Wx aviodance.
411A, (and Towerdog)
quote from 411A
And from comments, some think that a jet aeroplane will "fall apart" when going thru a low level cloud. Hey guys, it may come as a big surprise that DC-6's and Stratocruisers plowed thru the murk and actually came out on the other side in one piece
unquote
For your info, some accident reports are summarised below.
14 Feb 1953 National Airlines Douglas DC-6 Reg no N90893. Crashed due to structural failure after flying into a storm whilst en-route from Tampa to New Orleans.
22 Aug 1954 Braniff Airways Douglas DC-3 Reg no N61451. Crashed shortly after take off from Waterloo USA whilst trying to traverse a thunderstorm by flying towards a ‘bright spot’
03 May 1968, Braniff Airways Lockheed L-188A Electra Reg N9707C. Crashed due to structural failure after flying into a thunderstorm en-route from Houston to Dallas. (This crash prompted major reviews of storm avoidance training and procedures.)
06 Oct 1981 KLM Fokker F-28 Fellowship 4000 Reg no. PH-CHI crashed due to structural failure after flying through an area of thunderstorm activity whilst en-route from Rotterdam to Eindhoven. (The crew had requested to deviate around weather.)
02 Aug 1985, Delta Airlines L – 1011 TriStar Reg no. N726DA. Crashed after flying into a microburst on approach to Dallas.
If you want to see more like this, keep flying into CBs. If you still think that it’s OK to do that, perhaps that Sunday VFR flying you keep going on about is more appropriate for you!
I’m still not advocating avoiding all weather – just the stuff that’s nasty!
quote from 411A
And from comments, some think that a jet aeroplane will "fall apart" when going thru a low level cloud. Hey guys, it may come as a big surprise that DC-6's and Stratocruisers plowed thru the murk and actually came out on the other side in one piece
unquote
For your info, some accident reports are summarised below.
14 Feb 1953 National Airlines Douglas DC-6 Reg no N90893. Crashed due to structural failure after flying into a storm whilst en-route from Tampa to New Orleans.
22 Aug 1954 Braniff Airways Douglas DC-3 Reg no N61451. Crashed shortly after take off from Waterloo USA whilst trying to traverse a thunderstorm by flying towards a ‘bright spot’
03 May 1968, Braniff Airways Lockheed L-188A Electra Reg N9707C. Crashed due to structural failure after flying into a thunderstorm en-route from Houston to Dallas. (This crash prompted major reviews of storm avoidance training and procedures.)
06 Oct 1981 KLM Fokker F-28 Fellowship 4000 Reg no. PH-CHI crashed due to structural failure after flying through an area of thunderstorm activity whilst en-route from Rotterdam to Eindhoven. (The crew had requested to deviate around weather.)
02 Aug 1985, Delta Airlines L – 1011 TriStar Reg no. N726DA. Crashed after flying into a microburst on approach to Dallas.
If you want to see more like this, keep flying into CBs. If you still think that it’s OK to do that, perhaps that Sunday VFR flying you keep going on about is more appropriate for you!
I’m still not advocating avoiding all weather – just the stuff that’s nasty!
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Agreed propulike, the nasty ones should certainly be avoided...but you must remember that your aeroplane is not the only one in the sky...cooperate with the ATC controllers and all will survive.
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so 411a, what is your defination of "a nasty one".
If you were flying through an area containing CB`s that appeared red on a radar how would you decide which one was nasty?
I would consider all red returns on a properly set up radar
(i.e. correct gain setting) extremly hazardous to fly through,
but maybe I`m missing something!
If you were flying through an area containing CB`s that appeared red on a radar how would you decide which one was nasty?
I would consider all red returns on a properly set up radar
(i.e. correct gain setting) extremly hazardous to fly through,
but maybe I`m missing something!
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Well fishy..lets take an example...Singapore, twenty miles west, six thousand descending, all the radar screen shows red (general rain showers in the vicinity) from the aeroplane to the runway.
What are you going to do? Hold for the rain to move away (could take hours, how much fuel do you have....all good questions, and I have been in this situation many times there...the answer is use contour to deviate 'round the larger buildups and accept the generally rough ride. Weather is part and parcel of the airline pilots job, like it or not.
OTOH, for a pilot to go off an a tangent, without advising ATC before hand.....is NOT a good idea, for him OR the other aircraft in the TMA.
You do your best...and use the experience at hand. That is what you are paid the big bucks for.
What are you going to do? Hold for the rain to move away (could take hours, how much fuel do you have....all good questions, and I have been in this situation many times there...the answer is use contour to deviate 'round the larger buildups and accept the generally rough ride. Weather is part and parcel of the airline pilots job, like it or not.
OTOH, for a pilot to go off an a tangent, without advising ATC before hand.....is NOT a good idea, for him OR the other aircraft in the TMA.
You do your best...and use the experience at hand. That is what you are paid the big bucks for.
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WF
I can recall about half a dozen incidents which TCAS has caused. It would be most unwise to rely on it for this purpose and if we have got to the point where we have to rely on it then we have got way past the point where safety is being compromised to move more traffic. That is something we keep telling the public we will never do.
Yesterday I had two Heavies running into OCK 5 miles apart, 1000' separated. The first asked to go right for wx and deviated by about 2 miles. The second went straight "through" what ever the first avoided. There was only 15kts of wind , so any wx wouldn't have moved 2 miles in 1 minute. I asked if it was to avoid CB activity (none being reported by Met.) and he said yes, tops about FL100. I thought CBs went much higher than that or have I got something wrong there? Topping out at that level, was this not a towering CU, and far less significant in terms of wx? The point I have been making is that many a/c are deviating for comfort rather than safety and it is draining our capacity.
Pegasus 77
If you wouldn't avoid when we have said no due traffic then you are saying that the traffic confliction rates higher than the wx danger. In that case why are so many people prepared to deviate without being sure that there is no traffic in the way first?
Several things need to be done if this issue is to be resolved:
1. Provide NATS ATCOs with wx radar so that we can see your needs.
2. If we wish to retain our capacity, crews must only request for safety, not comfort.
3. R/t loadings must be reduced. At Heathrow this can be achieved by Mixed mode and a second Final Director.
This is a safety issue and it has to come before politics.
Point 4
I can recall about half a dozen incidents which TCAS has caused. It would be most unwise to rely on it for this purpose and if we have got to the point where we have to rely on it then we have got way past the point where safety is being compromised to move more traffic. That is something we keep telling the public we will never do.
Yesterday I had two Heavies running into OCK 5 miles apart, 1000' separated. The first asked to go right for wx and deviated by about 2 miles. The second went straight "through" what ever the first avoided. There was only 15kts of wind , so any wx wouldn't have moved 2 miles in 1 minute. I asked if it was to avoid CB activity (none being reported by Met.) and he said yes, tops about FL100. I thought CBs went much higher than that or have I got something wrong there? Topping out at that level, was this not a towering CU, and far less significant in terms of wx? The point I have been making is that many a/c are deviating for comfort rather than safety and it is draining our capacity.
Pegasus 77
If you wouldn't avoid when we have said no due traffic then you are saying that the traffic confliction rates higher than the wx danger. In that case why are so many people prepared to deviate without being sure that there is no traffic in the way first?
Several things need to be done if this issue is to be resolved:
1. Provide NATS ATCOs with wx radar so that we can see your needs.
2. If we wish to retain our capacity, crews must only request for safety, not comfort.
3. R/t loadings must be reduced. At Heathrow this can be achieved by Mixed mode and a second Final Director.
This is a safety issue and it has to come before politics.
Point 4
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I would want to avoid any Cu type cloud that was topping out at FL100. CBs do get really high, but those sort of heights generally don't occur in the UK that often. Whether its TCu or CB can be something of an academic exercise because you can get an awful lot of turbulence in both. As for prioritising wx avoidance over traffic conflict, well you'll hate me for saying this but most people look at TCAS. We've generally got a reasonable idea whats within 10 miles of us and +/- 7000 feet, and if it comes down to flying through a really nasty one one has to consider what the greatest threat to the aircraft is; the certainty of hitting very bad wx or the possibility of conflicting with another aircraft. Now that would be an interesting one to defend in court, but I'd opt to avoid the immediate danger and worry about the loss of seperation if/when it happens. As for the heavies in trail you mention, well I don't know what the resolution of your radars are but a few hundred feet lateral seperation could make the difference between skirting the edge or ploughing right through so it's possible one didn't actually hit it.
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Completely wrong 411A. I'm very much in the category of continue if at all possible, avoid if convenient to ATC. The latter is for comfort, the former for safety. Unlike you I do not have blind faith that the cabin and its contents are completely secure. Flying into a CB invites all manner of things to get airborne, from the floors and the overhead lockers, which could injure a person. It also raises a number of technical risks beyond the obvious rain and hail damage. The airframe probably won't break up, but severe turbulence can and does lead to airframe overspeeds and angle of attack protection being activated. Both of these events will cause the autopilot to drop out in my type. In a busy terminal area this could lead to highly dangerous altitude busts, particularly as vertical seperation is significantly less in real distance terms than lateral seperation. These sort of events are likely to leave the crew with little or no spare capacity to respond to ATC instructions, exacerbating the situation further still. In the rare instances of extreme weather in the UK I'd much sooner have a controlled unauthorised departure from ATC clearance than an uncontrolled and unexpected one. If that messes up the approach sequencing then I'm really sorry, but it's going to cause less disruption than an unauthorised departure followed by a medical emergency because someones now wearing their wheelie bag as a hat and the stewardess broke a leg.
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Well HandSolo, have to agree with you about one thing....no matter WHAT you tell the cabin, they will invariably do their own thing. Recall years ago on departure from CMB, told everyone in the cabin to "sit tight and stay belted in" because of wx ahead on the departure track. Sure enough, one hostie in the rear cabin decides to start drinks service and...presto, one nasty thump and the whole cart was upside down with many broken bottles....and this was in the clear, with no returns on the 'scope. Sometimes no matter what, s..t happens.
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Hand Solo
Yes, I take your points. I have learned something about met. We only reduce target sector flows when there is a 50% prob. of thunderstorm activity. Perhaps that is inadequate.
10 miles on TCAS closing at 220kts each. Thats 440kts, = over 7miles per minute, 10 miles = about 80 secs. Give us say, 3 sweeps to see that you haven't taken the turn, 15 secs. We are probably going to lose separation which means automatic suspension for us, when we have followed the rules and the crew has deviated! At the very least, it is going to be frightening. Also, TCAS gives no azimuth guidance and an attempt to interpret the cockpit screen rather than listen to an ATC avoiding turn has already led to a real nasty in France. TCAS is vertical only. If the wx is that bad won't you have seen it well before you get to it?
In the example I outlined, the first heavy deviated 2 miles to get around the wx. I don't understand how the second a/c could have missed it on the same original track.
Point 4
Yes, I take your points. I have learned something about met. We only reduce target sector flows when there is a 50% prob. of thunderstorm activity. Perhaps that is inadequate.
10 miles on TCAS closing at 220kts each. Thats 440kts, = over 7miles per minute, 10 miles = about 80 secs. Give us say, 3 sweeps to see that you haven't taken the turn, 15 secs. We are probably going to lose separation which means automatic suspension for us, when we have followed the rules and the crew has deviated! At the very least, it is going to be frightening. Also, TCAS gives no azimuth guidance and an attempt to interpret the cockpit screen rather than listen to an ATC avoiding turn has already led to a real nasty in France. TCAS is vertical only. If the wx is that bad won't you have seen it well before you get to it?
In the example I outlined, the first heavy deviated 2 miles to get around the wx. I don't understand how the second a/c could have missed it on the same original track.
Point 4
Last edited by 120.4; 1st Apr 2002 at 07:18.
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Like I said before, it's really easy in court. The Air Navigation Order states that you will not make a turn without ATC permission during weather avoidance . Its written in black and white!! And also like I said in my earlier post, its a lot easier to explain to your company management why your pax had a bumpy ride than it is to explain why you have just nearly knocked another company aircraft out of the sky! Yes, they really are that close together in the TMA around Heathrow!!
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120.4, wasn't that exactly what you were saying?
Why deviate for weather in a direction where you are sure there is other traffic, because ATC told you it is? Guess turning another way would be easier then.
Personally I think you can discuss this for ages, as it all comes down to pilots interpretation of how severe the weather is. I don't have the experience that 411A has, therefore I might be more cautious than he is.
A cumuliform cloud with tops at FL100 probably won't kill you, because it hasn't grown into full proportion yet.
As I said, traffic density and frequency congestion are factors in deciding wether to divert around it or not.
P77
Why deviate for weather in a direction where you are sure there is other traffic, because ATC told you it is? Guess turning another way would be easier then.
Personally I think you can discuss this for ages, as it all comes down to pilots interpretation of how severe the weather is. I don't have the experience that 411A has, therefore I might be more cautious than he is.
A cumuliform cloud with tops at FL100 probably won't kill you, because it hasn't grown into full proportion yet.
As I said, traffic density and frequency congestion are factors in deciding wether to divert around it or not.
P77
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If the wx is that bad won't you have seen it well before you get to it?
In the example I outlined, the first heavy deviated 2 miles to get around the wx. I don't understand how the second a/c could have missed it on the same original track.
In the example I outlined, the first heavy deviated 2 miles to get around the wx. I don't understand how the second a/c could have missed it on the same original track.
As for the second point, as has already been pointed out, there are many reasons why this could occur. Partial equipment unservicability, different mod. states, rate of movement and development of the weather, etc. etc.
Some pilots are more cautious than others. Whilst one could not condone course changes to avoid a little light fair weather cumulus, it would perhaps be sensible to avoid castigating pilots for being cautious. Furthermore, tales of "In the old days we used to fly DR through the Alps with only a hand compass and a sextant" are not helpful here.
I do not advocate pilots doing their own thing willy-nilly. First choice, every time, is to contact ATC in advance and obtain clearance for avoiding course. In extreme circumstances only, if you can't get a word in edgeways, the aircraft commander is responsible for the safety of the aircraft, its crew and passengers. He screws up, he carries the can. I'm not sure about the RTF squawk suggestion. Seems to me an abuse, but if it works I'd be prepared to try it.
Ultimately, the solution is for sensible levels of investment into equipment and manpower in ATC.
PS Pegasus - be very wary of building CB's. They can bite very hard when building. To say "It's not fully developed - it'll be fine" exhibits a misunderstanding of the dangers.
Last edited by HugMonster; 2nd Apr 2002 at 11:34.
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A sobering thought about Cu's topping out at FL100.....
Whilst I was undertaking flight training in the States a few years ago a particularly nasty tornado wreaked havoc in the Kansas area.
Although this happened hundreds of miles away, I was interested in what sort of storm would cause this sort of damage.
Having made some enquiries, you may be surprised to know that the linesquall CBs involved topped out at no more than 12500' or thereabouts. (I had some copies of doppler radar images showing the perfect "hook" shape in the middle of the returns, but lost them in a house move sadly.)
I know that the weather in the UK is different to the US, but it does make you think....
Whilst I was undertaking flight training in the States a few years ago a particularly nasty tornado wreaked havoc in the Kansas area.
Although this happened hundreds of miles away, I was interested in what sort of storm would cause this sort of damage.
Having made some enquiries, you may be surprised to know that the linesquall CBs involved topped out at no more than 12500' or thereabouts. (I had some copies of doppler radar images showing the perfect "hook" shape in the middle of the returns, but lost them in a house move sadly.)
I know that the weather in the UK is different to the US, but it does make you think....
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A few random thoughts.
I see no reason to fly through any turbulance if I can reasonably avoid it. Even a little bit can really scare the punters. But the key word here is 'reasonably'. If ATC sound maxed out, then I'm not going to request avoidance for comfort, only safety.
It would be nice if there was standard terminology, but in its absence I tend to only use the word 'request' if its a low priority (i.e. for comfort). If instead I'm concerned for safety I tend to use words like 'must' or 'need'.
e.g.
"Request left 30 for weather" (comfort)
"We need 30 left for weather" (safety)
As far as relying on TCAS to provide a indication of a safe direction to turn. No. No. Absolutely not. TCAS Traffic displays are neither designed, suitable, or certified for any other purpose than telling you roughly where to look to get a visual on the threat aircraft in the event of a TA or RA.
Nasty weather radar story. Climbing out of MAN. CBs about, plus other cloud. So WX Radar on. Pop out of cloud to see the mother in law of all CBs about 20 miles away, but nothing on radar. Turns out tilt control is knackered at certain positions and intermittently commanding full up! Don't forget you own built in broad spectrum, passive, wide angle radar receiver (i.e. the mark 1 eyeball).
CPB
I see no reason to fly through any turbulance if I can reasonably avoid it. Even a little bit can really scare the punters. But the key word here is 'reasonably'. If ATC sound maxed out, then I'm not going to request avoidance for comfort, only safety.
It would be nice if there was standard terminology, but in its absence I tend to only use the word 'request' if its a low priority (i.e. for comfort). If instead I'm concerned for safety I tend to use words like 'must' or 'need'.
e.g.
"Request left 30 for weather" (comfort)
"We need 30 left for weather" (safety)
As far as relying on TCAS to provide a indication of a safe direction to turn. No. No. Absolutely not. TCAS Traffic displays are neither designed, suitable, or certified for any other purpose than telling you roughly where to look to get a visual on the threat aircraft in the event of a TA or RA.
Nasty weather radar story. Climbing out of MAN. CBs about, plus other cloud. So WX Radar on. Pop out of cloud to see the mother in law of all CBs about 20 miles away, but nothing on radar. Turns out tilt control is knackered at certain positions and intermittently commanding full up! Don't forget you own built in broad spectrum, passive, wide angle radar receiver (i.e. the mark 1 eyeball).
CPB
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Well, I 've learned some things here about CUs. Thanks chaps.
Unfortunately, all we hear is "talk" about providing us with wx radar, but no sign of it. We never seem to get ahead of the game in this country - be it wx radar, or terminals or runways etc. It puts all of us under greater pressure.
Point 4
Unfortunately, all we hear is "talk" about providing us with wx radar, but no sign of it. We never seem to get ahead of the game in this country - be it wx radar, or terminals or runways etc. It puts all of us under greater pressure.
Point 4
