Determination of DA(H)

[shazapis]

Hello,

I am trying to find any regulatory reference to the need to add 50 feet to the MDA(H) of an NPA in order to determine the DA(H) for the CDFA technique.

I have had no luck thus far, although everybody tells me (referencing their ops manuals though, not a regulation) that this is indeed a requirement when flying a NPA using CDFA.

Any assistance will be greatly appreciated

Regards,

Spiros Chazapis
Athens, Greece

[BOAC]

You must not descend below MDA so you need to add something! Whether it is 50/30/or???.

[shazapis]

Hello,

Yes I know it makes perfect sense from an operational standpoint.
What I am looking for though is a specific reference in a regulatory document (by any source, FAA, ICAO, EASA, whatever).

Spiros Chazapis
Athens, Greece

[BOAC]

The 'regulatory document' says you must not descend below MDA. Your company SOPs will then tell you what you need to add - it's er - common-sense?

[shazapis]

Hello again,

No, I have been told that there is a specific requirement, originating from a regulation, that a minimum of 50 feet MUST be added to the published MDA(H), plus any additional SOPs/type specific/operator specific/whatever factor.

Actually, I have seen this with my own eyes but, alas, I can't seem to find it in my (large and messy) document library.

Please realize I am not making this up and I do have operational experience (I am a RW pilot). Also, forgive me if occasionally some of the things I write make no sense (not being a native English speaker can be a pain)...

Spiros Chazapis
Athens, Greece

[punk666]

Its an EU-Ops requirement to add 50ft to the MDA.

As mentioned above, you cannot decend below the MDA so when you start your go-around the aircraft will still decend around 30-40 feet before it will start to climb away...this 50 feet is a buffer.

With the DA(H) its the latest altitude you can start a go-around or I should say make the decision to go-around.

Make sure you read the plates as some NPA now use DA(H) instead of MDA.

[shazapis]

Hello,

Thank very much for the reply. It is exactly what I've been looking for.
Do you know if EU-OPS is available online ? (I am military and we do not have immediate access to EU-OPS)

By the way, do you know if there is a way to determine (ideally in the cockpit) whether a procedure is published by the authority with a DA(H) (and therefore already includes the 50 ft - am I right?) or if it is just a chart conversion by Jepessen or some other publisher (they specifically state that they do not add anything to MDA(H) in order to determine the DA(H).

Regards,

Spiros Chazapis
Athens, Greece

[BOAC]

Shaza - your English is fine! In other threads here about this some have said that their company says add 30 or 40 feet depending on type/height loss in the g/a..

punk - do you have a para reference for that?

[reynoldsno1]

Make sure you read the plates as some NPA now use DA(H) instead of MDA.
These are LNAV/VNAV APV procedures, and the DA is determined using methodology similar to that used for ILS - it is not just a case of adding 50ft to an MDA for these procedures.

[Nightrider]

Late in 2008 Jeppesen placed a Notam in their manuals to explain the procedure, the changes from MDA(H) to DA(H) and the requirements an operator has to follow. Not sure if it is still in place.

[rudderrudderrat]

Hi Nightrider,

Was this the explanation from Jeppesen you referred to?

jeppesen.com/download/aopa/dec99aopa.pdf (http://www.jeppesen.com/download/aopa/dec99aopa.pdf)

[Checkboard]

For approaches, the surveyor surveys the area and establishes an Obstacle Clearance Height (OCH) for the approach.

The regulator then determines an appropriate overall System Minima for each type of approach - this is the minimum altitude that an operator may authorise their crews to descend to on that type of approach.

The operator then looks at their training program, equipment and experience in an area of operations and determines the authorised minima for each approach (which in the vast majority of cases is the same as the greater of the system minima/OCH - and this is the number Jeppesen place on their charts, unless you have an operator-specific chart).

The Commander then sets the minimum for the approach on the day. This is the charted number in the vast majority of cases, but the commander has the right to say (for example) "On today's approach, with this weather, this terrain and these MELs, we shall add 200 feet to the published minima before making a missed approach and diverting."

From EU-OPS (available on-line at: EU-OPS (http://redirectingat.com/?id=42X487496&xs=1&url=http%3A%2F%2Feur-lex.europa.eu%2FLexUriServ%2FLexUriServ.do%3Furi%3DOJ%3AL%3A 2006%3A377%3A0001%3A0175%3AEN%3APDF&sref=http%3A%2F%2Fwww.pprune.org%2Fquestions%2F339604-jar-ops-eu-ops-documents-online.html)):

Appendix 1 (Old) to OPS 1.430
Aerodrome operating minima

2. Minimum descent height. An operator must ensure that the minimum descent height for a non-precision approach is not lower than either:

(i) The OCH/OCL for the category of aeroplane; or

(ii) The system minimum.

3. Visual reference. A pilot may not continue an approach below MDA/MDH unless at least one of the following visual references for the intended runway is distinctly visible and identifiable to the pilot:

(i) elements of the approach light system;

(ii) the threshold;

(iii) the threshold markings;

(iv) the threshold lights;

(v) the threshold identification lights;

(vi) the visual glide slope indicator;

(vii) the touchdown zone or touchdown zone markings;

(viii) the touchdown zone lights;

(ix) runway edge lights; or

(x) other visual references accepted by the Authority.

The 50' addition to the MDA referred to above is applied by the operator (and is a pseudo standard) as part of step three above. The regulatory requirement is both to "not continue an approach below" AND an "operator must ensure that the minimum descent height for a non-precision approach is not lower than" (which is why most operators specify 50' addition) however there is no regulatory reference which specifies that "50 feet" shall be used.

You are, of course, legally bound to follow your OPS manual procedures.

[Nightrider]

rudderrudderrat no, it was a notam.

[rudderrudderrat]

Hi,

The NOTAM I seem to remember read like something like this.
(copied and pasted from the link (11) posted above.)

"Using the MDA as a DA
There are many aircraft today that are equipped with vertical navigation equipment and are capable and authorized to fly the computed descent angle on non-precision approaches. Because of this capability and the airlines’ desire to use more of the capability in their FMSs, the FAA issued a Joint flight Standards handbook bulletin for Air Transportation (HBAT) and General Aviation (HBGA). The Bulletin number is HBAT 99-08 and HBGA 99-12 and is applicable to operators under FAR 121, 125, 129, or 135.

The profile view with KENDO as the FAF shows a slightly different depiction of the descent angle. Instead of a dotted line, there is a dashed line from the FAF down to the MDA. Note that the dashed line stops at the MDA and is followed by a small arrow that curves up at the MDA. This shows that the MDA can be used as a DA(H).

Once the statement is made that the MDA can be used as a DA(H), a lot of explaining is necessary. And a lot of conditions must be met.

There is a small ball flag with the number “1” at the bottom of the dashed line. The ball flag refers to the note that states, “Only authorized operators may use VNAV DA(H) in lieu of MDA(H).” First, special approval from the FAA is necessary for each operator to gain this new benefit. And - the approval is only for certain airplanes used by the operator. And the big “IF.” The MDA may be used as a DA only if there has been a visual segment obstacle assessment made for the straight-in landing runway. The FAA has stated that there has been an obstacle assessment when the runway has a VASI or PAPI as a visual guidance system indicator, an electronic glideslope, or an RNAV approach published with a decision altitude.

Since an obstacle assessment has been made, the FAA has authorized the DA since it is assumed that a momentary descent will be made below the DA during the execution of a missed approach."

[Nightrider]

My memory failed me, it was a Briefing Bulletin, sorry. Here is the text, found after digging a lot:
AERODROME OPERATING MINIMUMS ACCORDING TO EU-OPS 1
General Information
The European Union published the . 2nd Amendment of EU-OPS 1 (Annex III to Regulation 3922/91) (http://eur-lex.europa.eu/JOIndex.do?ihmlang=en)
This EU-OPS 1 is the replacement of JAR-OPS 1 and contains a new method to determine Aerodrome Operating
Minimums (AOM). The new method will become the European Standard on 16 July 2011 at the latest.
According to ICAO Doc 9365-AN910 (Manual of All Weather Operations) and Annex 6 to the Convention on International Civil Aviation it is the operator’s responsibility to establish Aerodrome Operating Minimums which need to be approved by the responsible authority.
The Appendix 1 (new) to OPS 1.430 describes the method which has to be used by all European Operators and within the European Union (EU).
Jeppesen will support your operations by replacing the current JAR-OPS AOM with the new Standard. Due to the huge number of airports (1000+) and procedures (5000+) the conversion could only be done on a step by step basis.
It is our intent to have all procedures revised to the new Standard AOM by 16 July 2011 for all airports within
– European Union member states,
– European Aviation Safety Agency (EASA) member states,
– Joint Aviation Authorities (JAA) member states and
– for other states where the currently used JAR-OPS AOM will be replaced.
In May 2008 we asked commercial operators about their plans for this EU-OPS implementation. The following items are directly related to the results of that survey:
a. All non-precision approaches will be reviewed to show CDFA (Continuous Descent Final Approach) profile and minimums.
b. In case of CDFA only, a DA(H) is shown instead of the previously published MDA(H). The missed approach point is still shown according to state source but the missed approach initiation arrow is moved to the point where the DA(H) is reached.
c. Jeppesen charted AOM do not include an add-on when current MDA(H) is replaced by DA(H). Pilots are reminded to check their operator’s Flight Operations Manual or similar documents whether they have to apply an add-on or not.
d. For CDFA profiles, Jeppesen will show DME vs altitude bands, distance vs altitude bands or timing vs altitude tables. If not provided by the State source those altitudes will be calculated by Jeppesen.
e. Non-CDFA profiles and minimums will be shown in exceptional cases only and may be combined with CDFA
profiles and minimums.
f. For CAT I operations with full approach light system (FALS) Jeppesen will include RVR values below 750m together with the higher values. Pilots are reminded to check their operator’s Flight Operations Manual or similar documents to fulfill the requirements for using the lower RVR values.
g. Lower than standard CAT I minimums are charted on request on customer tailored charts.
h. Other than standard CAT II minimums will be charted if the procedure is approved for such operations by the state of the airport.
i. Circling minimums must not be lower than the minimums of preceding instrument approach procedure. If circling MDA(H) and/or visibility must be raised due to higher straight-in values, only one set of circling minimums is shown which relates to the highest straight-in minimums.
Legend and ATC Pages
Jeppesen is currently reviewing the final version of this EU-OPS to replace the current ATC-601 (JAA AOM)
pages with a summarization of the new EU-OPS Aerodrome Operating Minimums.
In addition we will update the current Introduction 171 – 173 (JAR-OPS 1 AOM) pages to explain how the new minimums and the CDFA profiles are depicted on Jeppesen charts.
Conversion Plan
The publication of the new Standard of AOM will be done along with normal chart revision activity. It is planned
to convert all procedures of an affected airport at the same time.
We will create special minimums pages, numbered 10-9S (similar to current 10-9X JAR-OPS pages), as an interim solution.
Jeppesen will maintain or create JAR-OPS 1 minimums pages on customer request only.
Please contact your Jeppesen customer service representative for any special requirements, such as airline tailored minimums, airborne equipment considerations or your conversion priorities.
Charts with JAR-OPS label
The JAR-OPS label on Jeppesen approach and airport charts indicates that the minimums correspond to the rules described in Appendix 1 (old) to OPS 1.430 of the EU-OPS 1.
Future Outlook
The FAA will also publish new minimums which will be harmonized with the EU ones.
Jeppesen’s intention is to replace the current ECOMS and JAR-OPS Aerodrome Operating Minimums with the future harmonized version on a world-wide basis.

[savi]

Hello,

When you fly NPA as CDFA, you may use MDA/H as the DA/H with no height add-on.

(EU-OPS Operator - the minima calculated in accordance with Appendix 1 (New))


AIRBUS - Flight Operations Briefing Notes
From Non-Precision to Precision-like Approaches

The nature of the minima’s, MDA(H) or DA(H):
The MDA(H) being a minimum descent altitude, no altitude loss below the MDA(H) is allowed during the approach and go-around; this implies to either:
− Level-off at the MDA(H) - step-down / dive-and-drive technique - until visual references are acquired:
− Initiate the go-around above the MDA(H) - constant descent-angle technique - if no visual references are acquired, in order not to “duck under” the MDA(H).
This is obviously not required when the applicable minima is a DA(H), which is a decision altitude; if no visual references are acquired when reaching the DA(H), a go-around must be initiated at DA(H)

[BOAC]

you may use MDA/H as the DA/H with no height add-on. - no. Read the note again!

Initiate the go-around above the MDA(H) - constant descent-angle technique - if no visual references are acquired, in order not to “duck under” the MDA(H).

[411A]

Quote:
Initiate the go-around above the MDA(H) - constant descent-angle technique - if no visual references are acquired, in order not to “duck under” the MDA(H).


Much consternation, it seems.:rolleyes:
All this can be avoided, of course, if one uses a sensible alternative, dive/drive....IE, fly a short level segment, from which a go-around does not require adding an altitude 'buffer'.

It would appear that certain companies/regulatory authorites have made all this much more complicated than it actually needs to be.

No surprise there.:ooh:
After all, how else would they justify their salaries?:hmm:

[BOAC]

Seems to be an American thing 411? From Jeppesen:

There are many aircraft today that are
equipped with vertical navigation equipment
and are capable and authorized to fly the
computed descent angle on non-precision
approaches. Because of this capability and
the airlines’ desire to use more of the
capability in their FMSs, the FAA issued a Joint
flight Standards handbook bulletin for Air
Transportation (HBAT) and General Aviation
(HBGA). The Bulletin number is HBAT 99-08
and HBGA 99-12 and is applicable to
operators under FAR 121, 125, 129, or 135.My Bold

and

Most aviation authorities and industry leaders
have recognized the safety benefits that will
be gained by reducing the number of nonprecision
approaches that don’t have vertical
guidance. The addition of vertical guidance
should help to reduce the number of CFIT
(controlled flight into terrain) accidents.
Recently, the NTSB has recommended that
aircraft with onboard capabilities for vertical
guidance should be required to use them
during non-precision approaches. They have
also recommended that within 10 years all
non-precision approaches approved for air
carriers should incorporate constant-angle
descents with vertical guidance from
onboard systems.Which FAR do you fly under? Have you seen the bulletin?

[EMIT]

411A, if you want to fly level at MDA, how high above MDA do you have to start levelling off, in order not to sag through it, would about 50 ft be a nice estimate?
In that way the margin discussion turns into a storm in a bowl of dust.

The 50 ft have just become a sort of industry standard figure for most types (not all, e.g. the famous MD-11 does not require that margin, lightning fast acceleration on Go Around apparently)

Am not gonna chastise you for the D/D technique, it's just that the trend in regulation and in many outfits is moving away from it and today's avionics make it possible to achieve good results with the "artificial glidepath" technique, an accurate present position is the basic element that makes it possible (yes, some aircraft types had that already eons ago).

[deefer dog]

I tend to agree with 411 on this one!

For some time I have been wondering why we are being encouraged to use the CDA approach method simply because we now have the kit to do it accuartely. It seemed to me early on that such an approach, when likely conducted to minimums, gives little time for crews to look out and have any chance of getting the required visual cues, especially if MDA(H) is likely to coincide with what will (in effect be) a MAP?

Provided that one adheres strictly to the appropriate step down levels, what is wrong with aiming the descent to conclude at a distance that permits level off at the MDA(H), followed by level flight of a short duration?

Provided one doesn't bust it, the little extra time at the minimum permitted level is likely to give one a better chance of making a successful approach if the conditions permit.

[savi]

To BOAC

... read all text again

The nature of the minima’s, MDA(H) or DA(H):

Part 1 - minimum is MDA(H) - CDFA or non CDFA
The MDA(H) being a minimum descent altitude, no altitude loss below the MDA(H) is allowed during the approach and go-around; this implies to either:
− Level-off at the MDA(H) - step-down / dive-and-drive technique - until visual references are acquired:
− Initiate the go-around above the MDA(H) - constant descent-angle technique - if no visual references are acquired, in order not to “duck under” the MDA(H).

Part 2 - minimum is DA(H) - only CDFA
This is obviously not required when the applicable minima is a DA(H), which is a decision altitude; if no visual references are acquired when reaching the DA(H), a go-around must be initiated at DA(H)

... and more info from JAA

Issues related to DA/H and MDA/H

The application of the CDFA technique requires all NPA operations, to be flown with a decision altitude/height (DA/H). When determining the applicable DA/H, the operator must take account of the missed approach point (MAPt) and the minimum descent altitude/height (MDA/H). While it is quite clear that a missed approach must be initiated not later than at the MAPt, the question of MDA/H is a different matter. Quite a few operators use MDA/H as the DA/H with no height add-on; in fact this is the case with a majority of the largest European operators. This modus operandi has
raised concern that the unavoidable height loss below the MDA/H during a go-around might introduce a safety risk, even if the height loss can be minimised by the use of appropriate operational procedures (call-outs, high degree of on-speed/on-path discipline, training). In order to evaluate the safety of the use of MDA/H as DA/H, the AWOSG has compared the obstacle protection for this type of approach with the obstacle protection for ‘traditionally’ flown non-precision approaches as well as with the protection for approaches with vertical guidance (APV) using the criteria contained within ICAO PANS OPS. The AWOSG is convinced that using the MDA/H as a DA/H offers adequate obstacle protection. Another comparison between the CDFA technique and the ‘traditionally’ flown non-precision approaches indicates that the latter involve several safety traps, such as:
- Early descent with a prolonged flight close to obstacles;
- Multiple step-downs possibly inside the FAF;
- An approach which is, by definition, destabilised;
- Temptation to make a late and steep descent from MDA/H towards the threshold;
-Risk of descending early from the MDA/H;

While there are no records of accidents related to the use of the CDFA technique during approach operations, there are several accidents attributable to the risks listed above.
The matter of using the MDA/H as a DA/H is progressing in the ICAO OCP and OPSP. Until there exists a final result of the work in ICAO, it must be left to the discretion of each Authority to make decisions on the matter. Since the benefits of the CDFA technique are generally acknowledged, the decision is typically whether to require an add-on to the MDA/H to ensure that the height loss does not lead to flight below the related MDA/H during a go-around, based on formal or other reasons. It is not the intention of this NPA to imply that an add-on to MDA/H must be required, but rather an acknowledgement that it is an option. In order to facilitate the decision-making process, the evaluations referred to above can be made available in the form of Power Point slides and working papers. In addition, a short paper by Mr Theo van de Ven (KLM) outlining the safety arguments in favour of using MDA/H as a DA/H is attached at the end of this Explanatory Note (See Attachment A).
At the latest meeting of the ICAO OCP (WG of the whole in Singapore in November 2006, it was recognised that the use of DH in connection with the CDFA technique, could be acceptable from an obstacle clearance point of view and that future work should be referred to the ICAO OPSP, The CDFA uses a DA(H). The DA(H) figure is derived from the OCA(H) for the associated procedure plus any buffer decided by the operator or the authority. MDA(H) is the lowest altitude (height) for the level portion of an approach flown using the traditional dive-and-drive technique, not the CDFA technique. Use of MDA(H) would undermine the philosophy of the CDFA. The AWOSG has undertaken several studies which conclude that the use of MDA as DA is safe (attachment A to this document, WP 9 to OCP WGHL, March 2006 by Mr T v d Ven, NLR-report CR-2000-451 by Mr H.W. Kleingeld and in “A statistical look at the safety of CANPA procedures”, 11 June, 2002 by Capt J Meijer, RLD). If an operator or an authority thinks that mitigation is needed anyway, this can be done by means of a buffer and/or procedures and training. NPA OPS 41 does not prescribe how to decide, but leaves this to the NAAs. Use of the CDFA technique is considered as a significant safety improvement. (Ref to ALARP). It is also important to note that the NPA does not suggest anything that is not already in widespread use by European operators.

[BOAC]

When you fly NPA as CDFA, you may use MDA/H as the DA/H with no height add-on. - Savi, we have been flying 'CDFA' - as in 'continuous descent final approach' now for many years - probably 20 or more since the UK airlines at least dropped the d&d technique. I think it is important to differentiate what we have been doing for years - which DOES require an addition as per the AB note you posted - from the 'New' CDFA which does not, but must be approved by the operator and regulatory authorities. Those airlines using the traditional 'CDFA' we all know still need to apply an addition of some sort as per your

"Part 1 - minimum is MDA(H) - CDFA or non CDFA
The MDA(H) being a minimum descent altitude, no altitude loss below the MDA(H) is allowed during the approach and go-around; this implies to either:
− Level-off at the MDA(H) - step-down / dive-and-drive technique - until visual references are acquired:
− Initiate the go-around above the MDA(H) - constant descent-angle technique - if no visual references are acquired, in order not to “duck under” the MDA(H).

Part 2 - minimum is DA(H) - only CDFA
This is obviously not required when the applicable minima is a DA(H), which is a decision altitude; if no visual references are acquired when reaching the DA(H), a go-around must be initiated at DA(H)"

and your note from JAA itself says "The matter of using the MDA/H as a DA/H is progressing in the ICAO OCP and OPSP. Until there exists a final result of the work in ICAO, it must be left to the discretion of each Authority to make decisions on the matter." so I felt your initial words (as quoted at the top) could be misleading. As always, stick to what your company tells you to do.

[shazapis]

BOAC,

How do you determine (by looking at the plate) whether a procedure is a true DA(H) kind, approved by the authority, or just a revised chart format (jepessen says they will only indicate DA(H), even if the original procedure uses MDA(H), and they make no additions whatsoever).

I believe the safest option, until it all clears out, is to add 50ft to ALL NPAs indicating a DA(H) on the plate.

Spiros Chazapis
Athens, Greece

PS Thanks for all the replies guys, they are very appreciated

[BOAC]

Check the Jeppesen link (page 2) in post #11

[shazapis]

BOAC,

Hm, I don't think this is very conclusive. First of all, the link points to a "chart clinic" article that is quite old (1999-ish). A lot have changed since.
Then, I believe that it doesn't really apply outside FAA-landia. For instance (extract from this document):

"And the big “IF.” The MDA may be used as a
DA only if there has been a visual segment
obstacle assessment made for the straight-in
landing runway. The FAA has stated that
there has been an obstacle assessment when
the runway has a VASI or PAPI as a visual
guidance system indicator, an electronic
glideslope, or an RNAV approach published
with a decision altitude.
Since an obstacle assessment has been made,
the FAA has authorized the DA since it is
assumed that a momentary descent will be
made below the DA during the execution of
a missed approach.
When there is a VDP, it should be at the point
where the descent angle meets the MDA."

So, no addition to the MDA(H) if the runway has PAPI lights? Also, the point about "momentary descent etc" is clearly in violation of PANS-OPS.

I found a reference to the 50 ft, but not on a regulatory document - it's in an FSF ALAR briefing note (7.2, page 5) that states

"Approaching the MDA(H)
At an altitude corresponding to the MDA(H) plus 1/10 the rate of descent (typically MDA[H] plus 50 to 100 feet), anticipate a go-around decision to avoid descent below the MDA[H], as required by applicable regulations".

I still believe that the safest option on CDFA NPAs is to add 50 feet to all procedures, until there is a positive way to identify DA(H) procedures that originate from the authority and not the charting company...

Spiros Chazapis
Athens, Greece

[BOAC]

Shaza - the whole thing has been made unnecessarily complicated by the EU authorities. The safest thing for you is to "follow your company procedures" as they should have been approved by your regulatory authority. If those 'procedures' are not clear, ask for a ruling from your Training department. They should have issued you with guidance on how to apply the 'new' minima where they appear. If you cannot get an answer, adding 50 is safe, of course.

[LLLK]

Ok We've been here before. EUROCONTROL issued a Safety Reminder Message back in February:
EUROCONTROL - Safety Alerts Board (http://www.eurocontrol.int/safety/public/standard_page/safety_alert_board.html)

[BOAC]

Thanks LLLK - I could not afford the time to locate that. It is not really much help - what do you do if your company has not adopted (or published) the 'new' procedure? I think elsewhere we were given an implementation date of July 2011? A whole year of fun for some.
"n Aircraft operators are invited to: § Note the issue above specifically with a review of the need to consider the requirement for an add-on factor to account for height loss at missed approach initiation."


Just a little Euro-Woolly!! but again refer to your company, Shaza. If in doubt, add!

[LLLK]

The problem as I see it is that many European operators have been flying stabilised approaches for years and have been following the PANS-OPS guidance that has been there since Pontius: The DA/DH is based upon the OCA/H with an additional margin 'based upon operational consideration of
– category of operation
– ground/airborne equipment characteristics
– aircraft performance
– meteorological conditions
– aerodrome characteristics
– terrain profile/radio altimeter
– pressure error/pressure altimeter
- etc.

And they usually came up with a figure in the region of 50ft - although some decided that no add-on was necessary.

EU-Ops tried to capture all this in the CDFA and RVR sections without much success. EASA is in the process of rewriting EU Ops as IR Ops but it could be some time before that sees the light of day. In the meantime, States have committed themselves to publishing RNP APCHs to LNAV/VNAV minima for all instrument runway ends by 2016 (or thereabouts). If you fly to LNAV/VNAV minima the problem goes away.

I have heard that at least one major European State has taken a similar view to the FAA - if the visual segment has been appropriately assessed for obstacles (it has to be done for RNP APCH to LNAV/VNAV) then MDA=DA. But then if there is an LNAV/VNAV approach published, why fly CDFA on a conventional NPA?

[shazapis]

BOAC,

"if those 'procedures' are not clear, ask for a ruling from your Training department."

... that would be me I guess :ugh:

I am the Stand/Eval officer (something like a flight standards officer of an airline) of a military transport squadron in charge of SOP development. We had a sudden wake up call when CDFA procedures plates for LGSA landed on our doorstep, and I now have to figure out a way out of this mess. Needless to say, our previous SOP manual did not include any specific procedural guidance for CDFA NPAs (just a generic statement that it is the preferred way to do it), although we have been aplying stabilized approach criteria for quite some time now.
To make things more complex, our planes have been recently retrofitted with modern avionics, adding to the complexity of developing standard ops (the steam gauge suite was way simpler...).

Ofcourse we are also talking to other squadrons that share the same problems (military operators are used to getting very little guidance from manufacturers on these issues - thus the delay in implementing procedural changes...)

rgrds

Spiros Chazapis
Athens, Greece

[BOAC]

Aha! I sympathise! Not sure who produces your plates? In the absence of an edict from 'higher command', I think what I would have done in my days as a RAF Command IRE would simply be to issue an instruction that where the plate is annotated DA/H, use it as such, and where it says MDA/H add 50'. If you have that authority, I'm sure that would keep you safe until it is all resolved - and if anyone from command 'bleats' about it say "Well, where were you when I needed you?"

[johns7022]

Sounds like an argument for check airman, people who write SOPS manuals, and chief pilots hoping that the 500 hour FO doesn't bust down to low..

In the real world...50 ft is only there as a place to start leveling out when you don't see the glow, gives you time to push some throttles forward, clean things up....

I don't think anyone really cares if you go 25 below DHA/MDA on a real flight...this whole thread is about check rides and sim sessions....

[shazapis]

BOAC hi,

We have a MAIP (Military - AIP) that includes only Greek airports. For other airports we use DoD FLIPS, CENOR, UK military FLIPS (RAF No 1 AIDU - produced) and of course Jepessen. Our SOPs are based on Jepessen charts (to describe the standard approach briefing for instance).

Naturally, on issues like this one, the opinion of the operator (the squadron) is very important to HQ - they will almost always approve the squadron's point of view on procedural matters (as long as it is properly justified), so we want to make sure we get this right.

johns7022:

I see your point of view. Nevertheless, I believe that procedures have to be, amongst other things, in accordance with regulations. If a 50 ft requirement is deemed appropriate and is included in a regulatory document, this requirement has to be reflected in the SOPs. What can or may happen during line flights is a different (also very interesting) issue.

Anyway, this has been a very interesting discussion indeed - once more, thank you for all the replies, they are very appreciated.

Regards,

Spiros Chazapis
Athens, Greece