Which of the following statements is true regarding moderate to severe airframe icing ?
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Which of the following statements is true regarding moderate to severe airframe icing ?
Which of the following conditions is most likely to cause airframe icing ?
Rime ice forms through freezing onto aircraft surfaces of Small supercooled water drops. clear ice forms on an aircraft the freezing of large supercooled water drops rime ice forms through freezing onto aircraft surfaces of small supercooled water drops. 
How does a pilot react to heavy freezing rain at 2000 ft/agl when he unable to deice nor land He turns back before aircraft loses manoeuvrability. freezing rain associated with warm fronts warm occlusions in a warm front freezing level lower than behind (in warm sector) the slope means that freezing rain will be falling on anything underneath at 2000 ft above ground level descending could be dangerous you are not sure to reach enough warmer air to deice remain at same altitude will give a dangerous build up of ice on airframe ascend into cold air means you will not lose ice climbing into frontal cloud will give more ice the best solution to turn back to get out of this freezing rain quickly. 
In which of following conditions moderate to severe airframe icing most likely to be encountered In nimbostratus cloud. airframe icing will not happen in cirrus cloud (composed of ice crystals) or if temperature above 0ºc ns (nimbostratus) produces heavy rain if rain falls through a cold air mass (below freezing level) moderate to severe airframe icing can occur in clear air you can only have light icing. 
What flying conditions are normally encountered when flying in cirrus clouds Average horizontal visibility more than m nil icing. airframe icing will not happen in cirrus cloud (composed of ice crystals) or if temperature above 0ºc ns (nimbostratus) produces heavy rain if rain falls through a cold air mass (below freezing level) moderate to severe airframe icing can occur in clear air you can only have light icing. Question 145-8
How does freezing rain develop Rain falls through a layer where temperatures are below °c. freezing rain encountered ahead of a warm front in winter in summer (and sometimes behind a cold front). Question 145-9
What weather conditions in region of alps would you expect with foehn from south Clouds on southern sides of passes in alps. the southerly wind will give a foehn 'from south' clouds on southern side. Question 145-10
Under which conditions would you expect heaviest clear ice accretion to occur in a cb Between 2°c 5°c. arizona there another question that states that as water droplets are bigger in cumulus clouds clear ice would appear between 0 to 23 degrees so why isnt answer 'between 20 30' correct? the question you are talking about is 'ice accretion to airframe likely to be most hazardous at temperatures between 0°c 23°c in large cu' explanation this question the most severe icing clear ice clear ice will form in stratus between 0ºc 7ºc but in cumulus larger droplet size will give clear ice at temperature between 0ºc ?23ºc since clear ice accretion can occur at temperatures warmer than 20°c answer between 2°c 15°c the most correct one. Question 145-11
Clear ice forms on an aircraft the freezing of Large supercooled water drops. clear ice forms on an aircraft the freezing of large supercooled water drops rime ice forms through freezing onto aircraft surfaces of small supercooled water drops. Question 145-12
What weather conditions would you expect at a squall line Large supercooled water drops. when many individual thunderstorms organize into a nearly continuous line a squall line born they can be more than 80 nm long often form 40 to 130 nm ahead of advancing cold fronts racing along squall line thunderstorms blast ground with torrents of rain hail driven winds gusting higher than 50 kt. Question 145-13
What the approximate maximum diameter of a area affected damaging winds at surface caused a microburst Large supercooled water drops. a microburst/downburst a localized area of damaging winds caused air rapidly flowing down out of a thunderstorm a microburst occurs when cold air high in a thunderstorm descends accelerates as stream of cold air reaches ground it spreads out can accelerate even further. Question 145-14
In general visibility during rainfall compared to during drizzle Large supercooled water drops. the two forms of liquid precipitation drizzle rain are classified in a number of ways depending on size of drops visibility associated with precipitation the rate at which it falls drizzle which defined as drops with diameters less than 0 02 inches falling close together usually falls from stratus clouds the relatively thin stratus clouds have slow upward moving air currents in these conditions cloud droplets have little time to grow before they become too heavy the air currents to support the drops fall to ground appearing to float in air currents as seen in graphic above intensity of drizzle based on visibility at time precipitation falling rain which composed of widely separated drops with diameters usually greater than 0 02 inches generally falls from towering cumulus clouds the cumulus clouds with fast upward moving air currents allow cloud droplets to combine grow raindrops can reach sizes up to 0 25 inches before falling to ground the intensity of rain based on amount that falls in one hour the intensity can also be estimated visually. Question 145-15
Which of following symbols represents a squall line 264 Large supercooled water drops. icao annex 3 meteorological service international air navigation . Question 145-16
Over madrid what intensity of turbulence and icing forecast at fl 200 267 Moderate turbulence moderate icing. icao annex 3 meteorological service international air navigation bkn ovc lyr broken overcast layer moderate icing from fl100 to fl210 moderate turbulence from fl100 to fl210. Question 145-17
You are flying from munich to amsterdam which of following flight levels would you choose in order to avoid turbulence and icing 272 Moderate turbulence moderate icing. there icing from below fl100 (xxx) up to fl180 turbulence up to fl200 cat between fl280 fl390 you must choose a flight level from fl210 to fl270. Question 145-18
In what height range and at what intensity could you encounter turbulence in cat area n°2 273 From fl 22 to fl 4 moderate. . Question 145-19
At which position the development of thunderstorms most likely and what the maximum height of cb clouds at 00 utc 275 From fl 22 to fl 4 moderate. at position b you can read in weather bubble with lightening arrow isol embd cb from below chart level up to fl 270 isolated embedded cumulonimbus means probably thunderstorms the maximum height of cb clouds forecast up to fl270. Question 145-20
Flight lisbon to bordeaux eta 1800 utc at eta bordeaux what the lowest quoted visibility forecast taf lfbd 281400z 281524 26015kt 9999 shra bkn020 tempo 1620 26020g30kt 8000 +shra bkn015cb prob30 tsra = From fl 22 to fl 4 moderate. at position b you can read in weather bubble with lightening arrow isol embd cb from below chart level up to fl 270 isolated embedded cumulonimbus means probably thunderstorms the maximum height of cb clouds forecast up to fl270. Question 145-21
The lowest visibility forecast at eta zurich 1430 utc lszh 261019 20018g30kt 9999 ra sct050 bkn080 tempo 23012kt 6000 dz bkn015 bkn030 becmg 1518 23020g35kt 4000 ra ovc010= From fl 22 to fl 4 moderate. the lowest visibility forecast will generally be more than 10 km but it could go down to 6 km temporarily between 1000z to 1900z lszh 261019 20018g30kt 9999 ra sct050 bkn080 tempo 23012kt 6000 dz bkn015 bkn030 becmg 1518 23020g35kt 4000 ra ovc010= after 1500z visibility will reduce to 4000 m. Question 145-22
A microburst phenomenon can arise in Downdraught of a cumulonimbus at mature stage. a microburst/downburst a localized area of damaging winds caused air rapidly flowing down out of a thunderstorm a microburst occurs when cold air high in a thunderstorm descends accelerates (the mature stage ) as stream of cold air reaches ground it spreads out can accelerate even further. Question 145-23
All pilots encountering clear air turbulence are requested to report it you experience cat which causes passengers and crew to feel definite strain against their seat belt or shoulders straps unsecured objects are dislodged food service and walking are difficult this should be reported as Downdraught of a cumulonimbus at mature stage. a microburst/downburst a localized area of damaging winds caused air rapidly flowing down out of a thunderstorm a microburst occurs when cold air high in a thunderstorm descends accelerates (the mature stage ) as stream of cold air reaches ground it spreads out can accelerate even further. Question 145-24
In weather briefing room during pre flight phase of a passenger flight from zurich to rome you examine following weather reports of pressing importance at time einn shannon 2808 sigmet 2 valid 0800/1100 loc sev turb fcst einn fir blw fl 050 south of 53n wkn =limm milano 2809 sigmet 2 valid 0900/1500 mod sev cat btn fl 250 and fl 430 fcst limm fir stnr nc =egll london 2808 sigmet nr01 valid 0800/1200 london xfir isol cb embd in lyr cloud fcst tops fl 300 btn 52n and 54n east of 002e sev ice sev turb ts also fcst mov e wkn =which decision correct Because of expected turbulence you select a flight level below fl 25. information regarding london shannon are irrelevant in this case since milano lies more or less on route zurich rome we are only interested in information included in sigmet milano which clearly states that moderate to severe clear air turbulence present from fl250 to fl430 hence flight below fl250 would be desirable. Question 145-25
Isolated thunderstorms of a local nature are generally caused Because of expected turbulence you select a flight level below fl 25. thermal triggering depends on relatively light winds that allow high surface temperature to develop during summer you can expect local isolated thunderstorms arising from thermal triggering mostly in mid afternoon. Question 145-26
A zone of strong convection currents encountered during a flight in spite of moderate gust you decide to continue flight what are your precautionary measures Decrease speed / try to climb above zone of convective currents if aircraft performance parameters allow. by decreasing speed you will reduce risk to encounter some buffeting (with gusts airflow speed on wing may locally reach mach 1). Question 145-27
How long does a typical microburst last Decrease speed / try to climb above zone of convective currents if aircraft performance parameters allow. a microburst/downburst a localized area of damaging winds caused air rapidly flowing down out of a thunderstorm a microburst occurs when cold air high in a thunderstorm descends accelerates (the mature stage) as stream of cold air reaches ground it spreads out can accelerate even further. Question 145-28
What normally most effective measure to reduce or avoid cat effects Change of flight level. a microburst/downburst a localized area of damaging winds caused air rapidly flowing down out of a thunderstorm a microburst occurs when cold air high in a thunderstorm descends accelerates (the mature stage) as stream of cold air reaches ground it spreads out can accelerate even further. Question 145-29
On approach surface temperature given as 5°c the freezing level at 3000 ft/agl at 4000 ft/agl there a solid cloud layer from which rain falling according to weather briefing clouds are due to an inversion caused warm air sliding up and over an inclined front would you expect icing Yes between ground level 3 ft/agl. a microburst/downburst a localized area of damaging winds caused air rapidly flowing down out of a thunderstorm a microburst occurs when cold air high in a thunderstorm descends accelerates (the mature stage) as stream of cold air reaches ground it spreads out can accelerate even further. Question 145-30
Which of following conditions are most favourable to formation of mountain waves Stable air at mountain top altitude a wind at least 2 knots blowing across mountain ridge. standing waves = orographic waves = mountain waves in addition to a stable layer of air over a substantial mountain range conditions most favourable to development of standing waves are wind speed excess of 20 kt at surface increasing with height wind direction perpendicular to general direction of range. Question 145-31
An aircraft approaching a cold front from warm air mass side at fl 270 and experiencing moderate to severe turbulence a jet stream forecast to be at fl 310 the shortest way to get out of this turbulence by Stable air at mountain top altitude a wind at least 2 knots blowing across mountain ridge. the average width of a jetstream about 300 km its 'thicknes about 12000 ft so you can experience its effects 6000 ft above below core the significant weather chart gives height of core if core given as fl310 then you can experience it up to fl370 down to fl250 if you are flying at fl270 quickest way out of it down. Question 145-32
The jetstream and associated clear air turbulence can sometimes be visually identified in flight Long streaks of cirrus clouds. cirrus clouds are 'stretche the flow of jetstream. Question 145-33
In addition to a lifting action what are two other requirements necessary thunderstorm formation Unstable conditions high moisture content. cirrus clouds are 'stretche the flow of jetstream. Question 145-34
If you have to fly through a warm front when freezing level at 10000 feet in warm air and at 2000 feet in cold air at which altitude the probability of freezing rain lowest Unstable conditions high moisture content. freezing rain can be encounter anywhere between 2000 ft 10000 ft. Question 145-35
From following taf you can assume that visibility at 2055z in birmingham egbb will be egbb 261812 28015g25kt 9999 sct025 tempo 1822 29018g35kt 5000 shrasn bkn010cb prob30 tempo 1821 1500 tsgr bkn008cb becmg 2124 26010kt Not less than 5 km but could be in excess of km. the tempo group used any conditions in wind visibility weather or sky condition which are expected to last generally less than an hour at a time (occasional) are expected to occur during less than half time period thus visibility at 20h55 in birmingham will be not less than 1 5 km (between 18h00 22h00 it could temporarily deteriorate to 5 km between 18h00 21h00 there a 30% possibility that it could temporarily deteriorate to 1 5 km) visibility could also be in excess of 10 km (9999 more than half time period). Question 145-36
The presence of ice pellets at surface evidence that Freezing rain occurs at a higher altitude. the tempo group used any conditions in wind visibility weather or sky condition which are expected to last generally less than an hour at a time (occasional) are expected to occur during less than half time period thus visibility at 20h55 in birmingham will be not less than 1 5 km (between 18h00 22h00 it could temporarily deteriorate to 5 km between 18h00 21h00 there a 30% possibility that it could temporarily deteriorate to 1 5 km) visibility could also be in excess of 10 km (9999 more than half time period). Question 145-37
Continuous updraughts occur in a thunderstorm during Freezing rain occurs at a higher altitude. the tempo group used any conditions in wind visibility weather or sky condition which are expected to last generally less than an hour at a time (occasional) are expected to occur during less than half time period thus visibility at 20h55 in birmingham will be not less than 1 5 km (between 18h00 22h00 it could temporarily deteriorate to 5 km between 18h00 21h00 there a 30% possibility that it could temporarily deteriorate to 1 5 km) visibility could also be in excess of 10 km (9999 more than half time period). Question 145-38
The most dangerous form of airframe icing Freezing rain occurs at a higher altitude. the tempo group used any conditions in wind visibility weather or sky condition which are expected to last generally less than an hour at a time (occasional) are expected to occur during less than half time period thus visibility at 20h55 in birmingham will be not less than 1 5 km (between 18h00 22h00 it could temporarily deteriorate to 5 km between 18h00 21h00 there a 30% possibility that it could temporarily deteriorate to 1 5 km) visibility could also be in excess of 10 km (9999 more than half time period). Question 145-39
The degree of clear air turbulence experienced an aircraft proportional to Intensity of vertical horizontal wind shear. the tempo group used any conditions in wind visibility weather or sky condition which are expected to last generally less than an hour at a time (occasional) are expected to occur during less than half time period thus visibility at 20h55 in birmingham will be not less than 1 5 km (between 18h00 22h00 it could temporarily deteriorate to 5 km between 18h00 21h00 there a 30% possibility that it could temporarily deteriorate to 1 5 km) visibility could also be in excess of 10 km (9999 more than half time period). Question 145-40
At what degree of icing should icao's 'change of course and/or altitude desirable' recommendation be followed Intensity of vertical horizontal wind shear. the tempo group used any conditions in wind visibility weather or sky condition which are expected to last generally less than an hour at a time (occasional) are expected to occur during less than half time period thus visibility at 20h55 in birmingham will be not less than 1 5 km (between 18h00 22h00 it could temporarily deteriorate to 5 km between 18h00 21h00 there a 30% possibility that it could temporarily deteriorate to 1 5 km) visibility could also be in excess of 10 km (9999 more than half time period).
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