Fog and other IMC departures
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Fog and other IMC departures
Say there's a great pea souper of a fog sitting on your field and you have visibility of all of a hundred metres.
We all know you can't land at an airport if you cannot see the runway below the relevant altitude for your field.. this makes perfect sense and stops people from guessing incorrectly where the runway is and plowing into hills or buildings et cetera.
WHY THOUGH, are DEPARTURES also a no-no in this sort of weather? Say you had an airport with its own traffic radar (reasonably common among RPT airports), its own control tower (also common).. I dont see why you cannot take off.
Provided you are lined up on the runway say at the piano keys or the numbers, you know precisely what lies in front of you anyway, and though people have missed in the past it is NOT difficult to find where the sky is. Fog like that is rarely more than a few hundred feet thick - you'd climb out of it in moments and be in VMC. So.. using the traffic radar you can figure out whether there is anything in the air off the end of the runway, and grant takeoff clearances only when theres no such traffic, let the planes take off and presto, we're on our way to our destination, hindered only by the fog at the other end.... not where we took off.
Why is this not acceptable procedure?
Lasior
We all know you can't land at an airport if you cannot see the runway below the relevant altitude for your field.. this makes perfect sense and stops people from guessing incorrectly where the runway is and plowing into hills or buildings et cetera.
WHY THOUGH, are DEPARTURES also a no-no in this sort of weather? Say you had an airport with its own traffic radar (reasonably common among RPT airports), its own control tower (also common).. I dont see why you cannot take off.
Provided you are lined up on the runway say at the piano keys or the numbers, you know precisely what lies in front of you anyway, and though people have missed in the past it is NOT difficult to find where the sky is. Fog like that is rarely more than a few hundred feet thick - you'd climb out of it in moments and be in VMC. So.. using the traffic radar you can figure out whether there is anything in the air off the end of the runway, and grant takeoff clearances only when theres no such traffic, let the planes take off and presto, we're on our way to our destination, hindered only by the fog at the other end.... not where we took off.
Why is this not acceptable procedure?
Lasior
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Most RPT jets in Oz can takeoff with 300 meters runway visual range, provided the crew has had the approved training. I suppose the reason why 300meters is the limit is due to the engine failure on the take off run scenario. Sudden failure of an engine will induce some swing to the side of the runway no matter how sharp the pilot is. It is very easy to "lose" the center line in this case with such low vis. Crews are trained in the simulator to handle this sort of problem. I think that takeoffs in vis below 300meters can be made if head up displays are used that give the crew an artificial runway enviroment.
One other point, how do the fire crews find the aircraft in the fog?
One other point, how do the fire crews find the aircraft in the fog?
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Not sure if this is what you're asking, but anyway....
Sure, you can blast off as per the min requirements in Jepps / AIP, but what about your landing minima? In case of an emergency you must ensure a suitable runway is available to return to.
If that departure point is above or at minima for take off but below the landing minima, then the landing minima must be considered as the"new" take off minima. Does that make sense?
All options must be considered - and that includes the worst case scenario.
Sure, you can blast off as per the min requirements in Jepps / AIP, but what about your landing minima? In case of an emergency you must ensure a suitable runway is available to return to.
If that departure point is above or at minima for take off but below the landing minima, then the landing minima must be considered as the"new" take off minima. Does that make sense?
All options must be considered - and that includes the worst case scenario.
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Gday all,
When I learnt to fly I was made to perform 0-0 take offs in an old straight tail 182. Kept straight on the dodgy old DG and sure enough made it into the sky with out bumping into anything. I was a few years later made to do it again in a Travelair when doing my ME/CIR.
I asked why and was told, to safely perform a TKOF in dust/fog/heavy rain or any other low vis situation.
Having been trained to do it and occasionally practising in VMC saved my ass years later when I lost all vis on TKOFF and HAD to continue.
Does nobody teach this anymore?
Knowing how to operate your machine fully and properly will keep you safe when needed most.
Stickin to the published rules and regs helps too and will keep your Licence/job longer!
Cheers,
I'm gone!
When I learnt to fly I was made to perform 0-0 take offs in an old straight tail 182. Kept straight on the dodgy old DG and sure enough made it into the sky with out bumping into anything. I was a few years later made to do it again in a Travelair when doing my ME/CIR.
I asked why and was told, to safely perform a TKOF in dust/fog/heavy rain or any other low vis situation.
Having been trained to do it and occasionally practising in VMC saved my ass years later when I lost all vis on TKOFF and HAD to continue.
Does nobody teach this anymore?
Knowing how to operate your machine fully and properly will keep you safe when needed most.
Stickin to the published rules and regs helps too and will keep your Licence/job longer!
Cheers,
I'm gone!
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Lasiorhinus
The reasons for restrictions to low viz takeoffs has little to do with other traffic.
It has everything to do with aircraft and crew performance in such conditions.
Under the most limiting conditions we are allowed to go with 150M viz.
Some considerations are (but not limited to):
Visual cues at the subject airport, such as lighting and runway markings;
Performance considerations, such as turns at the runway end (special procedure/escape procedures if asymmetric);
A reliable means of ascertaining Touchdown, midpoint and/or rollout RVR or visibility;
Crosswinds;
Takeoff from less than the full length of the runway;
Reduced power/thrust takeoffs;
Who is the pilot flying;
Crew trained in low viz procedures (and current);
Availability of a suitable alternate airport within a reasonable flying time, should the unthinkable happen?;
Serviceable items such as windscreen wipers, ECU's and nosewheel steering.
Put them all together and you'll get my drift
It has everything to do with aircraft and crew performance in such conditions.
Under the most limiting conditions we are allowed to go with 150M viz.
Some considerations are (but not limited to):
Visual cues at the subject airport, such as lighting and runway markings;
Performance considerations, such as turns at the runway end (special procedure/escape procedures if asymmetric);
A reliable means of ascertaining Touchdown, midpoint and/or rollout RVR or visibility;
Crosswinds;
Takeoff from less than the full length of the runway;
Reduced power/thrust takeoffs;
Who is the pilot flying;
Crew trained in low viz procedures (and current);
Availability of a suitable alternate airport within a reasonable flying time, should the unthinkable happen?;
Serviceable items such as windscreen wipers, ECU's and nosewheel steering.
Put them all together and you'll get my drift
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I think you will find that all low vis operations in this country are actually illegal because the exemptions issued to operators are dependent upon the airport having low vis procedures in place and operating at the time of the low vis departure.
ATC do not have any promulgated low vis ops procedures and neither do the airports - these procedures are intended to stop vehicles (and aeroplanes) entering the active runway etc.
It is a technical point I know, but if anyone does come unstuck in low vis it will be interesting to see hoe the insurance companies and that that well know arm chair quarterback CASA react after the event.
I think I know what CASA will do and say - I can just about write the script for Peter Gibson - the face of the regulator and font of all knowledge!
"CASA are investigating a serious breach of the regulations by XYz AIR today after one of the airlines Boeing A402 twin engined aeroplanes suffered an engine failure of the number three engine and left the runway in high winds and fog.
CASA considers this a serious breach of the regulations and the travelling public needs to be protected from this kind reckless and dangerous behaviour.
CASA has suspended the operating licence of xyz and asked them to show cause as to why they should continue flying innocent members of the travelling public around australian skies.
The fact that no-one was injured or killed was a miracle, and the airport authorities should be congratulated for their swift action in reaching the aeroplane only 25 minutes after it crashed. The pilot "First officer Smith and his co-pilot Captain Jones have had their licences suspended pending an inquiry - it is believed that the pilot may have consumed some alcohol prior to the flight - one of the people on board the aeroplane claims to have witnessed the pilot at a restaurant the night before this serious incident occured"
The bit he would leave out is that the aircraft suffered an engine failure after injesting the airport safety operators car into the left hand engine after he entered the runway without a clearance.... and the person onboard who saw the pilot drinking 14 hours before the incident was a F/A who was seated at the same table...
Am I getting too cynical????
ATC do not have any promulgated low vis ops procedures and neither do the airports - these procedures are intended to stop vehicles (and aeroplanes) entering the active runway etc.
It is a technical point I know, but if anyone does come unstuck in low vis it will be interesting to see hoe the insurance companies and that that well know arm chair quarterback CASA react after the event.
I think I know what CASA will do and say - I can just about write the script for Peter Gibson - the face of the regulator and font of all knowledge!
"CASA are investigating a serious breach of the regulations by XYz AIR today after one of the airlines Boeing A402 twin engined aeroplanes suffered an engine failure of the number three engine and left the runway in high winds and fog.
CASA considers this a serious breach of the regulations and the travelling public needs to be protected from this kind reckless and dangerous behaviour.
CASA has suspended the operating licence of xyz and asked them to show cause as to why they should continue flying innocent members of the travelling public around australian skies.
The fact that no-one was injured or killed was a miracle, and the airport authorities should be congratulated for their swift action in reaching the aeroplane only 25 minutes after it crashed. The pilot "First officer Smith and his co-pilot Captain Jones have had their licences suspended pending an inquiry - it is believed that the pilot may have consumed some alcohol prior to the flight - one of the people on board the aeroplane claims to have witnessed the pilot at a restaurant the night before this serious incident occured"
The bit he would leave out is that the aircraft suffered an engine failure after injesting the airport safety operators car into the left hand engine after he entered the runway without a clearance.... and the person onboard who saw the pilot drinking 14 hours before the incident was a F/A who was seated at the same table...
Am I getting too cynical????
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I'm Gone!
The RAAF still teach IF take-offs "under the bag". The primary purpose is as an exercise, but I always thought it was a good idea "J.I.C."
As someone with a lot more brain cells than me once said: "take-offs are optional, landings are mandatory"
The RAAF still teach IF take-offs "under the bag". The primary purpose is as an exercise, but I always thought it was a good idea "J.I.C."
As someone with a lot more brain cells than me once said: "take-offs are optional, landings are mandatory"
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Maybe, a little cynical
Capt Laptop
Thanks for that info, I am interested to know more.
Are the low vis ops, to which you refer, a special approval below the minimums specified in AIP/Jepps. Or is it below another (Unknown) figure.
I am very curious and would like to know.
Yep it fog time around Aust. We are reguarly presented with this question for real.
The real answer for me is that it depends on the aircraft that you are flying.
A light twin (not a 20.7.1b aircraft) does not give you the garenteed climb away performance, and you MUST consider a reland. Therefore I apply the aerodrome LANDING minima as my guide for Takeoff, including any adjustments to this minima for reduced performance SE and a missed approach consideration.
A 20.7.1b aircraft does have the certificated performance and built in planning to allow climb and departure, in all but the worst emergency senarios. The AIP/Jepp published departue minimums apply, with as Jarse said ALL of the other requirments.
It is worth considering what you would do in the worst case, but that would be a full emergency and as they say, anything goes in this case, so landing under minimums is available.
Personally I don't have a problem with the reduced vis departures to the specified minimums. Its just like those old "Black Hole" NVFR or IFR Night departures, you don't see sh!t after rotate and the only way is UP.
The only way to go is to check the plates, and BRIEF thouroughly have a plan and stick to it.
LAptop, "Please explain/Expand" Thanks
Thanks for that info, I am interested to know more.
Are the low vis ops, to which you refer, a special approval below the minimums specified in AIP/Jepps. Or is it below another (Unknown) figure.
I am very curious and would like to know.
Yep it fog time around Aust. We are reguarly presented with this question for real.
The real answer for me is that it depends on the aircraft that you are flying.
A light twin (not a 20.7.1b aircraft) does not give you the garenteed climb away performance, and you MUST consider a reland. Therefore I apply the aerodrome LANDING minima as my guide for Takeoff, including any adjustments to this minima for reduced performance SE and a missed approach consideration.
A 20.7.1b aircraft does have the certificated performance and built in planning to allow climb and departure, in all but the worst emergency senarios. The AIP/Jepp published departue minimums apply, with as Jarse said ALL of the other requirments.
It is worth considering what you would do in the worst case, but that would be a full emergency and as they say, anything goes in this case, so landing under minimums is available.
Personally I don't have a problem with the reduced vis departures to the specified minimums. Its just like those old "Black Hole" NVFR or IFR Night departures, you don't see sh!t after rotate and the only way is UP.
The only way to go is to check the plates, and BRIEF thouroughly have a plan and stick to it.
LAptop, "Please explain/Expand" Thanks
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Where I work there is HIRL (with less than 60M spacing) with centreline marking. So the lowest T/O minima for multi's is
* zero ceiling and 500M vis. (800M without the lights)
This is subject to two piloted ops or single piloted turbo-jet or operative autofeather.
IFR aeroplanes below 5700KG have engine out gradient considerations.
Otherwise departure minima for all other IFR aeroplanes is
300ft ceiling and 2000M vis.
* Use IAL minima (251/1500) in case of an engine failure in multi's, and a return to land at the departure aerodrome is necessary.
Several other provisos apply re. CAO obstacle clearance etc.
Unless you are an airline type, I think the above must apply Australiaversally.
CG
* zero ceiling and 500M vis. (800M without the lights)
This is subject to two piloted ops or single piloted turbo-jet or operative autofeather.
IFR aeroplanes below 5700KG have engine out gradient considerations.
Otherwise departure minima for all other IFR aeroplanes is
300ft ceiling and 2000M vis.
* Use IAL minima (251/1500) in case of an engine failure in multi's, and a return to land at the departure aerodrome is necessary.
Several other provisos apply re. CAO obstacle clearance etc.
Unless you are an airline type, I think the above must apply Australiaversally.
CG
