New Jepps plates - a question?
Jim,
if you commence the MAP before the MAPt then clearly you must continue the azimuth guidance to the MAPt before commencing any turns. This is not news though, and is equally applicable to an ILS with a MAP before DA.
Yes, there are MAPts beyond the threshold - many non-DME approaches will have the MAPt at the navaid - NDB or VOR - which may well be somewhere on the aerodrome.
if you commence the MAP before the MAPt then clearly you must continue the azimuth guidance to the MAPt before commencing any turns. This is not news though, and is equally applicable to an ILS with a MAP before DA.
Yes, there are MAPts beyond the threshold - many non-DME approaches will have the MAPt at the navaid - NDB or VOR - which may well be somewhere on the aerodrome.
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This is from PansOps 8168 Ammend 14...Note the differences in calculating the DA vs MDA from the OCA.
(there are many thread regarding MDA/DA in the tech forum)
(there are many thread regarding MDA/DA in the tech forum)
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212 man
Surely there are two distinct points here? The first is whether or not CDFA procedures are “mandated” for helicopters - surely they are not since all of the guidance / regulation appears in FW material (e.g Eu-Ops, from which helicopters are expressly exempted).
The second point is a discussion over whether or not it is a good, better or worse procedure for helicopters. That isn’t a straightforward answer, since it doesn’t aid older helicopters at all, but just adds height to the minima (the CDFA ‘DA’ is always higher than an MDA(H)).
Your point about what to do when the missed approach point is past the threshold is surely moot? This is really just the official point from which to start the Go Around - I certainly wouldn’t expect to try to recover from there BUT I will have probably been flying a level segment at the minima for some time prior to the MAPt so would expect to commence a visual approach from somewhere before the MAPt - possibly from a similar geographic position that the CDFA would have put you at, but from a lower altitude.
I just don’t think we have the same problems as the FW guys with the ‘level ‘ bit of the current procedures, particularly at the sort of airspeeds you can elect to fly the approach if it looks marginal.
We have had no indications at all from the Authority here that we are expected to use CCDFA procedures.
The quickest answer to Geoffers problem is surely to switch to Aerads?!
Surely there are two distinct points here? The first is whether or not CDFA procedures are “mandated” for helicopters - surely they are not since all of the guidance / regulation appears in FW material (e.g Eu-Ops, from which helicopters are expressly exempted).
The second point is a discussion over whether or not it is a good, better or worse procedure for helicopters. That isn’t a straightforward answer, since it doesn’t aid older helicopters at all, but just adds height to the minima (the CDFA ‘DA’ is always higher than an MDA(H)).
Your point about what to do when the missed approach point is past the threshold is surely moot? This is really just the official point from which to start the Go Around - I certainly wouldn’t expect to try to recover from there BUT I will have probably been flying a level segment at the minima for some time prior to the MAPt so would expect to commence a visual approach from somewhere before the MAPt - possibly from a similar geographic position that the CDFA would have put you at, but from a lower altitude.
I just don’t think we have the same problems as the FW guys with the ‘level ‘ bit of the current procedures, particularly at the sort of airspeeds you can elect to fly the approach if it looks marginal.
We have had no indications at all from the Authority here that we are expected to use CCDFA procedures.
The quickest answer to Geoffers problem is surely to switch to Aerads?!
There is currently a debate going on about whether to encourage helicopters to use CDFA procedures; as someone has already said, in EU-OPS the penalty for not flying a CDFA approach is an increased RVR (and this can be waived by the Authority). A similar penalty is likely to apply to EASA OPS.
It is not clear (to me at least) where WIGY' has obtained the information that the DA(H) will always be higher than the MDA(H) - certainly the DA(H) calculation in EU-OPS Appendix 1 (New) to OPS 1.430 appears to be the same for a CAT 1 (system minima 200ft) approach and CDFA with the exception of the 'system minima in Table 3' (which ranges from 250ft - for a localiser with or without DME, to 350ft for a vanilla NDB; with an RNAV/LNAV at 300ft).
As the level segment of an MDA(H) approach can be flown in IMC it is likely that the minimum speed will be governed by the Flight Manual (Vmini). Some gains here though as approach speeds are between 70kts and 90kts - lower than for our heavy fixed wing brethren.
There has been representation to EASA not to mandate CDFA (with its addition to RVR) for helicopter and they are unlikely to press the issue. (As was previously stated, this could have had an effect on the ARA (DH below system minima) and complicate Point in Space procedures.)
There is likely to be encouragement from the Authority (EASA) to move to CDFA for airfield procedures as there is no doubt that it does improve safety (as has been seen in the ALARP work).
Moving to AERAD only postpones the inevitable.
Jim
It is not clear (to me at least) where WIGY' has obtained the information that the DA(H) will always be higher than the MDA(H) - certainly the DA(H) calculation in EU-OPS Appendix 1 (New) to OPS 1.430 appears to be the same for a CAT 1 (system minima 200ft) approach and CDFA with the exception of the 'system minima in Table 3' (which ranges from 250ft - for a localiser with or without DME, to 350ft for a vanilla NDB; with an RNAV/LNAV at 300ft).
As the level segment of an MDA(H) approach can be flown in IMC it is likely that the minimum speed will be governed by the Flight Manual (Vmini). Some gains here though as approach speeds are between 70kts and 90kts - lower than for our heavy fixed wing brethren.
There has been representation to EASA not to mandate CDFA (with its addition to RVR) for helicopter and they are unlikely to press the issue. (As was previously stated, this could have had an effect on the ARA (DH below system minima) and complicate Point in Space procedures.)
There is likely to be encouragement from the Authority (EASA) to move to CDFA for airfield procedures as there is no doubt that it does improve safety (as has been seen in the ALARP work).
Moving to AERAD only postpones the inevitable.
Jim
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Jim,
I would concur with you, with the criteria basically being massage FW procedure. The tables, speeds, and parameters just dont fit..a helo is not the same as a CAT A aircraft, Vmini is a major issue, and a reliance on PinS procedures.
When the .42B criteria came out, I was hoping for industry feedback, it just appears it was largely ignored...
I would concur with you, with the criteria basically being massage FW procedure. The tables, speeds, and parameters just dont fit..a helo is not the same as a CAT A aircraft, Vmini is a major issue, and a reliance on PinS procedures.
When the .42B criteria came out, I was hoping for industry feedback, it just appears it was largely ignored...
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Just a couple of points:
1. Continuous descent approaches are not yet mandatory for helo ops. There are procedures in Europe, however, where there is no option, in that only a DA is published for the non-precision approaches. Even though they're not mandatory for helos, clearly we may need to fly them and thus need to know how they work.
2. Several states have simply relabelled MDAs as DAs without any thought as to why there's a difference. However, just because there may not be a difference between the new DA and the previous MDA does not mean that there is an error; although the two are calculated differently there's no reason that a DA should necessarily be higher than the MDA it replaces.
3. The MAPt is simply the LATEST point by which you must commence a go-around; you're quite free to go around earlier. In fact, if you follow the letter of the 1173/1174 forms precisely (LST/LPC) they say "NPA down to the MDA" and "go-around on reaching the MDA", thus there is no need for a level segment for licensing purposes and the pilot (unless briefed otherwise) should start the MAP on reaching minima.
4. Unless the plate specifically says that you must continue to the MAPt before commencing the go-around then you can turn as soon as you like since the area in which obstacles are considered includes those as far back as the FAF. I'd not advise this, however.
5. Continuous descent non-precision approaches with a DA are still NON-precision; they don't become precision approaches simply by the change from an MDA to a DA.
6. Some aircraft have a Pressure Error Correction (PEC) which must be added to the minimum altitude for precision approaches since the pitot lags and over-reads in descent. For non-precision approaches this has been allowed to be ignored since there is the level segment during which the baralt will stabilise, but continuous descent profile descents clearly have the aircraft still descending at the DA, so although the law doesn't require it, the sensible pilot will add the PEC to non-precision continuous descent procedure minima.
I don't log on to PPRuNe very often so please direct questions and comments to me at gCAP (gCAP Main Page).
1. Continuous descent approaches are not yet mandatory for helo ops. There are procedures in Europe, however, where there is no option, in that only a DA is published for the non-precision approaches. Even though they're not mandatory for helos, clearly we may need to fly them and thus need to know how they work.
2. Several states have simply relabelled MDAs as DAs without any thought as to why there's a difference. However, just because there may not be a difference between the new DA and the previous MDA does not mean that there is an error; although the two are calculated differently there's no reason that a DA should necessarily be higher than the MDA it replaces.
3. The MAPt is simply the LATEST point by which you must commence a go-around; you're quite free to go around earlier. In fact, if you follow the letter of the 1173/1174 forms precisely (LST/LPC) they say "NPA down to the MDA" and "go-around on reaching the MDA", thus there is no need for a level segment for licensing purposes and the pilot (unless briefed otherwise) should start the MAP on reaching minima.
4. Unless the plate specifically says that you must continue to the MAPt before commencing the go-around then you can turn as soon as you like since the area in which obstacles are considered includes those as far back as the FAF. I'd not advise this, however.
5. Continuous descent non-precision approaches with a DA are still NON-precision; they don't become precision approaches simply by the change from an MDA to a DA.
6. Some aircraft have a Pressure Error Correction (PEC) which must be added to the minimum altitude for precision approaches since the pitot lags and over-reads in descent. For non-precision approaches this has been allowed to be ignored since there is the level segment during which the baralt will stabilise, but continuous descent profile descents clearly have the aircraft still descending at the DA, so although the law doesn't require it, the sensible pilot will add the PEC to non-precision continuous descent procedure minima.
I don't log on to PPRuNe very often so please direct questions and comments to me at gCAP (gCAP Main Page).
