AW189
Dangermouse,
Just how do you expect the pilot to know the ground-speed?
As I said before, the flight test team had an instrumented aircraft. The pilot only has his ASI (or whatever is provided in the PFD/MFD for airspeed computations). If these procedures require an accurate speed to work, then there has to be provision of a method to establish it.
There will be occasions when the wind-speed is greater than the target ground-speed at the defined point - perhaps the flight manual should say something about that.
With respect to the Cert Authorities; they have not covered themselves in glory with respect to the other issues of H-V provision and the minimum helipad dimensions for Category A procedures (neither of which are in compliance with their own rules/guidance). What makes you think that they have this right?
Jim
Just how do you expect the pilot to know the ground-speed?
As I said before, the flight test team had an instrumented aircraft. The pilot only has his ASI (or whatever is provided in the PFD/MFD for airspeed computations). If these procedures require an accurate speed to work, then there has to be provision of a method to establish it.
There will be occasions when the wind-speed is greater than the target ground-speed at the defined point - perhaps the flight manual should say something about that.
With respect to the Cert Authorities; they have not covered themselves in glory with respect to the other issues of H-V provision and the minimum helipad dimensions for Category A procedures (neither of which are in compliance with their own rules/guidance). What makes you think that they have this right?
Jim
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With respect to Category A takekoff, the following guidance is provided on page B-38 of Advisory Circular 29-2C.
AC 29.59(b)(2)(i)...The CDP should be definable with the minimum crew using standard cockpit instrumentation.
AC 29.59(b)(2)(i)...The CDP should be definable with the minimum crew using standard cockpit instrumentation.
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Reply to Jim L
Jim,
IF you have access to the certified RFM, (which I do) you should have seen in the systems description on page 7-197 that GS is displayed all the time to the pilots on the PFD, therefore the techniques CAN be flown by the average pilot because all the data he needs to fly them is presented to him
You stated in an earlier post 'There is no Category A take-off mass WAT as specified in 29.25(a), 29.67(a)(2) and required by 29.1519 but this is not unusual for European helicopters certificated by EASA' forgive me but surely the charts do exist in the Cat A supplement to the RFM?.
as you appear to lack knowledge of GS being available and have no apparent knowledge of the existence of the certified Cat A WAT curves, please can you clarify to the readers of this post the source of your performance data.
BTW The point of the cert authorities is that they act an independent specialist assessors of the manufacturers data, if you don't believe that I am surprised you fly on anything.
DM
IF you have access to the certified RFM, (which I do) you should have seen in the systems description on page 7-197 that GS is displayed all the time to the pilots on the PFD, therefore the techniques CAN be flown by the average pilot because all the data he needs to fly them is presented to him
You stated in an earlier post 'There is no Category A take-off mass WAT as specified in 29.25(a), 29.67(a)(2) and required by 29.1519 but this is not unusual for European helicopters certificated by EASA' forgive me but surely the charts do exist in the Cat A supplement to the RFM?.
as you appear to lack knowledge of GS being available and have no apparent knowledge of the existence of the certified Cat A WAT curves, please can you clarify to the readers of this post the source of your performance data.
BTW The point of the cert authorities is that they act an independent specialist assessors of the manufacturers data, if you don't believe that I am surprised you fly on anything.
DM
Also AW are proposing a return to establishing the Isle of Scilly air link using the 189 by 2016
Helicopter manufacturer AgustaWestland eyes Scilly link | This is Money
Cheers
Helicopter manufacturer AgustaWestland eyes Scilly link | This is Money
Cheers
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With respect to the Cert Authorities; they have not covered themselves in glory with respect to the other issues of H-V provision and the minimum helipad dimensions for Category A procedures
AW189 Achieves EASA Certification | AgustaWestland
Less than three years after the AW189 was unveiled at Paris Air Show in June 2011 AgustaWestland has achieved EASA certification thanks to strong collaboration between the EASA and AgustaWestland teams.
Thanks dangermouse.
After some reflection and having considered what you have said about the use of groundspeed (GS) as a reference for the (low speed regime of) Category A procedures, I am persuaded that you are right.
Because the AW189 MFD is extremely busy, conspicuity of the ‘digital GS’ display below the ASI strip might be an issue – particularly if it is flown single pilot. The integrity of the DGPS signal also has to be assured as has its accuracy (this will have a knock on effect on the MMEL limitations of the Category A procedure because of the GS/DGPS requirement).
With respect to the issue of airspeed in excess of GS, the effects will always be beneficial because lower wind-speed is the limiting case. Although this does affect the continued take-off manoeuvre (ground speed up to 15kts, and groundspeed above 15 kts – what about the 15 kts case?), it is not of sufficient import to worry about.
I used to be of the same opinion as you with respect to the requirement for a Category A take-off mass – i.e. there is a WAT graph for each of the Category A procedures. However, the reason that there is a requirement for a Category A WAT in the ‘limitations’ section is because, even for a helicopter that is certificated in Category A, there is no compulsion to take-off or land within a Category A procedure. A good example of this is the offshore regime where Performance Class 2 is the requirement; however, this still has to be flown in compliance with the Category A take-off/landing mass.
There is also the case of the helicopter with more than 10 seats but not above the 9,072 kg (20,000 lbs) threshold (29.1(e)), for which only the basic Category A WAT is required. (Because the H-V Diagram (29.1517) is also mandated, the requirement aligns almost exactly with the Pure Performance Class 2 definition.)
The Category A mass limitation consists of a basic structural limitation (the MCTOM) and one that is associated with 29.67(a)(2) (the second segment climb) for all altitudes and temperatures specified in the approval. Yes, there are WAT curves in the Category A section, each associated with a set of procedures and the required profile, but these procedures/profiles are not always able to be flown (they might be unnecessarily limiting to the take-off/landing mass or the take-off/landing site might lack the facilities of a Performance Class 1 FATO). Yes, the graphs that show compliance with 29.67(a)(2)* are in the performance (information) section of the RFM but that does not show compliance with 29.1519.
* In fact there are two 'types' of WAT (four when anti-ice is taken into account): that for 2 min. OEI; and that for MCP OEI. Only the MCP OEI is required for compliance with the rule.
RFM that are approved by the Rotorcraft Directorate of the FAA have the Category A WAT in the limitations section.
Jim
After some reflection and having considered what you have said about the use of groundspeed (GS) as a reference for the (low speed regime of) Category A procedures, I am persuaded that you are right.
Because the AW189 MFD is extremely busy, conspicuity of the ‘digital GS’ display below the ASI strip might be an issue – particularly if it is flown single pilot. The integrity of the DGPS signal also has to be assured as has its accuracy (this will have a knock on effect on the MMEL limitations of the Category A procedure because of the GS/DGPS requirement).
With respect to the issue of airspeed in excess of GS, the effects will always be beneficial because lower wind-speed is the limiting case. Although this does affect the continued take-off manoeuvre (ground speed up to 15kts, and groundspeed above 15 kts – what about the 15 kts case?), it is not of sufficient import to worry about.
I used to be of the same opinion as you with respect to the requirement for a Category A take-off mass – i.e. there is a WAT graph for each of the Category A procedures. However, the reason that there is a requirement for a Category A WAT in the ‘limitations’ section is because, even for a helicopter that is certificated in Category A, there is no compulsion to take-off or land within a Category A procedure. A good example of this is the offshore regime where Performance Class 2 is the requirement; however, this still has to be flown in compliance with the Category A take-off/landing mass.
There is also the case of the helicopter with more than 10 seats but not above the 9,072 kg (20,000 lbs) threshold (29.1(e)), for which only the basic Category A WAT is required. (Because the H-V Diagram (29.1517) is also mandated, the requirement aligns almost exactly with the Pure Performance Class 2 definition.)
The Category A mass limitation consists of a basic structural limitation (the MCTOM) and one that is associated with 29.67(a)(2) (the second segment climb) for all altitudes and temperatures specified in the approval. Yes, there are WAT curves in the Category A section, each associated with a set of procedures and the required profile, but these procedures/profiles are not always able to be flown (they might be unnecessarily limiting to the take-off/landing mass or the take-off/landing site might lack the facilities of a Performance Class 1 FATO). Yes, the graphs that show compliance with 29.67(a)(2)* are in the performance (information) section of the RFM but that does not show compliance with 29.1519.
* In fact there are two 'types' of WAT (four when anti-ice is taken into account): that for 2 min. OEI; and that for MCP OEI. Only the MCP OEI is required for compliance with the rule.
RFM that are approved by the Rotorcraft Directorate of the FAA have the Category A WAT in the limitations section.
Jim
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A few more points for clarification
JimL
My understanding is that the Maufacturer has to meet CS27/29 regulations, which do not reflect any 'performance classes' therefore I am slightly confused as to why you think there is a problem here so please bear with me.
CAT-A
WAT charts are included and are defined as limitations for those kind of operations in the CAT-A supplement. The techniques describe a 2 part flight path ending at 1000 ft AGL with ROC of at least 150 fpm, hence compliant iaw 29.67 (2).
HV
As stated before the RFM of the 189 does not include traditional HV charts, they are replaced by a chart which gves the WAT data associated with 2 fixed procedures; a vertical landing and a flyway one.
The WAT chart gives the maximum mass for a safe vertical landing at any height up to 200 ft (very simple to understand)
The second set of WAT info calculates the height loss associated with the flyaway technique for given AUM/ambient conditions. This data is also summarised in table form (simpler to understand).
surely this does meet the requirement of 29.1517 (I think you made a typo in your post, 29.1519 refers to weight and CG limits), the aircraft is safe to vertical reject iaw the WAT chart if below 200 ft or safe to flyaway if hover height is greater than (height loss + clearance required).
Therefore I am unsure what the problem is, the data presented is compliant with the CS requirements, although not in the 'traditional' manner, and EASA agree
happy to be corrected on any of the above.
reagrding your earlier posting (17/8 15:05) I am having trouble finding the value of Takeoff mass you use (8050kg), the vertical WAT (fig 4A-2) gives 7904 kg, please clarify where that num,ber comes from
regards
DM
My understanding is that the Maufacturer has to meet CS27/29 regulations, which do not reflect any 'performance classes' therefore I am slightly confused as to why you think there is a problem here so please bear with me.
CAT-A
WAT charts are included and are defined as limitations for those kind of operations in the CAT-A supplement. The techniques describe a 2 part flight path ending at 1000 ft AGL with ROC of at least 150 fpm, hence compliant iaw 29.67 (2).
HV
As stated before the RFM of the 189 does not include traditional HV charts, they are replaced by a chart which gves the WAT data associated with 2 fixed procedures; a vertical landing and a flyway one.
The WAT chart gives the maximum mass for a safe vertical landing at any height up to 200 ft (very simple to understand)
The second set of WAT info calculates the height loss associated with the flyaway technique for given AUM/ambient conditions. This data is also summarised in table form (simpler to understand).
surely this does meet the requirement of 29.1517 (I think you made a typo in your post, 29.1519 refers to weight and CG limits), the aircraft is safe to vertical reject iaw the WAT chart if below 200 ft or safe to flyaway if hover height is greater than (height loss + clearance required).
Therefore I am unsure what the problem is, the data presented is compliant with the CS requirements, although not in the 'traditional' manner, and EASA agree
happy to be corrected on any of the above.
reagrding your earlier posting (17/8 15:05) I am having trouble finding the value of Takeoff mass you use (8050kg), the vertical WAT (fig 4A-2) gives 7904 kg, please clarify where that num,ber comes from
regards
DM
Hi dangermouse,
Let me take the easy one first: my value of 8,050 kg came from the Category A Vertical WAT (figure 4A-1 – anti-ice off), resulting from a pressure altitude of 0 ft and temperature of 15C (ISA conditions) and nil accountable wind. I may have overstated the figure if the starting line on the right is -20 and not -10 as I assumed. If that is the case then I apologise and accept your figure of 7904 kg (I still make it slightly more).
I have no comment on the Category A procedures (but would welcome an explanation for the rolling take-off in the clear area procedure).
If, for a moment, you accept my premise that a take-off, at the basic Category A mass (as defined in my previous post), can be made without applying the Category A procedures (for example on a rough strip where a rolling take-off would not be possible) i.e. a take-off mass of 8,300 kg, 396 kg above the vertical procedure WAT. You will see that I have no defined Category A WAT on which to base my take-off mass (in accordance with 29.1519) and no H-V Diagram on which to base my projected profile (in accordance with 29.1517). Whilst accepting that the reject/fly-away graphs are a great innovation and very welcome, only when they complete the circle and provide options right up to the basic Category A WAT, can they be said to replace the H-V Diagram.
What has been described above is not an unusual situation in operations because, to apply the Category A procedures – i.e. operate in Performance Class 1, the pilot must correctly apply the procedures/profile and fulfil the strenuous FATO requirements of surface condition, and minimum size (the rejected take-off distance). Outside of an airfield environment, these are as rare as hen’s teeth. However, I can operate: in Performance Class 2, to the basic Category A WAT - achieving a generally acceptable level of safety; and, in Performance Class 2 with exposure, to the basic Category A WAT (together with AEO HOGE in zero wind conditions) – achieving a measured level of safety.
Jim
Let me take the easy one first: my value of 8,050 kg came from the Category A Vertical WAT (figure 4A-1 – anti-ice off), resulting from a pressure altitude of 0 ft and temperature of 15C (ISA conditions) and nil accountable wind. I may have overstated the figure if the starting line on the right is -20 and not -10 as I assumed. If that is the case then I apologise and accept your figure of 7904 kg (I still make it slightly more).
I have no comment on the Category A procedures (but would welcome an explanation for the rolling take-off in the clear area procedure).
If, for a moment, you accept my premise that a take-off, at the basic Category A mass (as defined in my previous post), can be made without applying the Category A procedures (for example on a rough strip where a rolling take-off would not be possible) i.e. a take-off mass of 8,300 kg, 396 kg above the vertical procedure WAT. You will see that I have no defined Category A WAT on which to base my take-off mass (in accordance with 29.1519) and no H-V Diagram on which to base my projected profile (in accordance with 29.1517). Whilst accepting that the reject/fly-away graphs are a great innovation and very welcome, only when they complete the circle and provide options right up to the basic Category A WAT, can they be said to replace the H-V Diagram.
What has been described above is not an unusual situation in operations because, to apply the Category A procedures – i.e. operate in Performance Class 1, the pilot must correctly apply the procedures/profile and fulfil the strenuous FATO requirements of surface condition, and minimum size (the rejected take-off distance). Outside of an airfield environment, these are as rare as hen’s teeth. However, I can operate: in Performance Class 2, to the basic Category A WAT - achieving a generally acceptable level of safety; and, in Performance Class 2 with exposure, to the basic Category A WAT (together with AEO HOGE in zero wind conditions) – achieving a measured level of safety.
Jim
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more clarification (this is fascinating)
First the easy one
the chart is coloured, the right hand line is the same colour as the -20 text, the next one to the left is the same colour as the -10 text so you were using the wrong line (the value I got was from the table at fig 4A-2 which is a tabluar version of that chart)
OK let me go through this slow time as things are still not entirely clear to me (and maybe some others), I am not aware of the requirements for PC1 and PC2 are.
I am making the assumption that when you use the term 'basic Category A mass' you mean the maximum mass at which the aircraft is certified (ie 8300kg)
For this aircraft you only have 2 CAT A profiles, vertical or rolling, if you don't do either then surely the CAT A limits do not apply and you will be using the 'HV' data to plan you flying, ie a vertical reject within the WAT limits is OK upto 200 ft AGL or a flyaway provided the height loss allows it, or using CAT B WAT
In this case the 'HV' data gives a max AUM for a safe vertical landing less than 8300kg so doesn't that mean you can only takeoff at MTOW (8300kg) using a CAT A profile or using CAT B procedures with all that implies in terms of OEI capability.
As the Advisory circular for CS29 is that used on FAR29 then I agree arguably 29.1519 has not been met in the legal sense if you require an HV chart to cover max TO mass operations, is that your point?
maybe it's just a difference in view between EASA and FAA, prehaps when (and if) EASA get round to their own Advisory material it will be clearer
DM
the chart is coloured, the right hand line is the same colour as the -20 text, the next one to the left is the same colour as the -10 text so you were using the wrong line (the value I got was from the table at fig 4A-2 which is a tabluar version of that chart)
OK let me go through this slow time as things are still not entirely clear to me (and maybe some others), I am not aware of the requirements for PC1 and PC2 are.
I am making the assumption that when you use the term 'basic Category A mass' you mean the maximum mass at which the aircraft is certified (ie 8300kg)
For this aircraft you only have 2 CAT A profiles, vertical or rolling, if you don't do either then surely the CAT A limits do not apply and you will be using the 'HV' data to plan you flying, ie a vertical reject within the WAT limits is OK upto 200 ft AGL or a flyaway provided the height loss allows it, or using CAT B WAT
In this case the 'HV' data gives a max AUM for a safe vertical landing less than 8300kg so doesn't that mean you can only takeoff at MTOW (8300kg) using a CAT A profile or using CAT B procedures with all that implies in terms of OEI capability.
As the Advisory circular for CS29 is that used on FAR29 then I agree arguably 29.1519 has not been met in the legal sense if you require an HV chart to cover max TO mass operations, is that your point?
maybe it's just a difference in view between EASA and FAA, prehaps when (and if) EASA get round to their own Advisory material it will be clearer
DM
Thanks dangermouse.
I obviously have an early version of the chart because it is not colour coordinated.
Before attempting to make an input to your post, it might be a good idea to explain some of the reasons this debate is taking place. No area of aviation exists in isolation; whilst your statement on the requirement for showing compliance with the appropriate certification code is correct, the ultimate reason for the provision of standards, limitations, information and data is to provide operations with qualified helicopters, procedures and (for the purpose of this debate) performance information.
AW responsibilities to the code are in some sense finite and static; however the code has an intent which (whilst not always obvious) can, with examination of the history, be divined quite clearly (because it is well documented). Operations on the other hand are dynamic and as broad as the imagination of the customer, operator and pilot. To plot a safe route through such an operational environment needs data and information that doesn’t require us to fly on rails.
Anyway, on with the subject at hand.
The best way to describe the ‘Category A mass’ is to use Part 29.1(e) as the example: it requires the manufacturer to provide “the Category A requirements of 29.67(a)(2), 29.87, 29.1517…”. No compliance with the other Category A rules of Subpart B – Flight, are mandated and compliance with Subpart G – Operating Limitations and Information, is assumed (including 29.1519 – referring to 29.25(a)(1) to (3)). Because there is no requirement for Category A take-off and landing procedures, this leads to a necessity for a ‘Category A mass’ without any presumption of the take-off profile (only that it must remain clear of the H-V Diagram).
Operating in Performance Class 1 correlates quite closely with Category A procedures but is not currently required in the US and, in Europe, required only for operations in a built-up area or when carrying more than 19 passengers (with a derogation for more than 19 passengers offshore). Operations in Performance Class 2 are used the majority of the time (and specifically for offshore landing/take-off). So whilst Category A procedures are required for occasions when ‘mandated’ or, when they can be used without payload penalty, it is operations in Performance Class 2 that are predominant and the driver for flexible performance information/data.
In essence, this illustrates the issue; the Category A clear area procedure is too restrictive, the Category A Vertical procedure is payload limiting (as is the Vertical reject) and the Category B profile requires level acceleration to achieve flight clear of the H-V avoid curve (and doesn’t provide second segment climb compliance in the WAT).
Yes it is ‘a’ point, but used only as an illustration that there is a space in the information provided by the reject/fly-away graphs between the upper limits of the reject curve and the maximum Category A mass (the mass meeting the ‘design maximum mass (structural)’ and ‘the highest mass at which compliance with 29.67(a)(2) is shown’) – (for offshore operations) 8,300 kg. There is no doubt in my mind that the gap can be filled, but not with a traditional H-V Diagram. If this information is not provided, then compliance with 29.1517 has not be shown unless Category A procedures, Category B procedures (remaining clear of the H-V curve), or the reject/fly-away graphs are mandated in the limitations section. Not really the result that we want for a new type of helicopter.
Jim
I obviously have an early version of the chart because it is not colour coordinated.
Before attempting to make an input to your post, it might be a good idea to explain some of the reasons this debate is taking place. No area of aviation exists in isolation; whilst your statement on the requirement for showing compliance with the appropriate certification code is correct, the ultimate reason for the provision of standards, limitations, information and data is to provide operations with qualified helicopters, procedures and (for the purpose of this debate) performance information.
AW responsibilities to the code are in some sense finite and static; however the code has an intent which (whilst not always obvious) can, with examination of the history, be divined quite clearly (because it is well documented). Operations on the other hand are dynamic and as broad as the imagination of the customer, operator and pilot. To plot a safe route through such an operational environment needs data and information that doesn’t require us to fly on rails.
Anyway, on with the subject at hand.
The best way to describe the ‘Category A mass’ is to use Part 29.1(e) as the example: it requires the manufacturer to provide “the Category A requirements of 29.67(a)(2), 29.87, 29.1517…”. No compliance with the other Category A rules of Subpart B – Flight, are mandated and compliance with Subpart G – Operating Limitations and Information, is assumed (including 29.1519 – referring to 29.25(a)(1) to (3)). Because there is no requirement for Category A take-off and landing procedures, this leads to a necessity for a ‘Category A mass’ without any presumption of the take-off profile (only that it must remain clear of the H-V Diagram).
Operating in Performance Class 1 correlates quite closely with Category A procedures but is not currently required in the US and, in Europe, required only for operations in a built-up area or when carrying more than 19 passengers (with a derogation for more than 19 passengers offshore). Operations in Performance Class 2 are used the majority of the time (and specifically for offshore landing/take-off). So whilst Category A procedures are required for occasions when ‘mandated’ or, when they can be used without payload penalty, it is operations in Performance Class 2 that are predominant and the driver for flexible performance information/data.
For this aircraft you only have 2 CAT A profiles, vertical or rolling, if you don't do either then surely the CAT A limits do not apply and you will be using the 'HV' data to plan you flying, ie a vertical reject within the WAT limits is OK up to 200 ft AGL or a flyaway provided the height loss allows it, or using CAT B WAT
As the Advisory circular for CS29 is that used on FAR29 then I agree arguably 29.1519 has not been met in the legal sense if you require an HV chart to cover max TO mass operations, is that your point?
Jim
’thought for the day’
Now that the intent of Part 29.1, and its associated clauses are (hopefully) clearer, it can be seen that the taxonomy - used as a bridge between the 'certification' and 'performance' codes in Europe, and the basis for regulation of 'performance' in the US - has been disrupted by the reluctance of EASA to correct the error made when they transferred the requirement to apply RFM Limitations from regulations to the Law - see the discussion in the HV thread:
http://www.pprune.org/rotorheads/544...mitations.html
Instead of correcting that error and reinstating the alleviation from the H-V Diagram, when operating in accordance with the ‘Exposure Approval’, EASA are attempting to reshuffle the requirements (both certification and operational) to suit their purpose. (Perhaps observance of the principle of Occam’s Razor should be their maxim.)
When AW applied for an Equivalent Safety (ES) ruling, replacing the HV Diagram with the fly-away and reject graphs, EASA saw an opportunity without seeing the pitfalls in the logic - i.e. the gap between the Category A WAT (8,300 kg) and the top end of the reject curve, resulting in a concomitant lack of compliance with 29.1517. (This was clearly pointed out to EASA in a comment to the published ES proposal.)
http://easa.europa.eu/system/files/d...1587(b)(6).pdf
The situation has also been compounded by a misunderstanding of the certification requirements, resulting in the omission of: the Category A, and B, H-V Diagrams (in compliance with 29.1517); and, the basic Category A WAT (in compliance with 29.1519) from the Limitations Section of European RFMs (as found in FAA approved RFMs – see the S92). Most of which are required in showing compliance with the requirements of Performance Class 2 (modified, as required, by alleviations permitted when operating with exposure).
As was said earlier, AW have done a great service to the industry by providing the principle of ‘reject’ and ‘fly-away’ graphs - thus providing a toolkit for the construction of Performance Class 2 profiles to suit most sites. What is missing (and probably on the AW agenda) is: a WAT graph to close the gap between the Category A WAT and the top end of the ‘reject’ curve; and, the provision of a practical profile to achieve deck-edge clearance on an elevated heliport or helideck departure. The latter one might already be part of the Category A Helideck Procedure which has not yet been added to Supplement 4 of the RFM.
Without the latter it is difficult to see how compliance with CAT.POL.H.310(c)(2)(ii):
can be shown.
Jim
Now that the intent of Part 29.1, and its associated clauses are (hopefully) clearer, it can be seen that the taxonomy - used as a bridge between the 'certification' and 'performance' codes in Europe, and the basis for regulation of 'performance' in the US - has been disrupted by the reluctance of EASA to correct the error made when they transferred the requirement to apply RFM Limitations from regulations to the Law - see the discussion in the HV thread:
http://www.pprune.org/rotorheads/544...mitations.html
Instead of correcting that error and reinstating the alleviation from the H-V Diagram, when operating in accordance with the ‘Exposure Approval’, EASA are attempting to reshuffle the requirements (both certification and operational) to suit their purpose. (Perhaps observance of the principle of Occam’s Razor should be their maxim.)
When AW applied for an Equivalent Safety (ES) ruling, replacing the HV Diagram with the fly-away and reject graphs, EASA saw an opportunity without seeing the pitfalls in the logic - i.e. the gap between the Category A WAT (8,300 kg) and the top end of the reject curve, resulting in a concomitant lack of compliance with 29.1517. (This was clearly pointed out to EASA in a comment to the published ES proposal.)
http://easa.europa.eu/system/files/d...1587(b)(6).pdf
The situation has also been compounded by a misunderstanding of the certification requirements, resulting in the omission of: the Category A, and B, H-V Diagrams (in compliance with 29.1517); and, the basic Category A WAT (in compliance with 29.1519) from the Limitations Section of European RFMs (as found in FAA approved RFMs – see the S92). Most of which are required in showing compliance with the requirements of Performance Class 2 (modified, as required, by alleviations permitted when operating with exposure).
As was said earlier, AW have done a great service to the industry by providing the principle of ‘reject’ and ‘fly-away’ graphs - thus providing a toolkit for the construction of Performance Class 2 profiles to suit most sites. What is missing (and probably on the AW agenda) is: a WAT graph to close the gap between the Category A WAT and the top end of the ‘reject’ curve; and, the provision of a practical profile to achieve deck-edge clearance on an elevated heliport or helideck departure. The latter one might already be part of the Category A Helideck Procedure which has not yet been added to Supplement 4 of the RFM.
Without the latter it is difficult to see how compliance with CAT.POL.H.310(c)(2)(ii):
(ii) any helicopter operated from a helideck located in a hostile environment,
the take-off mass shall take into account: the procedure; deck-edge miss and drop down appropriate to the height of the helideck with the critical engine(s) inoperative and the remaining engines operating at an appropriate power rating.
the take-off mass shall take into account: the procedure; deck-edge miss and drop down appropriate to the height of the helideck with the critical engine(s) inoperative and the remaining engines operating at an appropriate power rating.
Jim
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Clarifications on airfield performance
Hi Folks
I would like to post some clarifications on the very interesting discussion develloped here.
I like first to assure everybody that AW189 has been certified and is fully compliance with all the applicable rules and no exemptions have been made.
H-V
In AW we are convinced that the CS29 H-V regulations, particularly for twin engines is out of date and needs to be revisited in order to provide a much more practical and operational information.
The traditional H-V chart does not provide much to the operator other than data for which a potential HOGE engine failure could be catastrophic without providing a real operational scenario and way out procedures. Furthermore traditional H-V charts are only valid for the type of published surface that is usually a runway type that is almost never the situation for takeoff/landing and OGE operations in real life.
For this reason we went for a "non traditional" H-V charts that in our opininon provide what a pilot needs to know when is hovering OGE (IGE section is automatically incorporated in the Cat B and Cat A takeoff and landing procedures/WAT).
We do hope that this way of presenting H-V data will be welcomed by the operators and AAs as well (EASA has already).
Cat B
The published Cat B procedures fully comply with the requirements for the takeoff profile up to 50 ft and climbout speed and for the OEI Continnuous climb performance requirements. The published WATs cover these procedures for zero wind takeoff/OEI landings, for any wind effect, dedicated WAT charts are published for both HIGE (takeoff and landings) an HOGE.
The published procedures cover both HIGE depart style and rolling takeoff from available runways.
Cat A
We currently pubblished only Runway, and ground/elevated helipad (including a shallow landing approach to allow more weight when feasable).
For the Runway (Clear Area) we elected to provide a rolling style manoeuver for a very simple reason:[LIST][*]our helicopters have wheels, why not use them?[*]this technique is much more passanger friendly[*]If an engine fails before lift off, no big deal
But we are also open to provide a traditional HIGE depart if this would be required even though a Cat A reject must always be demonstrated on a suitable surface that can accomodate it that is usually a runway for this kind of procedure.
The vertical helipad procedure is provided for helipad size of at least 20x20 m and can easily be accomplished with always the ground in sight. 110 ft is considered safe and easy to achieve. This manoeuver is very passenger friendly in all phases and not aggressive in case of any emergency.
This procedure is meant for ground base helipads.
The shallow helipad approach is a traditional helipad landing style
As per our company attitude, we will be providing also a dedicated offshore helideck Cat A procedure (like the 139) that will be certified a later date.
I hope this helps in understanding the reasons behind the 189 procedures/performance and opens a profitable discussion.
I would like to post some clarifications on the very interesting discussion develloped here.
I like first to assure everybody that AW189 has been certified and is fully compliance with all the applicable rules and no exemptions have been made.
H-V
In AW we are convinced that the CS29 H-V regulations, particularly for twin engines is out of date and needs to be revisited in order to provide a much more practical and operational information.
The traditional H-V chart does not provide much to the operator other than data for which a potential HOGE engine failure could be catastrophic without providing a real operational scenario and way out procedures. Furthermore traditional H-V charts are only valid for the type of published surface that is usually a runway type that is almost never the situation for takeoff/landing and OGE operations in real life.
For this reason we went for a "non traditional" H-V charts that in our opininon provide what a pilot needs to know when is hovering OGE (IGE section is automatically incorporated in the Cat B and Cat A takeoff and landing procedures/WAT).
We do hope that this way of presenting H-V data will be welcomed by the operators and AAs as well (EASA has already).
Cat B
The published Cat B procedures fully comply with the requirements for the takeoff profile up to 50 ft and climbout speed and for the OEI Continnuous climb performance requirements. The published WATs cover these procedures for zero wind takeoff/OEI landings, for any wind effect, dedicated WAT charts are published for both HIGE (takeoff and landings) an HOGE.
The published procedures cover both HIGE depart style and rolling takeoff from available runways.
Cat A
We currently pubblished only Runway, and ground/elevated helipad (including a shallow landing approach to allow more weight when feasable).
For the Runway (Clear Area) we elected to provide a rolling style manoeuver for a very simple reason:[LIST][*]our helicopters have wheels, why not use them?[*]this technique is much more passanger friendly[*]If an engine fails before lift off, no big deal
But we are also open to provide a traditional HIGE depart if this would be required even though a Cat A reject must always be demonstrated on a suitable surface that can accomodate it that is usually a runway for this kind of procedure.
The vertical helipad procedure is provided for helipad size of at least 20x20 m and can easily be accomplished with always the ground in sight. 110 ft is considered safe and easy to achieve. This manoeuver is very passenger friendly in all phases and not aggressive in case of any emergency.
This procedure is meant for ground base helipads.
The shallow helipad approach is a traditional helipad landing style
As per our company attitude, we will be providing also a dedicated offshore helideck Cat A procedure (like the 139) that will be certified a later date.
I hope this helps in understanding the reasons behind the 189 procedures/performance and opens a profitable discussion.
In answer to a question by Geoffer' on the application of the Category A procedures, I have posted on the HV Thread:
http://www.pprune.org/rotorheads/544...ml#post8650953
It probably has just as much relevance to this thread as the other.
Jim
http://www.pprune.org/rotorheads/544...ml#post8650953
It probably has just as much relevance to this thread as the other.
Jim
Gulf Helicopters receives 2 AW189 super medium helicopters
Gulf Helicopters (GHC), a wholly-owned subsidiary of Gulf International Services, has taken delivery of the first two AW189 super medium helicopters in offshore configuration.
This is part of the 15 AW189s on order and the delivery of the whole batch of aircraft is now scheduled to be completed by 2017, a spokesman of GIS said in a communiqué to the Qatar Stock Exchange.
GHC, already a major AW139 operator, becomes the first customer in the Middle East to introduce the AgustaWestland Family concept into operational service. It was also established as an AgustaWestland authorised training centre for the AW139 and AW189 in September 2013 and ordered the first AW189 Full Flight Simulator (FFS) in the region in February 2014.
“Our recent acceptance of delivery of our first two AW 189s is based not only on our marketing strategy for the future of the company’s expansion, but also on our customers’ requests for such a helicopter size,” GHC CEO Mohamed al-Mohannadi said.
These two deliveries are in line with GHC’s expansion plans and specially cater to contracting with international oil companies outside of Qatar, which is expected to increase the company’s revenue and profitability, the spokesman said.
GHC, being one of the largest helicopter operators in the Middle East, is also building on training capabilities in general and is also developing further as an AgustaWestland Training Center and a Regional Hub, in particular.
The AW189 was designed in response to growing market demand for a versatile, affordable, multirole super medium class helicopter. The new 8.3-tonne, twin engine helicopter is optimised for long range offshore transport and SAR (search and rescue) missions and has already received over 130 orders, including options and framework agreements, in more than 10 countries from 15 customers, making it the outright market leader in its class.
The spacious cabin is configured with 16 seats as standard with the option for a high density 18 seat lay out or a long range 12 seat configuration. The cockpit design, incorporating the latest in advanced situational awareness technologies, reduces crew workload and enhances safety.
The AW189, which meets the very latest international regulatory safety requirements, is unique in having a 50 minute ‘run-dry’ capable main gear box, exceeding current certification standards and offering unmatched safety and reliability for long range offshore operations.
This is part of the 15 AW189s on order and the delivery of the whole batch of aircraft is now scheduled to be completed by 2017, a spokesman of GIS said in a communiqué to the Qatar Stock Exchange.
GHC, already a major AW139 operator, becomes the first customer in the Middle East to introduce the AgustaWestland Family concept into operational service. It was also established as an AgustaWestland authorised training centre for the AW139 and AW189 in September 2013 and ordered the first AW189 Full Flight Simulator (FFS) in the region in February 2014.
“Our recent acceptance of delivery of our first two AW 189s is based not only on our marketing strategy for the future of the company’s expansion, but also on our customers’ requests for such a helicopter size,” GHC CEO Mohamed al-Mohannadi said.
These two deliveries are in line with GHC’s expansion plans and specially cater to contracting with international oil companies outside of Qatar, which is expected to increase the company’s revenue and profitability, the spokesman said.
GHC, being one of the largest helicopter operators in the Middle East, is also building on training capabilities in general and is also developing further as an AgustaWestland Training Center and a Regional Hub, in particular.
The AW189 was designed in response to growing market demand for a versatile, affordable, multirole super medium class helicopter. The new 8.3-tonne, twin engine helicopter is optimised for long range offshore transport and SAR (search and rescue) missions and has already received over 130 orders, including options and framework agreements, in more than 10 countries from 15 customers, making it the outright market leader in its class.
The spacious cabin is configured with 16 seats as standard with the option for a high density 18 seat lay out or a long range 12 seat configuration. The cockpit design, incorporating the latest in advanced situational awareness technologies, reduces crew workload and enhances safety.
The AW189, which meets the very latest international regulatory safety requirements, is unique in having a 50 minute ‘run-dry’ capable main gear box, exceeding current certification standards and offering unmatched safety and reliability for long range offshore operations.
I would like to tidy up my comments on this thread with my conclusions on the AW189 ESF CS 29.1587(b)(6) (these conclusions are an extract from Appendix A of the Response to NPA 2014-19 document posted on the H-V thread):
Conclusions on the AW189 Equivalent Safety Findings on CS 29.1578(b)(6)
Although the initiative to supply graphs that can be used to provide take-off and landing profiles in Performance Class 2 (and for ‘aerial work’ activities) is a move in the direction to removing the H-V Diagram as a Limitation, the boundaries of the ‘reject’ graph fall short of the requirements in CS 29.87, CS 29.1517, CS 29.1583 and CS 29.1587 on a number of counts:
At the time when the ESF was approved, the AW189 was being introduced to offshore operations without a Category A Helideck Procedure in the RFM. If Category A procedures are mandated, this results in offshore operations in contravention to the RFM!
Even if a Category A Helideck procedure is introduced, there will be circumstances where complying with the procedure is not possible for environmental reasons. This is why there has never been a proposal for the introduction of operations in Performance Class 1 to Helidecks.
Although this equivalent safety finding is ostensibly concerned with the alternative method of providing information for compliance with CS 29.1587(b)(6), it is confounded by a lack of compliance with CS 29.1517 and CS 29.1583(f).
Jim
Conclusions on the AW189 Equivalent Safety Findings on CS 29.1578(b)(6)
Although the initiative to supply graphs that can be used to provide take-off and landing profiles in Performance Class 2 (and for ‘aerial work’ activities) is a move in the direction to removing the H-V Diagram as a Limitation, the boundaries of the ‘reject’ graph fall short of the requirements in CS 29.87, CS 29.1517, CS 29.1583 and CS 29.1587 on a number of counts:
1. The upper boundary of the ‘reject’ graph does not extended to the maximum mass specified in the RFM and therefore does not provide compliance with CS 29.87(a).
2. A failure to comply with CS 29.87(a) prevents compliance with CS 29.1587(b)(6).
Note: Compliance with 29.1587(b)(6) can be satisfied if compliance with 29.1583(f) is provided.
3. A failure to comply with CS 29.87(a) prevents compliance with CS 29.1517.
4. A failure to comply with CS 29.1517 prevents compliance with CS 29.1583(f).
Note: Compliance is not required of CS 29.1583(f) if the Category A procedures are in the limitations section or, are contained elsewhere and mandated by a statement/pointer in the limitations section.
It is not clear, from the contents of the limitations section, if the Category A procedures of the AW189 are, or are not, mandated. This is not an issue that is confined to the AW189 but is also observed in the AW139 RFM. By not showing compliance with CS 29.1853(f) (pointing to CS 29.1517), the requirement to apply the Category A procedures is indeterminate. Mandating the Category A procedures would seriously inhibit operations to other than airfields. It would prevent operations in Performance Class 2 under circumstances where such operations have been safely conducted since the introduction of the Performance Classes. 2. A failure to comply with CS 29.87(a) prevents compliance with CS 29.1587(b)(6).
Note: Compliance with 29.1587(b)(6) can be satisfied if compliance with 29.1583(f) is provided.
3. A failure to comply with CS 29.87(a) prevents compliance with CS 29.1517.
4. A failure to comply with CS 29.1517 prevents compliance with CS 29.1583(f).
Note: Compliance is not required of CS 29.1583(f) if the Category A procedures are in the limitations section or, are contained elsewhere and mandated by a statement/pointer in the limitations section.
At the time when the ESF was approved, the AW189 was being introduced to offshore operations without a Category A Helideck Procedure in the RFM. If Category A procedures are mandated, this results in offshore operations in contravention to the RFM!
Even if a Category A Helideck procedure is introduced, there will be circumstances where complying with the procedure is not possible for environmental reasons. This is why there has never been a proposal for the introduction of operations in Performance Class 1 to Helidecks.
Although this equivalent safety finding is ostensibly concerned with the alternative method of providing information for compliance with CS 29.1587(b)(6), it is confounded by a lack of compliance with CS 29.1517 and CS 29.1583(f).
Jim
Join Date: Aug 2001
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Yes Jim, but in the real world...
... where life is a bit more complicated than we would really like all the discussions about Cat A offshore founder on the need for practical solutions that are easily understood and easily replicated in a huge variety of situations. These vary from the heli-deck on the northernmost platforms that are 200 feet ASL to the nasty little monopole flat tops in the southern North Sea that are just under your 'D' size and the lay-barge decks 25 feet above the waves. There is an almost infinite variety of deck shapes and sizes and many in very testing environments. To imagine these global operations are policed to EASA standards is wishful thinking - even in Europe in my opinion!
It wasn't so long ago that the ops manual of a major operator laid down the procedure for take offs with the S76A+. It said 'the pilot can make three attempts at taking off but if there is insufficient vertical performance the pilot must, after the third attempt, remove a passenger or sufficient cargo to facilitate a departure.'
It's a daft idea I know but can you imagine the pilot of a 747 being told the same thing - yes daft - but you can see where I am coming from. Cat A?? Makes me laugh.
The subtleties and complexities of these rules are lost on most and what we need instead is a basic awareness about the relationship between mass and safety. The nearer you are to your maximum the smaller the safety margins. Simple guidelines set out by the CP can be a great help.
G.
It wasn't so long ago that the ops manual of a major operator laid down the procedure for take offs with the S76A+. It said 'the pilot can make three attempts at taking off but if there is insufficient vertical performance the pilot must, after the third attempt, remove a passenger or sufficient cargo to facilitate a departure.'
It's a daft idea I know but can you imagine the pilot of a 747 being told the same thing - yes daft - but you can see where I am coming from. Cat A?? Makes me laugh.
The subtleties and complexities of these rules are lost on most and what we need instead is a basic awareness about the relationship between mass and safety. The nearer you are to your maximum the smaller the safety margins. Simple guidelines set out by the CP can be a great help.
G.
Soooooo.... With the SAR 189 now certified and with a MTOW of 8.6t, will the "normal" 189 be getting a MTOW increase soon to match the SAR bird?
Structurally they are the same, bar the extra fuel tanks.
Structurally they are the same, bar the extra fuel tanks.