A/C off the runway in CPH
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Re: A/C off the runway in CPH
Cranfield appears still to be involved
http://www.cranfieldaerospace.com/ex...e/aircraft.htm
http://www.cranfieldaerospace.com/ex...e/aircraft.htm
Re: A/C off the runway in CPH
Short Approach? I cannot see any practical alternative other than temporarily closing the runway as above. With more accurate measurements and improved landing performance calculations we might only show / proove that the runway is not long enough; thus closing it until the contamination is cleared is both practical and safe.
Meanwhile perhaps all AFM data should be marked:
”Operation on runways contaminated with water, slush, snow, ice or other contaminants implies uncertainties with regard to runway friction and contaminant drag and therefore to the achievable performance … since the actual conditions may not completely match the assumptions on which the performance information is based. Where possible, every effort should be made to ensure that the runway surface is cleared of any significant contamination.
… it is not possible to produce performance data that will precisely correlate with each specific operation on a contaminated surface".
Also all runway condition / friction reports should be prefixed with the following warning:
… there is not, at present, a common friction index for all ground friction measuring devices. Therefore it is not practicable at the present time to determine aeroplane performance on the basis of an internationally accepted friction index measured by ground friction devices.
The text above is taken from EASA / JAA NPA 14 2004 (thanks Tribo). The NPA also comments, “Notwithstanding this lack of a common index, the applicant may optionally choose to present takeoff and landing performance data as a function of a wheel braking coefficient constant with ground speed. The responsibility for relating this data to a friction index measured by a ground friction device will fall on the operator and the Operating Authority.”
Operators again have to take responsibility for safety, yet where are all of the assumptions and guidelines to be published, and what practical help will be provided for the pilots preparing for the approach and landing.
Meanwhile perhaps all AFM data should be marked:
”Operation on runways contaminated with water, slush, snow, ice or other contaminants implies uncertainties with regard to runway friction and contaminant drag and therefore to the achievable performance … since the actual conditions may not completely match the assumptions on which the performance information is based. Where possible, every effort should be made to ensure that the runway surface is cleared of any significant contamination.
… it is not possible to produce performance data that will precisely correlate with each specific operation on a contaminated surface".
Also all runway condition / friction reports should be prefixed with the following warning:
… there is not, at present, a common friction index for all ground friction measuring devices. Therefore it is not practicable at the present time to determine aeroplane performance on the basis of an internationally accepted friction index measured by ground friction devices.
The text above is taken from EASA / JAA NPA 14 2004 (thanks Tribo). The NPA also comments, “Notwithstanding this lack of a common index, the applicant may optionally choose to present takeoff and landing performance data as a function of a wheel braking coefficient constant with ground speed. The responsibility for relating this data to a friction index measured by a ground friction device will fall on the operator and the Operating Authority.”
Operators again have to take responsibility for safety, yet where are all of the assumptions and guidelines to be published, and what practical help will be provided for the pilots preparing for the approach and landing.
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Re:Augmenting the braking by use of Backstick
http://www.pprune.org/forums/showthr...201568&page=13
Belgique's post on this SWA thread (above) addresses the very significant effect that progressive backstick can have upon increasing the wheel-braking coefficient and minimising anti-skid wheel release (for spin-up on contaminated runways).
From what I've read on this thread, no-one seems to have trialled this or factored it into the stopping trial. That seems to be quite an oversight IMHO.
Despite what the nay-sayers have said on that SWA thread (with some really crazy logic such as holding the stick forward to stop the nose rising and to achieve most effective braking), it has always been an effective braking augmentation technique. Used properly it would have probably stopped 50% of airplanes going off the end.
Once in reverse and with auto-braking applied, how could the nose possibly rise? Think of the distribution of weight BEFORE reverse or braking commences. Think spoiler effect. Then think of the strong nose-down pitching effect of both reverse and braking.
Then attempt to argue logically against backstick being an effective measure to increase the weight upon wheels. That would be an interesting argument to see and dissect.
Belgique's post on this SWA thread (above) addresses the very significant effect that progressive backstick can have upon increasing the wheel-braking coefficient and minimising anti-skid wheel release (for spin-up on contaminated runways).
From what I've read on this thread, no-one seems to have trialled this or factored it into the stopping trial. That seems to be quite an oversight IMHO.
Despite what the nay-sayers have said on that SWA thread (with some really crazy logic such as holding the stick forward to stop the nose rising and to achieve most effective braking), it has always been an effective braking augmentation technique. Used properly it would have probably stopped 50% of airplanes going off the end.
Once in reverse and with auto-braking applied, how could the nose possibly rise? Think of the distribution of weight BEFORE reverse or braking commences. Think spoiler effect. Then think of the strong nose-down pitching effect of both reverse and braking.
Then attempt to argue logically against backstick being an effective measure to increase the weight upon wheels. That would be an interesting argument to see and dissect.
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Re: A/C off the runway in CPH
TheOddOne,
Sorry, my bad! Obviously, I trust you guys to give us the correct runway state - and will of course happily accept a WETx3 runway. In that case no need to get the FC, since WET is a well-defined case performance-wise.
But I still find it hard to accept that ATC will not give me an FC for a contaminated runway. It just cannot be right that a crew must accept to act as guniea-pigs for everybody else in the stack (as ShortApproach? described it). My point is - yes, there is no way to scientifically link a measured FC with that experienced by an aircraft. But at the same time - when you pass us an FC, it leaves us FC in an unambigous position legally speaking. The manufacturer has supplied data that determines the aircrafts' stop cabability as a function of FC. If we recieve an unambigous FC from you guys, based on an unambigous reading by e.g. an SFT - then there is no doubt, an overrun (or other incident) can only be tributed to 1) Flight crew not following established procedures 2) Wrong interpretation of data (e.g. misreading tables) 3) Wrong transmission of data from ATC to A/C 4) Manufacturers performance data are incorrect 5) Systematic errors in the measuring equipment 6) Operator has applied the data in the wrong manner.
I therefore feel that the responsibility for determining the relationship between the FC (as measured by a given piece of test equipment) and the stop cabability of the A/C lies with the manufacturer (and the operator who applies the data) - end of story. They make the thing, they test it, they supply the data, we operate it.
There will of course still be cases, e.g. wet snow or wildly varying results from multiple runs - where the FC must be reported as "unreliable", and in those cases we must make up our minds if we want to divert or act as/wait for a guniea-pig. But withholding information from flightcrew - for what appears as legal concerns - I find less than impressive. If all scandi airports adopted that blanket policy, that corner of Europe would shut down for 4-6 months a year!
I wonder if an FODCOM has been issued to describe this new UK ATC policy? This forum was the first I heard of it (yep, I know, that's kind of sad - need to get out more
) - it seems very harsh that just because an airport gives e.g. 1019 3000 -SN BKN007 - that airport could theoretically not be able to keep the runway to WET x 3 status, deposits might still exist - and therefore, I must consider it below planning minima! 
only because ATC is not allowed to pass the FC... 
Then again - prolly a 'very British thing' to do
Empty
Sorry, my bad! Obviously, I trust you guys to give us the correct runway state - and will of course happily accept a WETx3 runway. In that case no need to get the FC, since WET is a well-defined case performance-wise.
But I still find it hard to accept that ATC will not give me an FC for a contaminated runway. It just cannot be right that a crew must accept to act as guniea-pigs for everybody else in the stack (as ShortApproach? described it). My point is - yes, there is no way to scientifically link a measured FC with that experienced by an aircraft. But at the same time - when you pass us an FC, it leaves us FC in an unambigous position legally speaking. The manufacturer has supplied data that determines the aircrafts' stop cabability as a function of FC. If we recieve an unambigous FC from you guys, based on an unambigous reading by e.g. an SFT - then there is no doubt, an overrun (or other incident) can only be tributed to 1) Flight crew not following established procedures 2) Wrong interpretation of data (e.g. misreading tables) 3) Wrong transmission of data from ATC to A/C 4) Manufacturers performance data are incorrect 5) Systematic errors in the measuring equipment 6) Operator has applied the data in the wrong manner.
I therefore feel that the responsibility for determining the relationship between the FC (as measured by a given piece of test equipment) and the stop cabability of the A/C lies with the manufacturer (and the operator who applies the data) - end of story. They make the thing, they test it, they supply the data, we operate it.
There will of course still be cases, e.g. wet snow or wildly varying results from multiple runs - where the FC must be reported as "unreliable", and in those cases we must make up our minds if we want to divert or act as/wait for a guniea-pig. But withholding information from flightcrew - for what appears as legal concerns - I find less than impressive. If all scandi airports adopted that blanket policy, that corner of Europe would shut down for 4-6 months a year!
I wonder if an FODCOM has been issued to describe this new UK ATC policy? This forum was the first I heard of it (yep, I know, that's kind of sad - need to get out more
) - it seems very harsh that just because an airport gives e.g. 1019 3000 -SN BKN007 - that airport could theoretically not be able to keep the runway to WET x 3 status, deposits might still exist - and therefore, I must consider it below planning minima! only because ATC is not allowed to pass the FC... Then again - prolly a 'very British thing' to do
Empty
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Re: A/C off the runway in CPH
Empty,
I spent many years both as an operative at Heathrow and a manager at LGW giving out readings down to 0.25 when we used a MuMeter and these were used by crews. In one case, back in the early eighties, a BA Tristar landed in the early hours at LHR in such conditions, turning off the runway was asked for braking action assessment by ATC, said
'Don't know, you said it was slippery, so we didn't use the brakes, just reverse!'
That's the luxury of a 4,000M runway, of course.
We were all familiar with the icy tables and what crews could and wouldn't accept.
What we really need is some serious back pressure from industry to say that we CAN operate safely in reduced braking action and limited contamination conditions, we need to work out what those conditions are, get on with it so that we can get on with our operation.
We're lucky at LGW where 'back to black' and 'Wet Wet Wet' are usually achievable. I hope this Winter doesn't prove me wrong!
Cheers,
The Odd One
I spent many years both as an operative at Heathrow and a manager at LGW giving out readings down to 0.25 when we used a MuMeter and these were used by crews. In one case, back in the early eighties, a BA Tristar landed in the early hours at LHR in such conditions, turning off the runway was asked for braking action assessment by ATC, said
'Don't know, you said it was slippery, so we didn't use the brakes, just reverse!'
That's the luxury of a 4,000M runway, of course.
We were all familiar with the icy tables and what crews could and wouldn't accept.
What we really need is some serious back pressure from industry to say that we CAN operate safely in reduced braking action and limited contamination conditions, we need to work out what those conditions are, get on with it so that we can get on with our operation.
We're lucky at LGW where 'back to black' and 'Wet Wet Wet' are usually achievable. I hope this Winter doesn't prove me wrong!
Cheers,
The Odd One
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Re: A/C off the runway in CPH
TheOddOne,
Yep - 4000 m. is always welcome under such conditions
Up further north such luxury is hard to come by, so number-crunching suddenly becomes a good way to avoid appearing before the magistrates'...
You are right - we need ICAO & IATA in on this one, and get some guidelines laid down. But even if that process started today, it would be 5-7 years before the paperwork would be in place. In the meantime, we need to get by with all the info we go - in order to operate safely. So - would very much like to know where I can find info about the new policy (about not passing FCs) - because I really would like our FSO to get on the case & start asking NATS some questions. If you - or anybody else - could help in this regard, I'd appreciate it very much
Brgds fm
Empty
Yep - 4000 m. is always welcome under such conditions
Up further north such luxury is hard to come by, so number-crunching suddenly becomes a good way to avoid appearing before the magistrates'...You are right - we need ICAO & IATA in on this one, and get some guidelines laid down. But even if that process started today, it would be 5-7 years before the paperwork would be in place. In the meantime, we need to get by with all the info we go - in order to operate safely. So - would very much like to know where I can find info about the new policy (about not passing FCs) - because I really would like our FSO to get on the case & start asking NATS some questions. If you - or anybody else - could help in this regard, I'd appreciate it very much
Brgds fm
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Re: A/C off the runway in CPH
Originally Posted by Empty Cruise
TheOddOne,
I wonder if an FODCOM has been issued to describe this new UK ATC policy?
I wonder if an FODCOM has been issued to describe this new UK ATC policy?
FODCOM 17/2001
FODCOM 23/2003
ATSIN Number 37 Issued 11 November 2003
AIC 61/1999
UK AIP AD 1.2.2
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Re: A/C off the runway in CPH
Thanks, tribo! Only started flying with a UK operator in 2005, so have missed those ones - will look them up
Empty
Empty
Re: A/C off the runway in CPH
OVERTALK Having been involved with a few military and civilian aircraft trials relating to aerodynamic (nose up/back stick) landings, the answer to your proposition remains as given in the other threads; it is to follow the manufacturers procedures.
Do pilots really think that they have discovered something new in aerodynamic breaking which manufacturers have not considered? If there were better techniques, then we would all be using them in our over competitive industry. The core of many manufacturers’ advice is to concentrate on the important and most effective means of stopping the aircraft, particularly by using maximum braking with all wheels firmly on the ground. Just because the aircraft is on the ground does not mean that the controls are ineffective and will not change the load distribution, you can lift the nose in many aircraft types even against brakes and reverse. The HS 125 for example can be steered on the runway with aileron even though full lift dump is deployed.
Some naval aircraft, which for obvious reasons may not have had the best brakes, were allowed to use aerodynamic braking for land based operations. However, there were many pilots who misjudged the runway length such that when the nose was lowered / effective braking applied, insufficient runway remained. These pilots would have been better placed to use full brake, even with the risks of brake fade or overheating, which would have required a tow off the runway; that situation would have been better than a tow out of the mud.
Similarly, my limited trials experience in landing on snow confirmed that the ‘keep it simple / back to basics’ advice for stopping was the most effective. Get the aircraft on the ground, right place, and right speed, lower the nose, and use max brake. The aircraft would stop ‘when it was going to stop’. The ground roll landing distances were measured very accurately in the fresh snow.
For trials reasons the conditions were at the limit or in excess of any runway condition approved commercial operations; be assured that neither I nor anyone else has need of any more experience of sliding uncontrollable down the runway hoping that it was long enough. Furthermore, if the cross wind had exceeded 5 kts I doubt that the aircraft would have remained on the runway, as both rudder and steering were ineffective.
Empty Cruise Re your comment “… since WET is a well-defined case performance-wise.”
I think that if you study the DoT Canada reference, you will find that wet is not as well defined as might be thought and in some cases has similar risks to operations on a contaminated runway, and that is before you think of aquaplaning or wet/flooded conditions.
Do pilots really think that they have discovered something new in aerodynamic breaking which manufacturers have not considered? If there were better techniques, then we would all be using them in our over competitive industry. The core of many manufacturers’ advice is to concentrate on the important and most effective means of stopping the aircraft, particularly by using maximum braking with all wheels firmly on the ground. Just because the aircraft is on the ground does not mean that the controls are ineffective and will not change the load distribution, you can lift the nose in many aircraft types even against brakes and reverse. The HS 125 for example can be steered on the runway with aileron even though full lift dump is deployed.
Some naval aircraft, which for obvious reasons may not have had the best brakes, were allowed to use aerodynamic braking for land based operations. However, there were many pilots who misjudged the runway length such that when the nose was lowered / effective braking applied, insufficient runway remained. These pilots would have been better placed to use full brake, even with the risks of brake fade or overheating, which would have required a tow off the runway; that situation would have been better than a tow out of the mud.
Similarly, my limited trials experience in landing on snow confirmed that the ‘keep it simple / back to basics’ advice for stopping was the most effective. Get the aircraft on the ground, right place, and right speed, lower the nose, and use max brake. The aircraft would stop ‘when it was going to stop’. The ground roll landing distances were measured very accurately in the fresh snow.
For trials reasons the conditions were at the limit or in excess of any runway condition approved commercial operations; be assured that neither I nor anyone else has need of any more experience of sliding uncontrollable down the runway hoping that it was long enough. Furthermore, if the cross wind had exceeded 5 kts I doubt that the aircraft would have remained on the runway, as both rudder and steering were ineffective.
Empty Cruise Re your comment “… since WET is a well-defined case performance-wise.”
I think that if you study the DoT Canada reference, you will find that wet is not as well defined as might be thought and in some cases has similar risks to operations on a contaminated runway, and that is before you think of aquaplaning or wet/flooded conditions.
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Re: A/C off the runway in CPH
Originally Posted by Empty Cruise
TheOddOne,
I therefore feel that the responsibility for determining the relationship between the FC (as measured by a given piece of test equipment) and the stop cabability of the A/C lies with the manufacturer (and the operator who applies the data) - end of story. They make the thing, they test it, they supply the data, we operate it.
I therefore feel that the responsibility for determining the relationship between the FC (as measured by a given piece of test equipment) and the stop cabability of the A/C lies with the manufacturer (and the operator who applies the data) - end of story. They make the thing, they test it, they supply the data, we operate it.
Question:
Does Boeing hava a position on how to relate runway friction chart information to reported braking action?
Response:
There are many different runway friction vehicles, which have not been calibrated to a standard measurement system nor the airplane. At this point Boeing does not correlate runway friction measurements to pilot reported braking actions or airplane braking coefficient.
Question:
Then how does (is) flight operations (to) determine what to use?
Response:
The slippery runway (landing and takeoff) data provided by Boeing is a function of airplane braking coefficient. Airplane braking coefficient is the percentage of the airplane's weight on the wheels (W-L) which is converted into an effective stopping force. For example, for a reported airplane braking coefficient of 0.20, an airplane with a (W-L) of 100,000 lbs would create 20,000 lbs of stopping force.
Boeing provides slippery runway data based on an airplane braking coefficient of 0.05 to 0.2 (Poor to Good reported braking action). Please review the following guidance for relating commonly used terms of reporting runway condition to airplane braking coefficient:
Followed by a table with headings:
- Airplane Braking Coefficient
- Pilot Reported Braking Action
- Runway Description
And content:
- 0.4
- Approximates dry runway
- Friction limited certification values
- 0.2
- Good
- Wet Runway, Jar certification for compact snow
- 0.1
- Medium/Fair
- Ice, Compacted Snow
- 0.05
- Poor/Nil
- Wet Ice, Slush, Melting Compacted Snow, Standing Water
On a runway covered with wet ice, slush, melting compacted snow, or standing water the possibility of hydroplasning exists, which can result in nil braking capability. For that reason we recommend that the flight crew use the operational landing distance for POOR Braking Action in such conditions to determine the acceptability of landing on such a runway.
Airbus "feel"
Getting to grips with cold weather operations
http://www.wingfiles.com/
CORRELATION BETWEEN REPORTED MY AND BRAKING PERFORMANCEPlease bear in mind:
- Airports release a friction coefficient derived from a measuring vehicle. This friction coefficient is termed as "reported MY".
The actual friction coefficient termed as the "Effective MY" is the result of the interaction tire/runway and depends on the tire pressure, tire wear, aircraft speed, aircraft weight and anti-skid system efficiency.
To date, there is no way to establish a clear correlation between the "reported MY" and the "effective MY". There is even a poor correlation between the "reported MY" of the different measuring vehicles.
It is the very difficult to link the published performance on a contaminated runway to a "reported MY" only.
- The presence of fluid contaminants (water, slush and loose snow) on the runway surface reduces the friction coefficient, may lead to aquaplaning (also called hydroplaning) and creates an additional drag.
This additional drag is due to the precipitation of the contaminant onto the landing gear and the airframe, and to the displacement of the fluid from the path of the tire. Consequently, braking and accelerating performance are affected. The impact on the accelerating forces leads to a limitation in depth of the contaminant for takeoff.
Hard contaminants (Compacted snow and ice) only affect the braking performance of the aircraft by a reduction of the friction coefficient.
- Airbus Industrie publishes the takeoff and landing performance according to the type of the contaminant, and to the depth of fluid contaminants.
EASA "feel":
From NPA 14/2004 Operations on contaminated runways
http://www.easa.eu.int/doc/Rulemakin...PA_14_2004.pdf
7.3.3
Use of Ground Friction Measurement Devices
Ideally it would be preferable to relate aeroplane braking performance to a friction index measured by a ground friction device that would be reported as part of a Surface Condition Report. However, there is not, at present, a common friction index for all ground friction measuring devices. Hence it is not practicable at the present time to determine aeroplane performance on the basis of an internationally accepted friction index measured by ground friction devices. Notwithstanding this lack of a common index, the applicant may optionally choose to present take-off and landing performance data as a function of an aeroplane braking coefficient or wheel braking coefficient constant with ground speed. The responsibility for relating this data to a friction index measured by a ground friction device will fall on the operator and the operating authority.
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Re: A/C off the runway in CPH
Alf & Tribo,
Thanks, v. good info.
When you sit in the aircraft - with the OM part C in hand - this manual has been promulgated by our operator and approved by the CAA.
Therefore, as long as I follow that manual - and once & again add a bit extra "common sense"-margin - I am legally speaking "off the hook". I know that there might be a protracted legal battle should something still go wrong - but the crew will come out clean.
I know that - even with the FC available - there will be cases where, even though the data available indicates that a landing is feasible, we will decide against trying. But that is a safety matter - before we get to that bridge, we need to sort out the matter of legality.
So - any thoughts on the legality aspect as seen from ATCO and FD crews' side? If we have the approved Part C and get a "reliable" FC from ATC - are we legal or not? That is quite an important question - and if the answer is not clear, we can tear out every 3rd page in the perf.manual
Thanks for the good input - Empty
Thanks, v. good info.
When you sit in the aircraft - with the OM part C in hand - this manual has been promulgated by our operator and approved by the CAA.
Therefore, as long as I follow that manual - and once & again add a bit extra "common sense"-margin - I am legally speaking "off the hook". I know that there might be a protracted legal battle should something still go wrong - but the crew will come out clean.
I know that - even with the FC available - there will be cases where, even though the data available indicates that a landing is feasible, we will decide against trying. But that is a safety matter - before we get to that bridge, we need to sort out the matter of legality.
So - any thoughts on the legality aspect as seen from ATCO and FD crews' side? If we have the approved Part C and get a "reliable" FC from ATC - are we legal or not? That is quite an important question - and if the answer is not clear, we can tear out every 3rd page in the perf.manual
Thanks for the good input - Empty
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Re: A/C off the runway in CPH
Overtalk.
The technique you describe has been responsible for a runway overrun.
Backstick lead to a positive angle of attack, which reduced the pressure on the mainwheels due to lift from the wing and in turn the braking effectiveness was reduced.
Follow the Flying manual advice!
The technique you describe has been responsible for a runway overrun.
Backstick lead to a positive angle of attack, which reduced the pressure on the mainwheels due to lift from the wing and in turn the braking effectiveness was reduced.
Follow the Flying manual advice!
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Re: A/C off the runway in CPH
Originally Posted by Empty Cruise
So - any thoughts on the legality aspect as seen from ATCO and FD crews' side? If we have the approved Part C and get a "reliable" FC from ATC - are we legal or not? That is quite an important question - and if the answer is not clear, we can tear out every 3rd page in the perf.manual
The person on the ground are the one who "feel the stuff" and evaluate the condition at the movement area and the output from the (friction) measuring devices and report it to the ATC according to, by the State, regulated/approved format for further transmitting to the end user (operator/pilot).
(These formats do, unfortunately, vary from State to State)
The person on the ground take the desicion when to close the runway or any other part of the movement area for maintenance, preparation, etc and when to open for traffic by issuing a Surface Condition Report
Re: A/C off the runway in CPH
Empty Cruise “…are we legal or not?”
Just because the book states that something can be done, or that the Authority has approved the book, does not imply that operations on contaminated runways are lawyer proof or indeed sensible at ant time.
The Captain has the responsibility, a duty of care for the passengers, which is exercised through judgment and decisions. If there is an accident, most lawyers will walk all over the crew to get to the money – to the operator and the insurance. There is little that the crew can do to protect themselves except do what is right in the situation presented to them – but first make sure that the situation is understood. ‘What is right’ means avoiding accident prone circumstances and unnecessary risk, and by taking precautions to safeguard the aircraft and passengers.
When considering operations on contaminated runways, this means having knowledge of all advisory information, i.e. UK CAA AICs, FODCOMs, and JAR-OPS ACJs, etc, then with due judgment of this and all other information ‘in the book’, SNOWTAM, ATIS, the crew has to decide on the best (safest) course of action. There should be good guidance in the Ops Manual, if not then the best place to consider the decision is on the ground before any pressures of in-flight situations are encountered, as these are often associated with time/fuel and commercial issues that might bias judgment.
The crew need to understand the limitations of book data and runway condition reports, and the reduced safety margins these items provided; this should enable crews to determine a baseline standard for a safe operation. Then in-flight, the crew can apply judgment as to any detrimental effect of the actual circumstances such as cross wind, runway surface, concrete/tarmac, grooved/smooth, length available, landing weight as a % of max allowed (how close to the limit is this landing), and most important consider how each individual might have been biased in their judgment. Individuals need self discipline in their thinking, a need to cross check both information and understanding, and to question everything; these are central areas of airmanship. Then and only then have you the basis of a defense, legally or morally whichever applies.
The question to ask is not if the operation is legal, or if the crew will come out clean (which I doubt), it is whether each individual is satisfied with his or her performance. For advice of how to achieve that I refer to the following from Tony Hayes, CFI Brisbane Valley Leisure Aviation Centre.
”Airmanship is a personal attitude to flying, why we do it, how we do it. Airmanship must grow with training, experience, and personal exposure. It is not just about staying alive or not bending the airplane or yourself, it is about walking off the airfield knowing that you have both performed and crafted an activity. You have been totally aware of what you have done and why you enjoyed it, and at that point you owe nothing to anyone”.
Just because the book states that something can be done, or that the Authority has approved the book, does not imply that operations on contaminated runways are lawyer proof or indeed sensible at ant time.
The Captain has the responsibility, a duty of care for the passengers, which is exercised through judgment and decisions. If there is an accident, most lawyers will walk all over the crew to get to the money – to the operator and the insurance. There is little that the crew can do to protect themselves except do what is right in the situation presented to them – but first make sure that the situation is understood. ‘What is right’ means avoiding accident prone circumstances and unnecessary risk, and by taking precautions to safeguard the aircraft and passengers.
When considering operations on contaminated runways, this means having knowledge of all advisory information, i.e. UK CAA AICs, FODCOMs, and JAR-OPS ACJs, etc, then with due judgment of this and all other information ‘in the book’, SNOWTAM, ATIS, the crew has to decide on the best (safest) course of action. There should be good guidance in the Ops Manual, if not then the best place to consider the decision is on the ground before any pressures of in-flight situations are encountered, as these are often associated with time/fuel and commercial issues that might bias judgment.
The crew need to understand the limitations of book data and runway condition reports, and the reduced safety margins these items provided; this should enable crews to determine a baseline standard for a safe operation. Then in-flight, the crew can apply judgment as to any detrimental effect of the actual circumstances such as cross wind, runway surface, concrete/tarmac, grooved/smooth, length available, landing weight as a % of max allowed (how close to the limit is this landing), and most important consider how each individual might have been biased in their judgment. Individuals need self discipline in their thinking, a need to cross check both information and understanding, and to question everything; these are central areas of airmanship. Then and only then have you the basis of a defense, legally or morally whichever applies.
The question to ask is not if the operation is legal, or if the crew will come out clean (which I doubt), it is whether each individual is satisfied with his or her performance. For advice of how to achieve that I refer to the following from Tony Hayes, CFI Brisbane Valley Leisure Aviation Centre.
”Airmanship is a personal attitude to flying, why we do it, how we do it. Airmanship must grow with training, experience, and personal exposure. It is not just about staying alive or not bending the airplane or yourself, it is about walking off the airfield knowing that you have both performed and crafted an activity. You have been totally aware of what you have done and why you enjoyed it, and at that point you owe nothing to anyone”.
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Re: A/C off the runway in CPH
Originally Posted by tribo
The person on the ground take the desicion when to close the runway or any other part of the movement area for maintenance, preparation, etc and when to open for traffic by issuing a Surface Condition Report
Neither I (ATCO) or the ground guy whoo does the measuring will take steps to close a runway. He reports what he sees and measuers, I relay the report to the A/C´s, and then it´s ultimately their decision.
Someone is always willing to be the guiney... I guess it´s the same mechanism that will sometimes drive me to tweak the rules just to make the weels go round. Eventhough I can be certain to have my b**** chopped of, if something goes wrong.
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Re: A/C off the runway in CPH
Originally Posted by Short Approach?
Neither I (ATCO) or the ground guy whoo does the measuring will take steps to close a runway. He reports what he sees and measuers, I relay the report to the A/C´s, and then it´s ultimately their decision.
http://www.airports.unina.it/
They have a Working Paper 061 Aspects related to winter mintenance of aerodromes, hereunder contamination measurement and reporting.
http://www.airports.unina.it/WP%20061%20.pdf
With four appendix:
http://www.airports.unina.it/WP%2006...pendix%201.pdf
http://www.airports.unina.it/WP%2006...pendix%202.pdf
http://www.airports.unina.it/WP%2006...pendix%203.pdf
http://www.airports.unina.it/WP%2006...pendix%204.pdf
There exist a draft GASR Working Paper, (not publihed) from where i quote:
Introduction
Winter operations are among the most challenging flight operations. During winter the weather is worse, with low cloud base, reduced visibility and heavy winds, and in addition the runways often are covered with snow and ice.
The GASR AGA WP061 – “Aspects related to winter maintenance of aerodromes, hereunder contamination measurement and reporting”- stated that predicting aircraft braking action based on friction measurement is more complicated and unreliable than earlier assumed. Further it was realised that the way of reporting runway status to aircrew varies among GASR states.
During the winter 1999/2000 Norway experienced a number of runway veer-offs/overruns on contaminated runways. Thereafter the CAA-Norway focused on winter operations and one result was the new requirements for runway status reporting. The revised reporting gives special attention to the great uncertainty related to the measurement of friction level and depth of deposits.
However it is of vital importance for safe winter operations that reporting of runway status can never be a substitute to the removal of deposits of slush, snow or ice. Aviation authorities should therefore require that the aerodrome operator establish exact criteria for winter maintenance of runways and other parts of the movement area and to deny operations on areas not meeting the established criteria. The requirements for a safety management system should further assure that if a risk analyses concludes that the runway conditions are not acceptable, then the runway should be kept closed until the conditions becomes acceptable.
In the Norwegian regulation BSL E 4-1 and 4-2 the Authorithy requires closing criterias to be established. (Norwegian text)
http://www.lovdata.no/cgi-wift/ldles...0627-0935.html
http://www.lovdata.no/cgi-wift/ldles...0427-0670.html
Last edited by tribo; 3rd Jan 2006 at 21:35.
ECON cruise, LR cruise...
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Re: A/C off the runway in CPH
alf5071h,
While I agree on the definition of airmanship, being denied part of the data (the FC) does not exactly help in exercising that airmanship. Wouldn't it be much safer - airmanship-wise - to give the crew the FC (where available) and then let them decide for themselves?
Secondly, even the best airmanship only covers up to a 99,9% CEP - we all need to know where we stand when the last 0,1% strikes. 100% CEP is only achievable if you leave the aircraft on the ground & go home
If I'm told that FC is unreliable - and no pilot reports exist - we're out of there, end of story. My concern is the pure legality of using the existing aeroplane data, as processed & promulgated by my operator, based on unambigous FC values transmitted by ATC. These conditions are encountered by pilots all over the world every year - and we're all able to operate safely under these conditions.
So - leaving the airmanship aside (I doubt anybody here wants to disagree with any of the above posts on the airmanship issue) - we return to the legality aspect of things. If the operators maintain that their data is only advisory & that the use of this data is responsibility of the operator, and we use the data as issued by our operator - where do we stand legally?
Empty
Originally Posted by alf5071h
The question to ask is not if the operation is legal, or if the crew will come out clean (which I doubt), it is whether each individual is satisfied with his or her performance.
Secondly, even the best airmanship only covers up to a 99,9% CEP - we all need to know where we stand when the last 0,1% strikes. 100% CEP is only achievable if you leave the aircraft on the ground & go home
If I'm told that FC is unreliable - and no pilot reports exist - we're out of there, end of story. My concern is the pure legality of using the existing aeroplane data, as processed & promulgated by my operator, based on unambigous FC values transmitted by ATC. These conditions are encountered by pilots all over the world every year - and we're all able to operate safely under these conditions.
So - leaving the airmanship aside (I doubt anybody here wants to disagree with any of the above posts on the airmanship issue) - we return to the legality aspect of things. If the operators maintain that their data is only advisory & that the use of this data is responsibility of the operator, and we use the data as issued by our operator - where do we stand legally?
Empty
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The Effectiveness of Braking with Progressive Backstick
ALF5071H said (Overtalk comments interspersed in blue)
OVERTALK Having been involved with a few military and civilian aircraft trials relating to aerodynamic (nose up/back stick) landings, the answer to your proposition remains as given in the other threads; it is to follow the manufacturers procedures. Hasn't anything whatsoever to do with aerodynamic braking (note spelling of "braking"). In fact it's quite silly to attempt to equate aerodynamic braking with what's being suggested. What's being advocated is a progressive and tempered introduction of backstick once nosewheel is on, spoilers are deployed, reverse is selected and braking has commenced. Note that all three of those traditional retardation measures cause a strong nose down pitching moment. Trying to pretend otherwise is very "imaginative" - unless your a/c sports a tailwheel...... so the nose will NOT rise. Even without those three cumulative nose-down pitching moments, a normal CofG distribution will accord a nose-down moment.
Do pilots really think that they have discovered something new in aerodynamic breaking[sic] which manufacturers have not considered? If there were better techniques, then we would all be using them in our over competitive industry. The core of many manufacturers’ advice is to concentrate on the important and most effective means of stopping the aircraft, particularly by using maximum braking with all wheels firmly on the ground.The advocated technique is merely a means of very quickly getting maximum weight upon wheels (or as you say, all wheels firmly on the ground - aka traction). This minimizes the intervention of anti-skid, which makes braking less effective the more it has to cut in to maintain wheel rotation. Remember that it's stopping the wheel that blows the tyre. Two ways of NOT stopping the wheel = antiskid (decreases braking effectiveness) and utilizing UP elevator to push the maingear into the pavement. Just because the aircraft is on the ground does not mean that the controls are ineffective and will not change the load distribution, you can lift the nose in many aircraft types even against brakes and reverse. The HS 125 for example can be steered on the runway with aileron even though full lift dump is deployed.
Some naval aircraft, which for obvious reasons may not have had the best brakes, were allowed to use aerodynamic braking for land based operations. However, there were many pilots who misjudged the runway length such that when the nose was lowered / effective braking applied, insufficient runway remained. These pilots would have been better placed to use full brake, even with the risks of brake fade or overheating, which would have required a tow off the runway; that situation would have been better than a tow out of the mud. Some very muddy and irrelevant thinking here. Best to stick with aerodynamics rather than anecdotal bombast and bluster...
Similarly, my limited trials experience in landing on snow confirmed that the ‘keep it simple / back to basics’ advice for stopping was the most effective. Get the aircraft on the ground, right place, and right speed, lower the nose, and use max brake.Couldn't agree more. However most overruns are caused by pilots making human errors, perhaps due to illusion, perhaps fatigue, possibly indecision. The recommended "introduced backstick" technique may have made all the difference at Toronto and Midway. I reiterate that it is merely a very effective method of adding main-wheel traction on contaminated runways for increased braking effectiveness - and one that has been widely overlooked and apparently, is only being used by a competent few. When you are surrounded by variables and indeterminants such as unreliable and optimistic braking action reports, downdrafts, skittish tailwinds and mu-meter readings, it is always nice to have a big trick up your sleeve. Those that don't will always be the ones that make the headlines and have to go find another career. Blindly believing that the manufacturer knows all and tells all is for blind men. The aircraft would stop ‘when it was going to stop’. The ground roll landing distances were measured very accurately in the fresh snow.
For trials reasons the conditions were at the limit or in excess of any runway condition approved commercial operations; be assured that neither I nor anyone else has need of any more experience of sliding uncontrollable down the runway hoping that it was long enough. Furthermore, if the cross wind had exceeded 5 kts I doubt that the aircraft would have remained on the runway, as both rudder and steering were ineffective.
For trials reasons the conditions were at the limit or in excess of any runway condition approved commercial operations; be assured that neither I nor anyone else has need of any more experience of sliding uncontrollable down the runway hoping that it was long enough. Furthermore, if the cross wind had exceeded 5 kts I doubt that the aircraft would have remained on the runway, as both rudder and steering were ineffective.
Re: A/C off the runway in CPH
Empty Cruise “… where do we stand legally?"
Not being legally qualified I cannot say, but having been on the correct side of the dock in the aftermath of an accident, I can only share my opinion as above.
Again, from my experience, lawyers only offer advice.
If all data is advisory the debate might be whether the pilot is the best person to make the judgment, and then probably not to make that judgment in the air.
Current contaminated runway operations involve a higher level of risk than that accepted in normal operations. The regulatory authorities appear to accept this, although there is evidence that not all of them understand the risks (see Tribo’s posts). The advice that would assist pilots in making their judgment in those situations that change the basic risk assumed by the authority and ops manual, appear to be weakly presented and poorly disseminated.
Some of the best advice that I have seen is in AIC 61-99 “Operations from contaminated runways, by all classes of aeroplane, should be avoided whenever possible”.
If your lawyer gave you that advice, what would your decision be?
“These conditions are encountered by pilots all over the world every year - and we're all able to operate safely under these conditions”.
This is a misnomer; accident statistics show that overruns now contribute a high proportion of hull losses or major damage (not fatalities) and are of growing concern to the industry (and insurers).
A safe operation is a relative term; you are safe until you have an accident. In addition, public perception (heightened awareness in the press) often determines ‘safety’.
Remember that members of the public form the jury.
Not being legally qualified I cannot say, but having been on the correct side of the dock in the aftermath of an accident, I can only share my opinion as above.
Again, from my experience, lawyers only offer advice.
If all data is advisory the debate might be whether the pilot is the best person to make the judgment, and then probably not to make that judgment in the air.
Current contaminated runway operations involve a higher level of risk than that accepted in normal operations. The regulatory authorities appear to accept this, although there is evidence that not all of them understand the risks (see Tribo’s posts). The advice that would assist pilots in making their judgment in those situations that change the basic risk assumed by the authority and ops manual, appear to be weakly presented and poorly disseminated.
Some of the best advice that I have seen is in AIC 61-99 “Operations from contaminated runways, by all classes of aeroplane, should be avoided whenever possible”.
If your lawyer gave you that advice, what would your decision be?
“These conditions are encountered by pilots all over the world every year - and we're all able to operate safely under these conditions”.
This is a misnomer; accident statistics show that overruns now contribute a high proportion of hull losses or major damage (not fatalities) and are of growing concern to the industry (and insurers).
A safe operation is a relative term; you are safe until you have an accident. In addition, public perception (heightened awareness in the press) often determines ‘safety’.
Remember that members of the public form the jury.
Re: A/C off the runway in CPH
OVERTALK the differences in our views might only be balanced with data provided by tests which you called for. My experiences were from tests, which provided data, but only applied to a few aircraft. Further, wider discussion could debate the applicability of your beliefs or my experiences to other aircraft types, but without facts, we would be speculating, albeit from informed positions.
A more responsible view within a thread relating to one of several recent accidents is to focus on the facts, what the manufacturer advises. It would be remiss of us to advise others to try unproven techniques during a critical event; it is far better, as I believe we agree, that crews are encourage to focus on the basics.
I would willingly discuss this topic further off line, or in the flight testing forum.
I also believe we would agree on the contribution of human error in overrun accidents, but I do not subscribe to your view of error.
Recent views of human factors prefers to avoid stating that humans make errors; we do not deliberately set out to make an error. Error is a description of behavior applied after the event; it is one possible explanation of the event.
Thus, as an alternative view, humans are exposed to error provoking situations and may be predisposed to erroneous mind set or judgment based on experiences or knowledge.
This thread has already identified significant opportunities for error; we should not contribute further to any erroneous mind set with inappropriate knowledge however well intentioned.
A more responsible view within a thread relating to one of several recent accidents is to focus on the facts, what the manufacturer advises. It would be remiss of us to advise others to try unproven techniques during a critical event; it is far better, as I believe we agree, that crews are encourage to focus on the basics.
I would willingly discuss this topic further off line, or in the flight testing forum.
I also believe we would agree on the contribution of human error in overrun accidents, but I do not subscribe to your view of error.
Recent views of human factors prefers to avoid stating that humans make errors; we do not deliberately set out to make an error. Error is a description of behavior applied after the event; it is one possible explanation of the event.
Thus, as an alternative view, humans are exposed to error provoking situations and may be predisposed to erroneous mind set or judgment based on experiences or knowledge.
This thread has already identified significant opportunities for error; we should not contribute further to any erroneous mind set with inappropriate knowledge however well intentioned.