"Area of light to moderate precipitation ahead..."

Discussion in 'Change to my Frequency...' started by ChiefPilot, Aug 14, 2017.

  1. ChiefPilot

    ChiefPilot Pre-takeoff checklist

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    I've heard controllers kindly advise of areas of precip for some time but was wondering yesterday if it was the result of controllers being nice, technology enabling them to see precip better, or perhaps something else. Are these advisories now policy-driven? I started wondering if maybe this changed after Scott Crossfield's crash?
     
  2. Velocity173

    Velocity173 Final Approach

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    Well, nothing new since Crossfield's crash. The controller's are required to issue precip intensities to pilots if equipped. The older analog ASRs (ASR-8) and PARs don't have that capability so they issue an "area of precipitation." Newer digital radars (ASR-9/11) have discriminators that show levels (1-6) that they convert to light, moderate,heavy or extreme.
     
    Last edited: Aug 14, 2017
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  3. luvflyin

    luvflyin Final Approach

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    Even mean controllers do it. It is policy driven. The NTSB did find ATC a factor in that accident so it's likely there may have been some changes to policy as a result. There have been a lot of changes as technology gets better at displaying weather.

    2−6−4. ISSUING WEATHER AND CHAFF AREAS
    a. Controllers must issue pertinent information on observed/reported weather and chaff areas to potentially affected aircraft. Define the area of coverage in terms of:

    1. Azimuth (by referring to the 12−hour clock) and distance from the aircraft and/or
    2. The general width of the area and the area of coverage in terms of fixes or distance and direction from fixes.
    NOTE−Weather significant to the safety of aircraft includes conditions such as funnel cloud activity, lines of thunderstorms, embedded thunderstorms, large hail, wind shear, microbursts, moderate to extreme turbulence (including CAT), and light to severe icing.
    REFERENCE−AIM, Paragraph 7−1−14, ATC Inflight Weather Avoidance Assistance.
    PHRASEOLOGY−WEATHER/CHAFF AREA BETWEEN (number) O’CLOCK AND (number) O’CLOCK (number) MILES, and/or (number) MILE BAND OF WEATHER/CHAFF FROM (fix or number of miles and direction from fix) TO (fix or number of miles and direction from fix).
    b. Inform any tower for which you provide approach control services of observed precipitation on radar which is likely to affect their operations.
    c. Use the term “precipitation” when describing radar−derived weather. Issue the precipitation intensity from the lowest descriptor (LIGHT) to the highest descriptor (EXTREME) when that information is available. Do not use the word “turbulence” in describing radar−derived weather.
    1. LIGHT.
    2. MODERATE.
    3. HEAVY.
    4. EXTREME.
    NOTE−Weather and Radar Processor (WARP) does not display light intensity.
    PHRASEOLOGY−AREA OF (Intensity) PRECIPITATION BETWEEN (number) O’CLOCK AND (number) O’CLOCK, (number) MILES, MOVING (direction) AT (number) KNOTS, TOPS (altitude). AREA IS (number) MILES IN DIAMETER.
    EXAMPLE−1.“Area of heavy precipitation between ten o’clock and two o’clock, one five miles. Area is two five miles in diameter.”
    2.“Area of heavy to extreme precipitation between ten o’clock and two o’clock, one five miles. Area is two five miles in diameter.”
    REFERENCE−P/CG Term− Precipitation Radar Weather Descriptions.
    d. When precipitation intensity information is not available.
    PHRASEOLOGY−AREA OF PRECIPITATION BETWEEN (number) O’CLOCK AND (number) O’CLOCK, (number) MILES. MOVING (direction) AT (number) KNOTS, TOPS (altitude). AREA IS (number) MILES IN DIAMETER, INTENSITY UNKNOWN.
    EXAMPLE−“Area of precipitation between one o’clock and three o’clock, three five miles moving south at one five knots, tops flight level three three zero. Area is three zero miles in diameter, intensity unknown.”
    NOTE−Phraseology using precipitation intensity descriptions is only applicable when the radar precipitation intensity information is determined by NWS radar equipment or NAS ground based digitized radar equipment with weather capabilities. This precipitation may not reach the surface.
    e. EN ROUTE. When issuing Air Route Surveillance Radar (ARSR) precipitation intensity use the following:
    1. Describe the lowest displayable precipitation intensity as MODERATE.
    2. Describe the highest displayable precipitation intensity as HEAVY to EXTREME.
    PHRASEOLOGY−AREA OF (Intensity) PRECIPITATION BETWEEN (number) O’CLOCK and (number) O’CLOCK, (number) MILES, MOVING (direction) AT (number) KNOTS, TOPS (altitude). If applicable, AREA IS (number) MILES IN DIAMETER.
    EXAMPLE−1.“Area of moderate precipitation between ten o’clock and one o’clock, three zero miles moving east at two zero knots, tops flight level three seven zero.
    2.“Area of moderate precipitation between ten o’clock and three o’clock, two zero miles. Area is two five miles in diameter.”
    f. Controllers must ensure that the highest available level of precipitation intensity within their area of jurisdiction is displayed unless operational/ equipment limitations exist.
     
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  4. Shawn

    Shawn En-Route

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    Was flying with guy and ATC advises exactly that...his response?..."in sight, head for the plane wash, 456."
     
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  5. James331

    James331 Touchdown! Greaser!

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    Also keep in mind, though I bet their system is better than ADSB wx, it's a bit of a way from real onboard radar
     
  6. flyingron

    flyingron Touchdown! Greaser!

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    I always respond with "thank you" unless I need more information.
     
  7. frfly172

    frfly172 Touchdown! Greaser!

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    Very helpfull ,when flying a composite prop,get vectors out of precipitation or land if given enough notice.
     
  8. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser!

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    So what is your response if given ppte ahead? Unless convective I have only asked for turns if > moderate.
    (I find atc radar over-reports the level)
     
  9. flyingron

    flyingron Touchdown! Greaser!

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    If I'm VFR, same thing. If IFR and want to deviate, then I ask for the turn.
     
  10. Velocity173

    Velocity173 Final Approach

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    I had an Army controller issuing light to moderate on the restricted area one night. I acknowledged and we kept trucking along. Finally he became exasperated that we weren't deviating and asked if the rain was that bad or his radar was inaccurate. I told him, there's areas of moderate but it's not convective and we still had 3 miles vis (barely).

    That's essentially it. If I'm VFR and I can maintain my min vis and it doesn't have lightning, I'm going thru.
     
    Last edited: Aug 17, 2017
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  11. ChiefPilot

    ChiefPilot Pre-takeoff checklist

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    What I've learned is that TRACON radar is realtime, while ARTCC is nexrad. I'd believe TRACON over ADS-B or ARTCC. And has been pointed out, ARTCC (like ADS-B) is subject to "Nexraggeration" :)
     
  12. Velocity173

    Velocity173 Final Approach

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    Depends. Analog TRACON is essentially an immediate return. A blob with no intensity. Digital TRACONs have a 30 sec delay for the processor to provide a discriminator (level 1-6). No idea how long centers take. I don't think their Doppler weather is even coming off their surveillance radar (ARSR-4) sweep (12 secs).
     
    Last edited: Aug 17, 2017
  13. ChiefPilot

    ChiefPilot Pre-takeoff checklist

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    According to the document at https://www.faasafety.gov/gslac/alc/libview_normal.aspx?id=6581 the approach facilities are "near real time" while ARTCCs have a NEXRAD overlay up to six minutes old.
     
  14. Velocity173

    Velocity173 Final Approach

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    I guess that depends on the definition of "near real time." Analog weather is like an aircraft return. Speed of light and It's refreshed roughly every 4.7 secs if using a single source radar. Digital, is also refreshed roughly every 4.7 secs for aircraft targets but the weather goes through a reflectivity processor that takes 30 secs to update. I suppose that could be considered "near real time." Actually preferred the depiction of analog vs digital but that's getting phased out in favor of digital.

    I knew center's stuff was old but never got any solid answers from them on how old. The old days they could use their actual ARSR-4 for weather but it looks like they're all using NEXRAD now.
     
    Last edited: Aug 17, 2017
  15. Velocity173

    Velocity173 Final Approach

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    IMG_2426.JPG Digital with the new STARS depiction. The older digital with ARTS was too "blocky" in my opinion.
     
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  16. Getonit

    Getonit Pre-takeoff checklist

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    I think the controllers are being over cautious on some of their weather reporting, not that anything wrong with that but it is a balance. I was flying as copilot in a Hawker and they called out precip, barely green on the radar and the captain, being the ***** he was, was turning around imaginary stuff, it didn't even paint. I didn't care for him if you can tell from my tone.
     
  17. Velocity173

    Velocity173 Final Approach

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    FYI for phraseology prior to Spring of 2006. Intensity replaced level.

    EXAMPLE−

    1. “Level five weather echo between eleven o’clock and one o’clock, one zero miles. Moving east at two zero knots, tops flight level three niner zero.”

    2. “Level four weather echo between ten o’clock and two o’clock, one five miles. Weather area is two five miles in diameter.”

    3. “Level four and five weather echoes between ten o’clock and two o’clock, one five miles. Weather area is two five miles in diameter.”

    4. “Level two through four weather echoes between ten o’clock and two o’clock, one five miles. Weather area is two five miles in diameter.”
     
  18. wsuffa

    wsuffa Touchdown! Greaser!

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    Down between Austin and San Antonio they'd even warn you about the swarms of bats.
     
  19. danhagan

    danhagan Cleared for Takeoff

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    Years ago on a July 4th trip in the morning from El Paso to California, FSS indicated VFR entire trip with slight chance of a light shower near PHX. That forecast turned into departing in light rain and haze all the way to AZ. Had the same controller the entire time and almost nobody else on his scope (low level flyer I guess). He then informs me heavy to extreme extending from just south of PHX to Blythe along the I-10 corridor (non-restricted route) and "do you have the cells at your 9:00, 3:00 and 6:00? Say intentions?" Didn't see it was building behind me. My response, landing Marana now. Waited on the ground a little over an hour and launched again. "My" controller just came back on from break, and indicated things didn't look much better around PHX and could I accept direct Yuma, through all the restricted airspace ... I took it and about 3 seconds later several others requested to drop off their IFR flight plan and take the same routing. From the air, the stuff to the north was UGLY from over 100 miles away. There were 6 of us in trail on the route with occasional light precip ... much better. Great ATC work!
     
  20. Pilawt

    Pilawt Final Approach

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    A few months ago I was enroute from Sedona back to Goodyear on Flight Following, and ATC asked if I had the area of precipitation in sight, five miles ahead, for the next fifteen miles of my route.

    I looked real hard, but this was all I saw:

    Screen Shot 2017-08-22 at 6.08.50 PM.png

    When I got home I pulled up my trip in Flightaware, and sure enough, this must have been was the controller was asking me about:

    Screen Shot 2017-08-22 at 6.12.21 PM.png

    It must be some artifact in the system (terrain maybe?), because if you look at Flightaware right now, that identical pattern of "precip" still shows up, months later, on this crystal-clear day.
     
  21. pburger

    pburger Pre-takeoff checklist

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    I was returning from a group lunch run a couple of years ago, and was talking on 122.75 with one of the other guys who was about a mile or so off my right wing. We both had XM Wx back then, and he asked if I saw the weather paining on my iPad. I said I did, but that there was nothing out the front windshield. I remember telling him it must be old data or well above us. We were flying below 3000. He kept talking about the fact that there was a red area. He said, "I'll fly through green, and maybe through yellow, but I WILL NOT fly through red!". He then broke off and went on some wild azz deviation around a red spot on his iPad, while we continued straight ahead through clear skies with a smooth ride. No precip, no downdrafts, no nothin'. Talk about a child of the magenta line...
     
  22. Velocity173

    Velocity173 Final Approach

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    Yeah, looks like terrain. They have tools such as Moving Target Indicator that eliminate most of that though. Sometimes just the movement from windmill farms will produce returns on the scope. Even a temperature inversion will produce Anomalous Propagation that can look like precip.
     
  23. arnoha

    arnoha Cleared for Takeoff

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    Slight necropost, but just noticed that keyboard...

    Is it as awful as it looks? ABC-order keyboard, totally nonstandard. Numeric keypad upside-down. Fully rectilinear. They had room for a zero bar, but blanked the keys instead? Everything is just crammed together in a way that seems to imply that the only way to use it is single-finger. Space bar and enter and other such keys smack in the middle?

    Or I just don't understand how it's being used, and this is actually ideal.
     
  24. Velocity173

    Velocity173 Final Approach

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    Not sure why the ABC format but it's what I used in the older systems as well. On the radar approach position, there really isn't a need for typing in a lot of words so the keys are mostly just single or two finger entries. A handoff consists of one key for the aircraft tag, a "handoff" key and then one key for the receiving facility. Even scratchpads are pretty simple, such as PA/TR/11; precision approach radar, touch and go to remain with radar on button (freq) eleven.

    The flight data input output computer or "FIDO" uses the QWERTY format though. I suppose since its designed for flight plan entry / amendments with more words, it's the better format for that. Don't know.
     
  25. Radar Contact

    Radar Contact Cleared for Takeoff

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    And it case I missed it above...

    On our 6 level systems described we are required to issue it via the following:
    Level 1=Light
    Level 2=Moderate
    Level 3&4=Heavy
    Level 5&6=Extreme
     
  26. arnoha

    arnoha Cleared for Takeoff

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    The telephone style numbers also confuse me. I would have expected calculator/computer ordering.
     
  27. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser!

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    Controllers, tell us what you have seen;
    Have you seen anyone go through Extreme?
    Have you seen anyone go through Heavy?
    What were the circumstances, the reports - if you were talking to them?
    I've always done my best to avoid even moderate, depending on the airplane and passengers aboard. Light has never been a problem.
    (And of course you can go under or over some terrible radar pics and experience little.)
     
  28. Velocity173

    Velocity173 Final Approach

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    The one base (NKX) that I worked that did have WX discriminators, I never saw heavy or extreme. San Diego gets mostly light rain, when they do get it.

    At NBC, we had analog ASR-8 radar so no telling what the actual level was. Just amber "cauliflower" that builds during the day. After sitting on position for hours at a time, you can kinda tell what's convective and what's not but you still have to issue the standard "I don't show convective activity, only areas of precipitation." I don't recall any aircraft that intentionally flew through what I believed to be Tstorms. Pretty much all of them either deviated on their own, or requested vectors. I remember one distinct occasion where I vectored a Navajo between some cells. I thought I gave him a good gap but he came back with "approach, don't send anyone else through that area again! We just just got severe turbulence." :(

    Friend of mine in ATL was working some of this traffic.


     
    Last edited: Oct 23, 2017
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  29. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser!

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    The weather blocks; the spinning begins!
     
  30. Radar Contact

    Radar Contact Cleared for Takeoff

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    Most the jets will go through heavy. They usually avoid extreme. Sometimes depending on their tilt or feeling at the time they may request to deviate around build ups that show light and moderate on our scopes. Just depends.

    While flying I don't mind light and depending on other factors (i.e. likely hood of rapid development, etc) will do moderate. A lot of times light may not even have precip reaching the ground and moderate may just be steady rain. I avoid all heavy and extreme (unless I'm VMC and can avoid rain shafts with an out).

    Unfortunately I've seen 2 light GA planes fly into extreme with an unfortunate outcome (neither were under my control).

    Parting story, I was holding SWA planes for MDW once with extreme on the final and an airliner with origins south of the US wanted to attempt the approach even after I explained the wx on the final and that all other aircraft were holding. When he got into the heart of it at 5000msl his altitude whent XXX which indicates the climb and/or descent rates are so great that the radar can't keep up. I got a hit at 3000 then a few seconds later I got a hit at almost 7000 and the pilot in a very scared voice requested vectors out of there. My first thought, no sh*t. My second thought was what it must of been like in the back during that in the black clouds with lighting popping all around you.
     
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