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Training and use of airborne weather radar

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Training and use of airborne weather radar

Old 6th Jun 2009, 23:30
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Training and use of airborne weather radar

I remember reading an article in Aviation International News about a study made by one of the weather radar manufacturers into the training given to airline pilots in the use of airborne weather radar.
The study basically concluded that the training given was very poor ,and most pilots had a very poor understanding of how to use their weather radars effectively or that the returns on the display could mean different things if the gain was moved out of calibrated setting.
What training in your radar have you received and what settings do you use and does anybody have a link to the original study?
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Old 7th Jun 2009, 11:40
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The report findings are reproduced here:

Honeywell Aerospace Pilot Survey Findings
By: Ian Goold

Aviation International News >> May 2008
Training

In conducting a survey about the RDR-4000 weather radar, Honeywell safety specialist Dr. Ratan Khatwa asked more than 50 ATP-rated pilots about their experience with weather radar. The average age of the respondents was 52 years; the average flight time was 12,500 hours. The answers these experienced pilots provided were illuminating.

• 62 percent of the pilots surveyed answered correctly that a straight radar beam is not aligned with an aircraft’s current flight level (because of Earth curvature)

• 15 percent mistakenly thought that antenna down-tilt was required to offset a nose-up pitch angle. (That is offset by antenna stabilization.)

• 63 percent did not appreciate the need for weather-radar antennas to be set to compensate for earth curvature, which blocks weather targets beyond, say, 150 nm ahead for nominal cruise altitudes. “Curvature [effects] become noticeable at ranges above 40 nm, and if ignored can lead to weather-image interpretation errors,” said Khatwa.

• 55 percent of pilots did not realize that a weather target falling inside the radar beam will not necessarily be shown in its true color on the display. “The color selected for display is a direct function of the power returned to the receiver. Where the beam is partially filled, the total power returned may not represent the calibrated value associated with the target cell,” he said.

• Five in every eight pilots incorrectly thought green (short-range) radar targets shown near to cruise levels above FL310 need not be avoided. “Typically, at these altitudes, targets are less reflective. At high altitudes, there is a possibility of unstable air and hail above the storm cell. It is therefore not advisable to penetrate the less-reflective part of the storm top,” Khatwa explained.

• 73 percent of flight crew understood that antenna tilt angle does not need to match a climb (or descent) angle to detect weather on their flight path. “The antenna should be pointed at the base of convective weather during climb. Generally, the lower 18,000 feet is the most reflective part of the storm.” Radar can be used to analyze weather characteristics (such as vertical extent of cells) and to avoid strong convective activity. “Returns along the flight-path angle may not provide full indication of storm intensity and turbulence levels [to be encountered within the cell].”

• Almost 90 percent of pilots did not know the range at which their current weather radar was no longer calibrated and did not show returns at their true levels. Radar beams broaden with distance, so a smaller proportion is filled with moisture. “At shorter ranges, returned power is more representative of the target cell, and it is more likely to be displayed at its true calibrated value. Typically, returns are calibrated within a range of 60 to 80 nm.”
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Old 7th Jun 2009, 11:48
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Training WXR

Trained repair engineers and AME in operation & Maintenance of WXR.
In 25 Years I have never had crew allocated bye either airlines or defense forces. There IS a Gap.
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Old 7th Jun 2009, 12:17
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Thank you tubby linton

for opening up THAT CAN OF WORMS..

albeit knowing about the inherent design limits of airborne weather radar for tactical weather avoidance this could become a long overdue and highly interesting and educational thread...
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Old 7th Jun 2009, 12:17
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Hi,

this file is verry interesting, and anyway will enrich your understanding of the system.SmartCockpit - Airline training guides, Aviation, Operations, Safety

rgds
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Old 7th Jun 2009, 12:19
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Wow, I'm impressed at all that technical knowledge but some of us just had to figure it all out on their own using several types of wx radar, I really have no idea how to measure the height of a CB, but I do have a pretty good idea about how to keep an airplane out of the bad stuff.

Deficiencies that I see on the line is not keeping an eye outside the windscreen at the appropriate time, people trying to deviate around planet Earth, and knowing a bit about shapes of returns associated with convective weather.
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Old 7th Jun 2009, 12:52
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training given was very poor
I think non-existent might be a better description.

i have been amazed by the ignorance of WX radar operation I have come across. Sometimes it is just set the range at 160, tilt at 0 (!) and gain in auto and then never touch it! No ideas about evaluating targets by changing settings. Not infrequently I have set the radar as I like only to find a sneaky hand has put it back in the above default position.

Having spent my early career in heavy turboprops (at horrible flight levels) in the tropics, I learnt the hard way and by seeking out information. I learnt a lot from experienced captains but nobody ever formally taught me anything.

In European short haul operations it is not so common to meet wall to wall CB activity so maybe it is way down the list of priorities. Hopefully, whatever the ultimate cause of the AF crash, the discussion of weather it has initiated will make the right people sit up and take notice.
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Old 7th Jun 2009, 13:06
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At different times, I downloaded or acquired a total of more than 2000 pages about the usage of airborne weather radar. And almost 70% of those, I read and understand them throughly. Sometimes they were repeating each other or sometimes they were pointing out a different part of subject. But they were never contradicting.

In my line life of 25 years, I see 95% percent of my collagues are unaware of the correct use of wx radar (mainly tilt). Among them there were very experienced pilots. After some age, it is diffucult to convince them the correct way and kill the old habits of those which heritaged from old-style green painting radars.

At the end, I am not surprised with the result of survey mentioned by TL.

Regards.
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Old 7th Jun 2009, 14:59
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Archie Trammell is considered a bit of a guru when it comes to WX radar. This PPRuNe thread contains an entire article of his from a 1987 issue of Business and Commercial Aviation and makes for interesting reading.

Terminal Area Weather Radar Technique

Also a video of his makes for very interesing viewing - if you can find it.
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Old 7th Jun 2009, 18:33
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tubby linton -


• Five in every eight pilots incorrectly thought green (short-range) radar targets shown near to cruise levels above FL310 need not be avoided. “Typically, at these altitudes, targets are less reflective. At high altitudes, there is a possibility of unstable air and hail above the storm cell. It is therefore not advisable to penetrate the less-reflective part of the storm top,” Khatwa explained.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

It's been my observation, and the observation of most of my coworkers, that the majority of us flying tropical weather do not leave the radars in the calibrated gain settings. The only way to see the "less-reflective part of the storm top" is to get out of the calibrated gain setting.
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Old 7th Jun 2009, 21:23
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Doctor Khatwa made his comments in two presentations ,one n 2007,the other in 2008.The presentations were at European conferences organised by the flight safety foundation.Unfortunately the original documents seem very difficult to access
I agree with him in his assertion that radar training is poor.How many of you know what the calibrated range of your weather radar is?
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Old 7th Jun 2009, 22:26
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Tubby you're right, I think I own one of the only copies of the Collins wx radar pilots manuals in the company and I've asked for wx radar to be covered in refresher training but it never has been. Propilot magazine had a couple of good articles about it recently.
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Old 8th Jun 2009, 15:52
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Color vs. intensity of return is calibrated up to 100 miles out in radars produced since about 1982. It may be less for some models radar; it certainly is for planes with smaller than airline standard 29 inch antenna plate. This is known as STC, Sensitivity Time Control, range. Beyond that, the radar kind of guesses at actual intensity. The farther out a return is detected, the more likely it will display red. Within the STC range, the color/return is calibrated.

Increasing the gain from CAL is effective only within STC range, as the receiver gain is already at max for returns greater than 100 miles.

What has been the experience with the newer Collins and Honeywell radars with automatic tilt and gain?

GB
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Old 8th Jun 2009, 16:29
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The report cited in #2 seems to be true from my personal experience although that is allways anecdotal evidence only. However you have to keep in mind that it is also a report used to promote the first member of Honeywells Intuvue 3D weather-radar family (RDR-4000) which basicly promises to do nearly everything on its own and automaticly. Judging from the product webpage it can indeed provide quite a lot of help to the average pilot, especially if that pilot received the cited bad training.

Would love to hear from someone that uses it how it works in the real world, apparently it is in use on the A380 and will be in use on A350 and Gulfstram 650.
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Old 8th Jun 2009, 16:47
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MyFCOM VOL1 states that the gain adjusts receiver sensitivity to enhance ground mapping in MAP mode only.
In FCOM Vol 2 it states that gain should always be left in automatic,unless specific display enhancement is deemed necessary.
The majority of my colleagues use manual gain outside the terminal area as the radar appears to understate the weather.
I am currently looking for the make and model number of my aircraft's radar so that I can try an find a copy of the manufacturers handbook for it but I have never received any radar specific training.
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Old 11th Jun 2009, 21:29
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to keep the coals hot here...

safetypee ( in the A330 Tech Thread) correctly reminds us all of some severe stuff that had happened years ago, when a commuter a/c manufacturer changed the radar spec from an older high powered cloud slicer to their suppliers new (ever so top top top whatsoever) low powered digital flashlight radar..

make no mistake, that EFIS cockpit looked the same as the older birds..

BUT somebody forgot to inform the crews..

so they were looking at the same radar picture on their MFDs and EHSIs..

the radar had the same controls, in short you wouldn't have been able to tell the difference in the radar by looking at the cockpit..

only to find, well, all of a sudden, two different, highly experienced crews, who never dented a bird before, had hail damage on two different planes of the newer types..within a week of putting the new birds into service..

same clouds, same location, all the same..

EXCEPT, the new radars "led" them directly into the thick of some cells..

well, one should add, that the radar manufacturer also had forgotten to tell the aircraft manufacturer that their old radome spec wouldn't be good enough anymore...(well they had not forgotten, it was written in the installation manuals.., but alas, nobody at the aircraft manufacturer cared to read... sort of had overlooked the small print in the installation manuals..)

anyway, nobody got hurt, the insurance paid for the hail damage on the birds..

but coudda been worse...

Last edited by falconer1; 11th Jun 2009 at 22:23.
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Old 12th Jun 2009, 03:00
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From the training perspective I am somewhat surprised at the apparent poor training comments when modern simulators have the ability to simulate extensive environmental conditions with the associated radar and visual simulations.

Is the apparent poor training being received due to deficiencies within the training programs or are the weather and radar simulations inadequate to provide the level of fidelity required?
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Old 13th Jun 2009, 22:19
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ZFT, guess

we would need a dedicated simulations engineer to answer your question..

or are the weather and radar simulations inadequate to provide the level of fidelity required?
personally never have seen any "good" WX simulations..

and it is a very valid question you pose, though by the nature of things I would think that it is simply impossible to simulate a true WX condition, "true" meaning that all the unknowns of a dynamic target and the reaction of a specific WX radar / airframe / avionics combination could be put into a simulation model..

maybe its possible but I doubt it..

all other stuff you can simulate pretty well by now, but WX targets, probably would need a quantum computer just to calculate all possibilities..

and then you still would not know, whether the crews interpretation of the WX image could be transferred to the real world..whether you would have a hit or a miss in reality..too complex, too many factors involved..

how do you want to simulate attenuation and its associated problems in the sim???
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Old 14th Jun 2009, 00:16
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In my experience, the all digital units are part of the problem.

Back in the old days of analogue radar, more attention was paid to finessing the thing and using several settings and subsequent screen paints to interpret the returns. Intensity, tilt, range and sensitivity were all put to good use.

Digital radars are treated more like mysterious boxes in training with little insight offered into their internal workings. This unshared insight has the potential of unlocking the finer points of use, particularly when operating at the limits of the units performance.

Across the board, system concepts and theories used to be covered in depth. Unfortunately with today's highly automated aircraft, the dumbing down philosophy marches on.
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Old 14th Jun 2009, 00:26
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This is a copy and paste from the latest Rockwell Collins WXR-2100 Multiscan Radar manual equipped in my fleet which begs you to leave it in fully auto gain.


"The top of a thunderstorm is composed entirely of ice crystals (glaciated) and reflects very little radar energy. At temperatures less than –40 oC, liquid water no longer exists and only ice crystals are present. The altitude at which this temperature occurs varies depending on the time of day, time of year and based on latitude and longitude. Ice crystals are formed when the positive hydrogen atoms and the negative oxygen atom of water molecules lock or freeze the molecules into an ice crystal lattice. Ice crystal molecules are not able to change orientation to respond to and reflect radar energy. The middle portion of a thunderstorm occurs above the freezing level (0o C) and up to the altitude where the outside air temperature drops below –40oC. This section of the storm is composed of a combination of ice crystals and super cooled water. The super cooled water provides moderate reflectivity, but some reflective energy will be lost due to the presence of ice crystals. The top of this section of the storm is often referred to as the wet top or radar top of the thunderstorm. Building thunderstorms also have a turbulence bow wave that extends well above the visible top of the thunderstorm. The bow wave may cause severe turbulence but is completely invisible to radar."

Having read that, I found myself avoiding cells that are sometimes 4 to 5000 feet below me or cells that are not even there...so guess what? ...2 clicks out of auto gain and you really have the correct picture on the nav display, but I leave the F/Os settings on auto just in case the bow wave is too obvious...



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