Night offshore landings: a new approach?
Just found this text in EASA OPS - it may already have been in EU-OPS
Looks like the regulator already had it covered!
Jim
Additional specific training when not using the CDFA technique with level flight at or above MDA/H:
a. The training should detail:
a. The training should detail:
i. the need to facilitate CRM; with appropriate flight crew communication in particular;
ii. the additional known safety risks associated with the ‘dive-and-drive’ approach philosophy which may be associated with non-CDFA;
iii. the use of DA/H during approaches flown using the CDFA technique;
iv. the significance of the MDA/H and the MAPt where appropriate;
v. the actions to be taken at the MAPt and the need to ensure that the aeroplane remains in a stable condition and on the nominal and appropriate vertical profile until the landing;
vi. the reasons for increased RVR/Visibility minima when compared to the application of CDFA;
vii. the possible increased obstacle infringement risk when undertaking level flight at MDA/H without the required visual references;
viii. the need to accomplish a prompt go-around manoeuvre if the required visual reference is lost;
ix. the increased risk of an unstable final approach and an associated unsafe landing if a rushed approach is attempted either from: and
ii. the additional known safety risks associated with the ‘dive-and-drive’ approach philosophy which may be associated with non-CDFA;
iii. the use of DA/H during approaches flown using the CDFA technique;
iv. the significance of the MDA/H and the MAPt where appropriate;
v. the actions to be taken at the MAPt and the need to ensure that the aeroplane remains in a stable condition and on the nominal and appropriate vertical profile until the landing;
vi. the reasons for increased RVR/Visibility minima when compared to the application of CDFA;
vii. the possible increased obstacle infringement risk when undertaking level flight at MDA/H without the required visual references;
viii. the need to accomplish a prompt go-around manoeuvre if the required visual reference is lost;
ix. the increased risk of an unstable final approach and an associated unsafe landing if a rushed approach is attempted either from: and
1. inappropriate and close-in acquisition of the required visual reference; or
2. unstable aeroplane energy and or flight path control; and
x. J. The increased risk of CFIT (see introduction).2. unstable aeroplane energy and or flight path control; and
Jim
Bless the Regulator's Pea Picking Heart then JimL!
Now answer the question as to why the Regulator failed to ensure that was not adhered to by the Operators?
Having neat stuff archived away and hidden amongst tens of thousands of pages of stuff speaks well of the system doesn't it?
Perhaps DB should be head hunted by the CAA or EASA folks!
Now answer the question as to why the Regulator failed to ensure that was not adhered to by the Operators?
Having neat stuff archived away and hidden amongst tens of thousands of pages of stuff speaks well of the system doesn't it?
Perhaps DB should be head hunted by the CAA or EASA folks!
SASless,
For the very good reason that it comes from:
and describes, not only the continuous descent procedure, but also the perils of the approach without vertical guidance. For reason we have already enumerated, the ARA is not suited to the continuous descent approach; the beauty of this guidance material is that it examines the issue in great depth and provides advice in the cases where continuous descent procedures cannot be applied.
This is not just applicable to ARAs, the work that has been done on Point in Space (PinS) procedures can also put us in a position where continuous descent is not an option (i.e. where the MAPt is positioned to provide a missed approach in those cases where putting it closer to the heliport would raise it to an impractical level). In this case, there is a level approach segment (from the MAPt) which lead to a Descent Point (DP).
I hesitate to say this but there was no necessity for the invention of terms undertaken by DB (and in this thread); a reading of the Standard for the PinS in ICAO Doc 8186 (PANS OPS) would have provided enough clues. It was only when I had occasion to revisit the ICAO text (for an exchange of emails on hospital PinS procedures in France) that I remembered discussions leading to their provision.
Why is the guidance restricted to aeroplanes? You know as well as I do that helicopters are not considered to be real aircraft in the sense of IFR! Look at the lead in paragraph to the guidance:
and in cases where it is not appropriate:
(as for the reference to the visual cues required for non-precision approaches - don't bother to look for them in OPS.GEN.150 they are not there. They have magically appeared in the text that was originally provided for 'commencement and continuation of approach' - i.e. the text in JAR-OPS that was concerned with the 'approach ban'.)
and also:
As for the question aimed at the regulator; they must answer for themselves. As must the operators who should, perhaps, be aware of this type of guidance.
Jim
For the very good reason that it comes from:
GM2 OPS.GEN.150.A Instrument Flight Rules (IFR) operating minima
AERODROME MINIMA - CONTINUOUS DESCENT FINAL APPROACH (CDFA) – AEROPLANES
AERODROME MINIMA - CONTINUOUS DESCENT FINAL APPROACH (CDFA) – AEROPLANES
This is not just applicable to ARAs, the work that has been done on Point in Space (PinS) procedures can also put us in a position where continuous descent is not an option (i.e. where the MAPt is positioned to provide a missed approach in those cases where putting it closer to the heliport would raise it to an impractical level). In this case, there is a level approach segment (from the MAPt) which lead to a Descent Point (DP).
I hesitate to say this but there was no necessity for the invention of terms undertaken by DB (and in this thread); a reading of the Standard for the PinS in ICAO Doc 8186 (PANS OPS) would have provided enough clues. It was only when I had occasion to revisit the ICAO text (for an exchange of emails on hospital PinS procedures in France) that I remembered discussions leading to their provision.
Why is the guidance restricted to aeroplanes? You know as well as I do that helicopters are not considered to be real aircraft in the sense of IFR! Look at the lead in paragraph to the guidance:
Controlled Flight Into Terrain (CFIT) is a major causal category of accident and hull loss in commercial aviation. Most CFIT accidents occur in the final approach segment of non-precision approaches; the use of stabilised-approach criteria on a continuous descent with a constant, pre-determined vertical path is seen as a major improvement in safety during the conduct of such approaches. Operators should ensure that the following techniques are adopted as widely as possible, for all approaches;
Visual reference and path-control below MDA/H when not using the CDFA technique. In addition to the requirements stated in OPS.GEN.150 and its AMC material the pilot should have attained a combination of visual cues to safely control the aeroplane in roll and pitch to maintain the final approach path to landing. This should be included in the standard operating procedures and reflected in the operations manual.
and also:
The operator should provide the flight crew with unambiguous details of the technique used (CDFA or not).
Jim
When there is a void.....anything that fills it should not be criticized.
DB has done a good thing here....as he has not only defined a problem but has offered up an excellent remedy for it as well.
He has shown a willingness to incorporate changes that enhance the wording and concept.
So....will the CAA slowly creep aboard and embrace his ideas or will they produce yet another expensive study....offer up their version of the changes and then demand Operators comply with their viersion rather than letting the industry arrive at a "best practices" solution?
Worse yet....will they object and undermine the changes as it was NIH?
DB has done a good thing here....as he has not only defined a problem but has offered up an excellent remedy for it as well.
He has shown a willingness to incorporate changes that enhance the wording and concept.
So....will the CAA slowly creep aboard and embrace his ideas or will they produce yet another expensive study....offer up their version of the changes and then demand Operators comply with their viersion rather than letting the industry arrive at a "best practices" solution?
Worse yet....will they object and undermine the changes as it was NIH?
Work is progressing on the definition of an alternative ARA procedure (taking advantage of SBAS and providing omni-directional, offset, automatic approaches and eliminating necessity for a turn at the OIP) - a report will be issued quite soon.
It is my understanding that, as part of that work, there will be series of interviews conducted in Aberdeen with training-captains and line-pilots of the two larger operators to seek their views on the efficacy of, and problems with, the existing ARA.
These interviews will be scheduled for a two-week period starting in the third week of June, at a place and time convenient to the operators and pilots. The interviews will concentrate on the visual segment of the approach and be used in the provision of a hazard analysis.
This is just a heads-up so that you will be aware that this activity is being planned.
Jim
It is my understanding that, as part of that work, there will be series of interviews conducted in Aberdeen with training-captains and line-pilots of the two larger operators to seek their views on the efficacy of, and problems with, the existing ARA.
These interviews will be scheduled for a two-week period starting in the third week of June, at a place and time convenient to the operators and pilots. The interviews will concentrate on the visual segment of the approach and be used in the provision of a hazard analysis.
This is just a heads-up so that you will be aware that this activity is being planned.
Jim
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JimL,
On the 4th June, your post stated that interviews would take place in Aberdeen during the third week of June.
Did these take place? I work with one of the 'two larger operators' and I was in at work during that period and saw no sign of anyone doing interviews.
So what happened?
bondu
On the 4th June, your post stated that interviews would take place in Aberdeen during the third week of June.
Did these take place? I work with one of the 'two larger operators' and I was in at work during that period and saw no sign of anyone doing interviews.
So what happened?
bondu
Bondu,
Yes they did and the results are being analysed at this time; there was extensive prep before the interviews were conducted, part of which was to utilise experienced staff (not necessarily management) from the three operators to set up the interviews.
The interviewer was an MSc student from Cranfield University who intended to use the results for his final dissertation - he is an ex-Brazilian naval pilot. the CAA maintained oversight of the project which was, essentially, a risk assessment of the visual segment of the procedure.
The results will not correlate exactly with the CAA research work which is primarily concerned with the proposed SBAS Point in Space procedure -that being an offset procedure where the current ARA is a divergent procedure. The essential difference between the two (at least the point of the DR or MAPt - i.e. where the visual segment begins) is the amount of manoeuvring required to put the aircraft on a track to where the landing manoeuvre takes place. It is less with the divergent procedure.
All questions will have been with respect to the existing procedure; notwithstanding that, the principles are still the same and apply equally to both procedures.
Jim
Yes they did and the results are being analysed at this time; there was extensive prep before the interviews were conducted, part of which was to utilise experienced staff (not necessarily management) from the three operators to set up the interviews.
The interviewer was an MSc student from Cranfield University who intended to use the results for his final dissertation - he is an ex-Brazilian naval pilot. the CAA maintained oversight of the project which was, essentially, a risk assessment of the visual segment of the procedure.
The results will not correlate exactly with the CAA research work which is primarily concerned with the proposed SBAS Point in Space procedure -that being an offset procedure where the current ARA is a divergent procedure. The essential difference between the two (at least the point of the DR or MAPt - i.e. where the visual segment begins) is the amount of manoeuvring required to put the aircraft on a track to where the landing manoeuvre takes place. It is less with the divergent procedure.
All questions will have been with respect to the existing procedure; notwithstanding that, the principles are still the same and apply equally to both procedures.
Jim
Work is progressing on the definition of an alternative ARA procedure (taking advantage of SBAS and providing omni-directional, offset, automatic approaches and eliminating necessity for a turn at the OIP) - a report will be issued quite soon.
JimL - at the risk of sounding too cynical, it seems there may be a risk of intellectualising this problem and ending up with another 10,000 word diatribe within which may be hidden a couple of nuggets of useful facts and advice.
Rather than approaching this from a perspective that there is a safety problem that needs addressing, the CAA seems happy to take the opportunity of hijacking some research done by someone with a completely different agenda and using it in another study which may not be applicable to present ops.
Is the answer really going to be more manoeuvering at low level, at night or in poor weather whilst trying to land - hardly seems like progress?
Rather than approaching this from a perspective that there is a safety problem that needs addressing, the CAA seems happy to take the opportunity of hijacking some research done by someone with a completely different agenda and using it in another study which may not be applicable to present ops.
Is the answer really going to be more manoeuvering at low level, at night or in poor weather whilst trying to land - hardly seems like progress?
More manoeuvring with Offset procedure
Jim
Do you have a diagram you could post showing the difference in visual manoeuvring required between the divergent and offset procedures? I could of course draw it for myself but 1) as you know, I am too lazy and 2) it might be interesting for others to see.
Is there a difference approaching MAPT as to where to look to see the installation, and would this affect the probability of seeing the installation and/or the ability of PNF to monitor the instruments?
roundwego, I think there have been few if any reported incidents on ARAs, however a night ARA to minima is a fairly rare event so we shouldn't be complacent (and not sure that reporting culture is particularly good at reporting what might be seen as "own fault" events)
HC
Do you have a diagram you could post showing the difference in visual manoeuvring required between the divergent and offset procedures? I could of course draw it for myself but 1) as you know, I am too lazy and 2) it might be interesting for others to see.
Is there a difference approaching MAPT as to where to look to see the installation, and would this affect the probability of seeing the installation and/or the ability of PNF to monitor the instruments?
roundwego, I think there have been few if any reported incidents on ARAs, however a night ARA to minima is a fairly rare event so we shouldn't be complacent (and not sure that reporting culture is particularly good at reporting what might be seen as "own fault" events)
HC
Crab - I PM'd; if there is a need, I will post answering your questions. At the moment I see no reason to enter into a debate about the quality of the risk assessment.
Before I attempt to address Helicomparator's point, I have to admit that I had fooled myself into thinking that there would be a major discrepancy in the relative position of the rig (in the FOV) between the 'offset' and 'divergent' approaches - my intuition was wrong.
It is difficult to do any maths because the 'offset' distances are not yet established; however we can make assumptions which will not be wildly in error. If a 10 degree heading change is made at the OIP (1.5nm) the divergence would take us about 490m abeam the rig (we don't actually get to that point because the procedure always requires a turning missed approach at 0.75nm). We can assume that this is the miss distance for the 'offset' procedure - if it is further than this, the differences increase.
At DR/MAPt (0.75nm = 1390m from the rig) with the divergent procedure, the rig will appear at just over 20 degrees to one side (10 degrees relative from the rig + the 10 degree of the divergent heading) and the track-offset will be 250m. With the 'offset' procedure the rig will be seen at (just over) 20 degrees (all of it relative to the rig) and the offset would be 490m.
If it was necessary to position the aircraft back onto the into-wind track, the 'offset' procedure would take more manoeuvring than the divergent.
With a DR/MAPt of 0.5nm (926m from the rig) the position of the rig in the FOV would be respectively 31 v 32 degrees and the track-offset would be 338m v 490m; the 'divergent' would be 20 degrees out of wind and the 'offset' 30 degrees. For both procedures the position of the rig in the FOV (now possibly to one side of the windscreen), the additional manoeuvring, plus the reduced distance for deceleration raises issues.
If you want to see this in diagramatic form draw a rectangle of sides 2778 and 490 with a line (from the OIP) joining the diagonals; put the rig at one end of the 2778 line and the OIP at the other; take two arcs of length 1390 (0.75nm) and 926 (0.5nm) from the rig and intersect the diagonal and the outer line; enter the offset distances/angles I have provided.
Jim
Before I attempt to address Helicomparator's point, I have to admit that I had fooled myself into thinking that there would be a major discrepancy in the relative position of the rig (in the FOV) between the 'offset' and 'divergent' approaches - my intuition was wrong.
It is difficult to do any maths because the 'offset' distances are not yet established; however we can make assumptions which will not be wildly in error. If a 10 degree heading change is made at the OIP (1.5nm) the divergence would take us about 490m abeam the rig (we don't actually get to that point because the procedure always requires a turning missed approach at 0.75nm). We can assume that this is the miss distance for the 'offset' procedure - if it is further than this, the differences increase.
At DR/MAPt (0.75nm = 1390m from the rig) with the divergent procedure, the rig will appear at just over 20 degrees to one side (10 degrees relative from the rig + the 10 degree of the divergent heading) and the track-offset will be 250m. With the 'offset' procedure the rig will be seen at (just over) 20 degrees (all of it relative to the rig) and the offset would be 490m.
If it was necessary to position the aircraft back onto the into-wind track, the 'offset' procedure would take more manoeuvring than the divergent.
With a DR/MAPt of 0.5nm (926m from the rig) the position of the rig in the FOV would be respectively 31 v 32 degrees and the track-offset would be 338m v 490m; the 'divergent' would be 20 degrees out of wind and the 'offset' 30 degrees. For both procedures the position of the rig in the FOV (now possibly to one side of the windscreen), the additional manoeuvring, plus the reduced distance for deceleration raises issues.
If you want to see this in diagramatic form draw a rectangle of sides 2778 and 490 with a line (from the OIP) joining the diagonals; put the rig at one end of the 2778 line and the OIP at the other; take two arcs of length 1390 (0.75nm) and 926 (0.5nm) from the rig and intersect the diagonal and the outer line; enter the offset distances/angles I have provided.
Jim
Last edited by JimL; 17th Aug 2009 at 15:11.
Thanks Jim, yes I can see that the chosen lateral offset makes a big difference. Since the approach is to be flown coupled (and therefore drift is less of an issue) do you think we should fly the approach out of wind, so that at MAPt/DR we are directly downwind of the installation?
HC
HC
Jim, I don't see the slides, but am famliar with the European and US work being done, and I think the fundamental anomoly in your assumption is that for the diverging procedure the WX RADAR is the primary means of determining DR, whereas for the offset procedure it's the GNSS. The latter will therefore place you at a a more obtuse angle - using the proposed procedures with virtually abeam MAPts. Of course, for any given physical position - relative to the rig - the diverging procedure will require greater manouevering to resturn to the final approach track.
I think HC has a good point, and even now with the 'traditional ARA' the use of coupling, and GNSS to assist the process, raises interesting points on choice of approach direction and interpretation of achieved/desired offset e.g. use of the track-made-good bug (diamond in the 225, 'doughnut' in the 92) versus radar target orientation on the screen.
The work I'm familiar with taking place in the US will, undoubtedly , offer a huge step forward in safety for routine night operations - even though it's being developed for the instrument approach - and will allow the aircraft to be manouevred at low speed in a fully coupled state to the commital point (virtually.)
I think HC has a good point, and even now with the 'traditional ARA' the use of coupling, and GNSS to assist the process, raises interesting points on choice of approach direction and interpretation of achieved/desired offset e.g. use of the track-made-good bug (diamond in the 225, 'doughnut' in the 92) versus radar target orientation on the screen.
The work I'm familiar with taking place in the US will, undoubtedly , offer a huge step forward in safety for routine night operations - even though it's being developed for the instrument approach - and will allow the aircraft to be manouevred at low speed in a fully coupled state to the commital point (virtually.)
Thanks for the PM JIm - situation clarified
212man - I have assumed accurate positioning at the DR/MAPt in order to provide the diagram; this always produces less manoeuvring for the divergent procedure (if attempting to regain the into-wind track) for obvious reasons.
The work on the revised ARA obviously took account of the FAA system which provided fixed tracks - this was also the basis of Norwegian modification (provide to eliminate the turning missed approach in a tight obstacle environment). Such procedures are probably too restrictive as they rarely provide more than a small number of fixed paths for any location. On the plus side, the offset distance can be calculated with some accuracy and meet international standards (DOC 8168).
I must say I was surprised when discovering that the revised procedure would be omni-directional; however this does introduce issues as, unless there is accurate measurement and representation of each platform's environment in the data-base, it will have to rely upon a single distance based upon the worst case (for each location). This is one effect of an offset procedure with a standard (straight ahead) missed approach (but deterministic and safer than a turning missed approach).
HC - I arrived at the same conclusion yesterday when drawing the diagram.
The main hazards of any non-precision procedure are not in the instrument segments but during the level segment and at the DR/MAPt (that is why there has been a move towards CDFA - see my earlier post on this page - to the point where non-CDFA procedures are penalised in the approach minina under the latest revisions of EU-OPS). It has been established for a number of years that the most critical point of any procedure occurs at the MAPt and the studies (CAA and FSF ALAR) provide substantial evidence of of this.
It is noteworthy that the studies only considered straight-in approaches; the ARA has the added difficulty that, in addition to acquiring the target, the pilot has to further manoeuvre the aircraft to the landing phase. Whatever profile is produced, it will not alter the basis of the procedure that there has to be an offset because the obstacle to be avoided in the missed approach is also the landing site.
As has been recognised for some time, once visual reference (in accordance with the requirements) has been established, landing into wind will require an S-turn to regain the into-wind track followed by a deceleration and let down. If the DR/MAPt is at 0.75nm, this will not result in a tight manoeuvre (less for the 'divergent' than the 'offset'); if at 0.5nm the whole procedure becomes squeezed because of the more acute angle and the reduced space in which the manoeuvre is performed (and this on top of the additional complexity of acquisition of a target 30 degrees to one side).
The revised ARA procedure appears to take an 'input' of the proposed track (we assume that this will be the into-wind track) and then constructs the complete profile (vertical and horizontal). There is no reason then why the profile could not be constructed such that the DR/MAPt is downwind of the landing site. This would also assist in the acquisition of the target as the drift angle would put the target closer to the centre of the windscreen. Such a procedure would then only require a single and maximum turn of 30 degrees (less if the DR/MAPt is at 0.75nm) to put the aircraft on the final track.
Regardless of any of this, the radar will still be necessary to ensure that there are no obstacles in the approach path - this might be complicated with any complex approach path computations. I believe that there are assumptions that the radar will not be necessary and other methods can be used; I do not subscribe to that contention for the same reason that I believe that use of the 'E' function of the EGPWS is flawed offshore.
Jim
The work on the revised ARA obviously took account of the FAA system which provided fixed tracks - this was also the basis of Norwegian modification (provide to eliminate the turning missed approach in a tight obstacle environment). Such procedures are probably too restrictive as they rarely provide more than a small number of fixed paths for any location. On the plus side, the offset distance can be calculated with some accuracy and meet international standards (DOC 8168).
I must say I was surprised when discovering that the revised procedure would be omni-directional; however this does introduce issues as, unless there is accurate measurement and representation of each platform's environment in the data-base, it will have to rely upon a single distance based upon the worst case (for each location). This is one effect of an offset procedure with a standard (straight ahead) missed approach (but deterministic and safer than a turning missed approach).
HC - I arrived at the same conclusion yesterday when drawing the diagram.
The main hazards of any non-precision procedure are not in the instrument segments but during the level segment and at the DR/MAPt (that is why there has been a move towards CDFA - see my earlier post on this page - to the point where non-CDFA procedures are penalised in the approach minina under the latest revisions of EU-OPS). It has been established for a number of years that the most critical point of any procedure occurs at the MAPt and the studies (CAA and FSF ALAR) provide substantial evidence of of this.
It is noteworthy that the studies only considered straight-in approaches; the ARA has the added difficulty that, in addition to acquiring the target, the pilot has to further manoeuvre the aircraft to the landing phase. Whatever profile is produced, it will not alter the basis of the procedure that there has to be an offset because the obstacle to be avoided in the missed approach is also the landing site.
As has been recognised for some time, once visual reference (in accordance with the requirements) has been established, landing into wind will require an S-turn to regain the into-wind track followed by a deceleration and let down. If the DR/MAPt is at 0.75nm, this will not result in a tight manoeuvre (less for the 'divergent' than the 'offset'); if at 0.5nm the whole procedure becomes squeezed because of the more acute angle and the reduced space in which the manoeuvre is performed (and this on top of the additional complexity of acquisition of a target 30 degrees to one side).
The revised ARA procedure appears to take an 'input' of the proposed track (we assume that this will be the into-wind track) and then constructs the complete profile (vertical and horizontal). There is no reason then why the profile could not be constructed such that the DR/MAPt is downwind of the landing site. This would also assist in the acquisition of the target as the drift angle would put the target closer to the centre of the windscreen. Such a procedure would then only require a single and maximum turn of 30 degrees (less if the DR/MAPt is at 0.75nm) to put the aircraft on the final track.
Regardless of any of this, the radar will still be necessary to ensure that there are no obstacles in the approach path - this might be complicated with any complex approach path computations. I believe that there are assumptions that the radar will not be necessary and other methods can be used; I do not subscribe to that contention for the same reason that I believe that use of the 'E' function of the EGPWS is flawed offshore.
Jim