Storm ice suspected in Etihad A340 cruise incident
Sorry to cloud the issue, pun intended, but the advice my company has from Boeing is that ice crystals do NOT always paint on the weather radar. So it's a tad unfair to lay the blame on crews who one hopes would have actively altered the range and tilt on the weather radar system.
I've seen some huge CBs that didn't paint at all and was thankful that being VMC we could see and avoid. At night I'm convinced I encountered the tops of such cells judging from the St Elmo's fire and turbulence. In one instance we were most definitely scanning at different ranges and tilt angles.
The other thing that my company has instigated is a flame out mitigation procedure on advice from Boeing. Basically it's Nacelle Anti Ice on in moisture during the descent and Wing AI as well below F220. If it proves one point is that even the manufacturers constantly review and revise their procedure in the light of experience.
I've seen some huge CBs that didn't paint at all and was thankful that being VMC we could see and avoid. At night I'm convinced I encountered the tops of such cells judging from the St Elmo's fire and turbulence. In one instance we were most definitely scanning at different ranges and tilt angles.
The other thing that my company has instigated is a flame out mitigation procedure on advice from Boeing. Basically it's Nacelle Anti Ice on in moisture during the descent and Wing AI as well below F220. If it proves one point is that even the manufacturers constantly review and revise their procedure in the light of experience.
pretty obvious that this is a one-sentence simplified summary.
there are some pilots who actually know what to do - one could try asking them.
Per Ardua ad Astraeus
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How does one differentiate those old hands who think they know what to do and are right and those who think they know what to do but are simply so-far-so-lucky?
Often it takes an enquiry or two to find out what your colleagues have been taught or are looking for/at if their radar settings dont make sense.
Explaining in a nice mannered way to crew new to it all the advantages/disadvantages of 'auto tilt' v 'manual tilt' doesnt take much effort and often times the light bulb comes on.
Look low to high, isolate the weather from the ground returns, use a lower scale for accurate close in avoidance, use all the cues you can to establish how high and powerful the TS system (lightning, radar return shape size & intensity, ADF needles, radio static & interference, st elmos fire, ragged edged rotors, get a sighting on a TS head at night by putting your nose on the combing with the cockpit lights down, watch for indications of high altitude precip & ice crystals in ypur headlights, watch for SAT increases) prepare yourselves, the jet & cabin and dont overfly any TS cell at night in particular - any hint of a return anywhere close to level tilt at high level especially at night is an avoid
I am always happy to do the ITCZ/TS slalom course.
Explaining in a nice mannered way to crew new to it all the advantages/disadvantages of 'auto tilt' v 'manual tilt' doesnt take much effort and often times the light bulb comes on.
Look low to high, isolate the weather from the ground returns, use a lower scale for accurate close in avoidance, use all the cues you can to establish how high and powerful the TS system (lightning, radar return shape size & intensity, ADF needles, radio static & interference, st elmos fire, ragged edged rotors, get a sighting on a TS head at night by putting your nose on the combing with the cockpit lights down, watch for indications of high altitude precip & ice crystals in ypur headlights, watch for SAT increases) prepare yourselves, the jet & cabin and dont overfly any TS cell at night in particular - any hint of a return anywhere close to level tilt at high level especially at night is an avoid
I am always happy to do the ITCZ/TS slalom course.
Last edited by ramble on; 6th Apr 2013 at 02:20.
radar ADF needles
although I presume you mean ADF needles as a means of detecting the direction of a CB. I vaguely recall the wandering of ADF needles to point at lighning areas needed the ADF be tuned to a very low frequency? Is that a myth or does data support this?
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[QUOTE]Post 13 - Centaurus - I haven't operated modern radar but certainly we used maximum manual gain at high altitude cruise in the 737 with Collins WXR-700 radar over the Pacific and that would pick up CB tops which had little moisture. It would show as a tiny echo at 40 miles or thereabouts but enough to alert an alert pilot of something big ahead. All you did then was use the tilt control to scan below and pick up the body of the CB and take it from there - ie divert around it. The auto gain control was useless at high altitude which is why MAX gain was used to scout for CB tops.[/QUOTE]
That is the preferred technique for 50%+, and perhaps as high as 90%, of pilots at my airline.
That is the preferred technique for 50%+, and perhaps as high as 90%, of pilots at my airline.
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Well, Airbus has three great pubs....
Well, Airbus has three great publications:
Flight Operations Briefing Notes
Adverse Weather Operations
Optimum Use of the Weather Radar
Getting to Grips with Surveillance
(Chapter 6)
15th Performance and Operations Conference
Puerto Vallarta 23-27 April 2007
Ice Crystals: An Environmental Threat
Operations in Icing Conditions in Flight
Presented by Helene Rebel
Head of A330/340 Operational Standard
And, there's a Boeing publications, too.
The Ice Particle Threat to Engines in FLight
By Jeanne G. Mason
Boeing Commercial Airplanes
Seattle, WA USA 98124
(Other authors listed, as well....not mentioned, here, for brevity only)
Fly safe,
PantLoad
Flight Operations Briefing Notes
Adverse Weather Operations
Optimum Use of the Weather Radar
Getting to Grips with Surveillance
(Chapter 6)
15th Performance and Operations Conference
Puerto Vallarta 23-27 April 2007
Ice Crystals: An Environmental Threat
Operations in Icing Conditions in Flight
Presented by Helene Rebel
Head of A330/340 Operational Standard
And, there's a Boeing publications, too.
The Ice Particle Threat to Engines in FLight
By Jeanne G. Mason
Boeing Commercial Airplanes
Seattle, WA USA 98124
(Other authors listed, as well....not mentioned, here, for brevity only)
Fly safe,
PantLoad
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First....
First, flight through the tops of thunderstorms should be avoided.
There are several reasons why....turbulence, icing, etc.
Second point, turbulence can be heavy even as high as 5000 feet
above the tops of thunderstorms. Therefore, in most cases (most
thunderstorms), attempting to top turbulence of thunderstorms in
an airliner is futile....and possibly dangerous (buffet margin?)
Third, having said the above, proper use of RADAR is critical. You
have to be able to detect and then circumnavigate (usually) the
storm.
Tilt is the most critical control on the RADAR control panel. Since
RADAR does not very well "paint" some forms of moisture, it
is important to adjust the RADAR tilt to point the signal to the
most reflective section of the storm. This is approximately the
freezing level....maybe slightly below.
Thus, in order to do this, the tilt angle is dependent on the aircraft's
altitude and the distance in front of the aircraft the storm is that you're
trying to paint.
Example...if you're at FL250 and climbing...and looking at a group of
storms, say, 100 miles in front of you, you're tilt will be relatively
high.
In contrast, if you're at FL390 and trying to paint a storm, say, 20
miles in front of you, your tilt will be pretty low.
Again, you want to point the signal at the most reflective part of the
storm.
Some use the technique of adjusting the gain....and running the tilt
to a relatively high angle. This is not recommended....please refer to
chapter six of Getting to Grips with Surveillance. There are several
important functions that you lose when you bring the gain out of
AUTO or CAL. Don't misunderstand....it is OK to move the gain out
of AUTO or CAL....for temporary analysis of the weather....but, as soon
as finished with that, go back to AUTO/CAL. The functions you lose
when out of AUTO/CAL vary with RADAR brand (i.e. Honeywell or
Collins) and RADAR type (i.e. Multi-Scan or non-Multi-Scan).
The previous-mentioned pubs have really good information.
Fly safe,
PantLoad
There are several reasons why....turbulence, icing, etc.
Second point, turbulence can be heavy even as high as 5000 feet
above the tops of thunderstorms. Therefore, in most cases (most
thunderstorms), attempting to top turbulence of thunderstorms in
an airliner is futile....and possibly dangerous (buffet margin?)
Third, having said the above, proper use of RADAR is critical. You
have to be able to detect and then circumnavigate (usually) the
storm.
Tilt is the most critical control on the RADAR control panel. Since
RADAR does not very well "paint" some forms of moisture, it
is important to adjust the RADAR tilt to point the signal to the
most reflective section of the storm. This is approximately the
freezing level....maybe slightly below.
Thus, in order to do this, the tilt angle is dependent on the aircraft's
altitude and the distance in front of the aircraft the storm is that you're
trying to paint.
Example...if you're at FL250 and climbing...and looking at a group of
storms, say, 100 miles in front of you, you're tilt will be relatively
high.
In contrast, if you're at FL390 and trying to paint a storm, say, 20
miles in front of you, your tilt will be pretty low.
Again, you want to point the signal at the most reflective part of the
storm.
Some use the technique of adjusting the gain....and running the tilt
to a relatively high angle. This is not recommended....please refer to
chapter six of Getting to Grips with Surveillance. There are several
important functions that you lose when you bring the gain out of
AUTO or CAL. Don't misunderstand....it is OK to move the gain out
of AUTO or CAL....for temporary analysis of the weather....but, as soon
as finished with that, go back to AUTO/CAL. The functions you lose
when out of AUTO/CAL vary with RADAR brand (i.e. Honeywell or
Collins) and RADAR type (i.e. Multi-Scan or non-Multi-Scan).
The previous-mentioned pubs have really good information.
Fly safe,
PantLoad
I presume you mean ADF needles as a means of detecting the direction of a CB. I vaguely recall the wandering of ADF needles to point at lighning areas needed the ADF be tuned to a very low frequency? Is that a myth or does data support this?
Last edited by compressor stall; 6th Apr 2013 at 11:36.
