflation (high temp may over-inflate)
Check oleo struts, especially near cylinder seal and remove accumulation with clean, dry rag
How do you take off or land in a Dusty environment?
Get airborne as quickly as possible (especially if taxiing) to limit ingested dust and sand and minimize erosion of rotor blades
Execute steep to no hover landing
