Max Approach slope A320/B737

[Labomba]

Gents, Ladies,
Could any one of you find the following piece of info:
I'm looking for the max glide slope angle a B737 or A320, not modified, can fly.

I'm aware of the max slope for auto land. Not what I'm asking. Max slope for auto approach, manual landing.
I'm aware of the specially certified A318 for London City, not part of the question.

I don't find anywhere a limitation for a std 320 or 737, but it should exist...

Why this question? Because we are asking some companies to design new approaches in mountainous areas, and would like to know what is acceptable.
Thanks a lot for your input, if you know the answer..

[TopBunk]

Surely the answer is for you to approach Boeing and Airbus for the answer, rather than to rely on an anonymous internet forum where the answers, whilst maybe trying to help, can't be relied on at all?

I am having trouble believing you are really a professional involved in what you suggest ....

[PEI_3721]

Bomba, I doubt that a value is published as a limitation.
An aircraft’s capability is a function of the drag margin in the approach configuration, with a power setting sufficient for anti-icing and GA spool-up. An operational assessment normally includes lateral and vertical manoeuvre capability to join and maintain an approach path.

There is normally a division between a straight-in approach and landing - the ability to stabilise and flare on a runway vs an airfield approach.
The requirements for an airfield approach may be not so well defined as for steep approach, and might depend on national or local clearances (also see RNAV GPS approvals). An old example involved the BAe146 operating into Aspen without a precision glidepath, i.e. NPA; this was based on a ~6 deg descent into a valley to provide sufficient distance / time to adjust for lower (3deg?) or a circling approach.
This type of approach is not now recommended as an industry standard, thus I suspect that many authorities will require a precision approach path. However, with something like GPS it might be possible to argue a transition to a lower approach path or circling procedure, but with higher minima.

A steeper approach capability before a ‘circling’ approach might be achieved by flying a higher speed than for a straight-in landing (more drag), but this could require more time / manoeuvring area.
In the types of aircraft being considered I would not expect any approach path greater than 6 deg to be approved – it’s not sensible / economic (approval cost / training / currency).
Approvals are normally easier if based on ‘hard data’, e.g. A318 at LCY and extrapolate to a larger aircraft by demonstration, e.g. 4.5 – 5.5 deg.

If terrain remains a problem consider a specialist curved/segmented procedures based on RNAV waypoints; there are some good examples –
Air New Zealand. Qantas (737) Queenstown
Air Alaska (737) Gastineau
Required navigation performance - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Required_navigation_performance)
Druk Air into Paro, Bhutan (A318)
The Himalayan airport so dangerous only eight pilots are qualified to land there | Daily Mail Online (http://www.dailymail.co.uk/news/article-2079836/The-Himalayan-airport-dangerous-pilots-qualified-land-there.html)

[BOAC]

Like PEI I do not think it is 'published' but is down to airline preference. We used to operate 4 deg slopes at LFML and LFLB and I think I might even have done 4.2 somewhere.

[vilas]

This has been answered before by cloud runner




cloudrunner
11th Dec 2012, 20:55
From:
Official Journal of the European Union, REGULATIONS.
COMMISSION REGULATION (EU) No 965/2012,of 5 October 2012.
SUBPART C
AIRCRAFT PERFORMANCE AND OPERATING LIMITATIONS
SECTION 1
Aeroplanes
C H A P T E R 2:

CAT.POL.A.245 Approval of steep approach operations

(a) Steep approach operations using glideslope angles of 4,5° or more and with screen heights of less than 60 ft, but not less than 35 ft, require prior approval by the competent authority.

(b) To obtain the approval, the operator shall provide evidence that the following conditions are met:

(1) the AFM states the maximum approved glideslope angle, any other limitations, normal, abnormal or emergency procedures for the steep approach as well as amendments to the field length data when using steep approach criteria;

(2) for each aerodrome at which steep approach operations are to be conducted:

(i) a suitable glide path reference system comprising at least a visual glide path indicating system shall be available;
(ii) weather minima shall be specified; and
(iii) the following items shall be taken into consideration:
(A) the obstacle situation;
(B) the type of glide path reference and runway guidance;
(C) the minimum visual reference to be required at decision height (DH) and MDA;
(D) available airborne equipment;
(E) pilot qualification and special aerodrome familiarisation;
(F) AFM limitations and procedures; and
(G) missed approach criteria.

[BOAC]

(1) the AFM states the maximum approved glideslope angle, any other limitations, normal, abnormal or emergency procedures for the steep approach as well as amendments to the field length data when using steep approach criteria; - not much help when that is what Labomba wanted:ugh:

[Gysbreght]

BOAC,

read paragraph (a) again. The AFM is an airworthiness document. To get the approval into the AFM involves the Type Certificate Holder (usually the manufacturer) and the airworthiness authority that issued the Type Certificate.

[Amadis of Gaul]

I am having trouble believing you are really a professional involved in what you suggest ....


Come now, Topbunk, don't professionals routinely get answers from anonymous fora? Everything written on the internet is true, as we all know.

[PEI_3721]

Gysbreght, the issue of glideslope vs descent is a grey area.
Based on my (dated) experience, the EU OPS (previously JAR OPS) requirements stem from the certification requirements for steep approach; the results of which, as you state, are published in the AFM. However, in the absence of a specific certification regulation (previously a STOL / FWG working paper), the certification basis appears to be the operational requirements – a circular reference.
Here, glideslope has been interpreted as requiring precision guidance for a straight-in landing – electronic or visual (PAPI).

A descent without precision guidance has been referred to as a vertical path, see CS25 AMC No. 1 to CS 25.1329 Flight Guidance System, Appx 1, 4.2.3.3 Assessment – Approach without Vertical Path Reference :rolleyes:
Note that the FGS requirement – use of AP, requires special approval above 4.5 deg.
I would not be surprised to see other references creep out of the woodwork of certification.

Therefore there appears that there is no specific limitation on an aircraft’s descent path i.e. = max rate of descent; cf descents prior to capturing an ILS GS.
Thus I see the issue in Bomba’s question as how far the descent analogy can be extrapolated for an approach to an airfield, but not necessarily a runway for a straight-in landing. My previous post attempted to distinguish between these.
Again there can be grey areas; Sion (LSGS) 6 deg ‘precision’ descent to 3.5 GS, and Lugano (LSGA) 6.65 deg descent for a visual (PAPI) straight-in landing; but I fear that my experiences are out of date.

P. S. Canadian background https://www.tc.gc.ca/eng/civilaviation/certification/guidance-525-525-011-314.htm
And from EASA NPA 2011-09, but where this has ended up, who knows???
"Steep approach and landing Flight test and structure item
The scope of CS-25 does not cover steep approach and landing capability and consequently additional airworthiness requirements are required with provisions to enable an aeroplane to use an approach path angle greater than or equal to 4.5° (a gradient of 7.9 %). Certification Review Items have raised an appendix containing these additional requirements which have evolved over the years and the most recent standard is proposed here. The requirements of this appendix cover only CS-25 Subparts B and G and they apply in lieu of CS 25.121(d). … It is therefore proposed to create a new Appendix Q in Book 1 and an AMC to Appendix Q in Book 2."

P P S ‘Q’ found it. Page 281 – note definitions ‘an approach to land’; nothing for the airfield.
http://easa.europa.eu/system/files/dfu/00%20Annex%20to%20ED%20Decision%202014-026-R.pdf

[CaptainSandL]

I can confirm that 737CL & NG AFMs only have a max glideslope for automatic landing as follows:
"The maximum and minimum glideslope angles are 3.25 degrees and 2.5
degrees respectively."
But nothing for non-autolands.

[Labomba]

gents, thanks a lot for your input. As a few of you found out, has to be (at least following the EU Ops) below 4.5° , and here is what Mr Airbus says:

“A320 family aircraft are certified for approach with a flight path angle up to 4.5° excluded.



Approaches with a glide slope angle from 4.5° and up to 5.5° are categorized as Steep Approaches in the EU OPS regulation.

According to Appendix 1 of EU OPS 1.515 (a)(3) “Steep Approach Procedures”, it is not permitted to perform an approach with a glide slope angle equal to or greater than 4.5° without an Authority approval.



The Steep Approach Landing is not a standard procedure on Airbus aircraft and is consequently not documented in the standard Aircraft Flight Manual (AFM). Steep Approach Landings are only certified on A318, and only after modifications embodiment on the aircraft.”

Happy to read we may design a 4.2° along our terrain...

[STBYRUD]

I can only speak from personal experience - the steepest approach I've flown in the 738 was a 4.5° final descent, but thats fully configured at flaps 40 from the top down. Anything steeper or the slightest tailwind and you won't make it.