Required landing distance available. Does inflight requirement exist?

[Vaneev]

My question to pilots who fly in accordance with JAR–OPS.
Below I quote JAR–OPS requirements (in short)
Please, tell me does this requirements only for dispatch, or they are valid, when pilot in flight make a decision to land or not to land?
If special inflight requirements exist, please quote.

Thank you in advance.

JAR–OPS 1.515 Landing – Dry Runways
(a) An operator shall ensure that the landing mass of the aeroplane... allows a full stop landing from 50 ft above the threshold:
(1) For turbo-jet powered aeroplanes, within 60% of the landing distance available;

JAR–OPS 1.520 Landing – Wet and contaminated runways
(a) An operator shall ensure that... runway... may be wet, the landing distance available is at least 115% of the required landing distance, determined in accordance with JAR–OPS 1.515.
(b) An operator shall ensure that... runway... may be contaminated, the landing distance available must be at least the landing distance determined in accordance with subparagraph (a) above, or at least 115% of the landing distance determined in accordance with approved contaminated landing distance data or equivalent, accepted by the Authority, whichever is greater.

[Denti]

Hmm, as the EU does not fly according to JAR-OPS anymore there are only very few countries that might still use them. Dunno if EU-OPS differs there much to be honest, and come april we gonna have the all new EASA-OPS.

[Vaneev]

I am sorry. I repeat my question regarding to EASA-OPS (content has not changed )

CAT.POL.A.230 Landing — dry runways

(a) The landing mass of the aeroplane ... shall allow a full stop landing from 50 ft above the threshold:
(1) for turbo-jet powered aeroplanes, within 60 % of the landing distance available (LDA);

CAT.POL.A.235 Landing — wet and contaminated runways

(a) When ... the runway ... may be wet, the LDA shall be at least 115 % of the required landing distance, determined in accordance with CAT.POL.A.230.

(b) When ... the runway ... may be contaminated, the LDA shall be at least the landing distance determined in accordance with (a), or at least 115 % of the landing distance determined in accordance with approved contaminated landing distance data or equivalent, whichever is greater.

[safetypee]

In this regard, EU-OPS 1 is sufficiently similar to JAR-OPS 1 for an interpretation to be the same; note ‘interpretation’.

There is little regulatory guidance (EASA) on how the dispatch / pre-landing (in-flight) assessment of landing distance should be equated. However, recent UK CAA advice clearly outlines their interpretation:-

“Before commencing an approach, the commander is required to ensure that a safe approach and landing can be made given the updated meteorological and runway surface condition (see EU-OPS 1.400).
The operator is required to demonstrate that it can ensure safe operations, and by applying the same additional safety margin to the in-flight performance assessment as to the dispatch assessment demonstrates an equivalent level of safety.”

The quote is taken from Appendix 1 of Safety Notice SN–2011/016, Operations on Contaminated Runways.
Although the document is titled ‘contaminated’ it provides a wide range of information of landing performance issues and safety, with obvious focus on operations on contaminated runway, which are allowed in EU-OPS (and CS-25).

Thus the in-flight decision to land should be based on the same landing distance factors as for dispatch.

[Geardownandlocked]

These requirements are incorporated in the QRH LDR (Landing Distance Required) table. So no need to do the calculations yourself. So we apply these requirements during flight. Only in case of emergency it is allowed to use the 'actual landing distance' tables.

So to answer your question, there is no difference between what dispatch might calculate, and what we use during flight.

I hope this answers your question!

[safetypee]

Geardownandlocked, I would add a caution to your general view.
Perhaps not all aircraft types or operators have factored landing distance available for all airports / runway conditions / landing configuration / mass.
e.g. the Boeing supplied QRH for the B737 only has actual distances. Thus some calculation is required before landing.

Also, there could easily be a difference between what dispatch has calculated and what should be considered before landing.
e.g. for dispatch EU-OPS 1 requires use of the most likely landing runway, and use of current / forecast conditions. Thus before landing the crew must assess the actual conditions for the planned landing; - the wind for the chosen runway, the runway state / braking action, crosswind (effect on braking).
This should not be a quick recheck of landing mass to give a go/no go solution, but an evaluation of the margin between the required and available distances to judge what additional factor is available. This provides a guide to the level of braking required, expected turn-off point, etc; and also guarding against some of the unknowns in landing – touchdown speed, position, actual runway friction, tyre conditions.

[de facto]

FAA QRH distances i believe are unfactored,JAA are.
Same as JAA include line up distance for torr,faa uses from brake release point.
Different regulatory bodies,different calculations...
ALWAYS calculate your landing distance,it avoids choosing inapproriate a/b settings,position awareness in low vis,and be confortable if last minute change to a shorter runway or if weather/runway conditions changed since dispatched.
Learn your extra distance based on your every day skills..

[FE Hoppy]

OPS 1.475
General
(a)An operator shall ensure that the mass of the aeroplane:
(1) at the start of the take-off; or, in the event of in-flight replanning
(2) at the point from which the revised operational flight plan applies, is not greater than the mass at which the requirements of the appropriate subpart can be complied with for the flight to be undertaken, allowing for expected reductions in mass as the flight proceeds, and for such fuel jettisoning as is provided for in the particular requirement.

An operator shall ensure that the approved performance data contained in the aeroplane flight manual is used to determine compliance with the requirements of the appropriate subpart, supplemented as necessary with other data acceptable to the Authority as prescribed in the relevant subpart. When applying the factors prescribed in the appro- priate subpart, account may be taken of any operational factors already incorporated in the aeroplane flight manual performance data to avoid double application of factors.
When showing compliance with the requirements of the appropriate subpart, due account shall be taken of aeroplane configuration, environmental conditions and the operation of systems which have an adverse effect on performance.
For performance purposes, a damp runway, other than a grass runway, may be considered to be dry.
An operator shall take account of charting accuracy when assessing compliance with the take-off requirements of the applicable subpart.


Landing — dry runways
(a) An operator shall ensure that the landing mass of the aeroplane determined in accordance with OPS 1.475(a) for the estimated time of landing at the destination aerodrome and at any alternate aerodrome allows a full stop landing from 50 ft above the threshold:
(1) for turbo-jet powered aeroplanes, within 60 % of the landing distance available; or
(2) for turbo-propeller powered aeroplanes, within 70 % of the landing distance available;

[Dream Land]

From a 2007 Boeing seminar:

Landing Distance and Runway Length Required
The landing distance is defined by FAR/JAR 25.125 to be the horizontal distance to come to a complete stop from a point 50 ft above the landing surface, assuming
• Airspeed at the runway threshold is VREF.
• A level, smooth, dry, and hard surfaced runway. • Airport altitude and standard day temperature. • 50% of the headwind or 150% of the tailwind. • Maximum manual braking.
• No reverse thrust.

[safetypee]

Dream Land, you appear to be intermixing certification and operational requirements.

The ‘Landing distance’ for certification is defined in FAR/CS 25; this is usually referred to as the un-factored landing distance. This is the ‘dry’ landing distance which the manufacturer establishes as the baseline for landing performance.

The ‘Required landing distance’ comes from the operational regulations (FAR 121 / EU-OPS) which require the operator to use factored distances depending on aircraft type (jet/prop) and the runway surface condition (dry/wet). In the EU there is a separate category for contaminated operations with different baseline standards and operational assumptions.

The central theme of the thread is if the factored distances required for dispatch also apply to the actual landing requirements. The wording of the operational regulations is not particularly clear, but in the EU it appears to be generally accepted that a factored distance based on actual landing conditions should be used.
A basis of this is the intent to achieve a level of safety for landing which is equivalent to that required for dispatch.

In the US, the certification and dispatch requirements are essentially the same, but the safety aspects and landing distance required in a pre-landing assessment are less clear. The advice in the advisory guidance SAFO 06012 (August 2006), is potentially confusing, but essentially requires:- (A) that operators conduct a pre-landing assessment, and (B) the landing distance required is at least 15% over the ‘actual landing distance’.
The ‘Actual landing distance’ is not necessarily the manufacturer’s un-factored distance or the dispatch distance, but some in-between value representing what best distance might be achievable by line crews, e.g. B 737 QRH 'actual distance'. It is not a fully factored distance, and thus even with 15 % margin this distance is probably less than the dispatch distance, and thus has a smaller safety margin.

A related Boeing presentation is here:- Slippery Runways

[FE Hoppy]

The central theme of the thread is if the factored distances required for dispatch also apply to the actual landing requirements. The wording of the operational regulations is not particularly clear, but in the EU it appears to be generally accepted that a factored distance based on actual landing conditions should be used.

I think it's pretty clear isn't it. If you re-plan in flight you need it. If you don't re-plan you already have it. The only time it isn't required is when abnormal or emergency factors are used.

[safetypee]

FE Hoppy,
Unfortunately, discussions and experience has identified that several operators and many pilots do not interpret “or, in the event of in-flight replanning” as being applicable to planning an approach, as in requiring a reassessment of the conditions for landing – ‘it only applies to diversion’.
The above could also infer that many of these operators/crews did not consider reassessment being necessary either, - a quick check of the landing mass would be OK !

[mutt]

I would read "Re-planning" to also cover re-release or redispatch, so you cannot use this procedure to get around the landing runway requirements, however if you have an inflight emergency, you can dump the aircraft on a non-factored runway length.

It was interesting to note that following the Swissair MD11, aircraft manufacturers started providing non-factored landing distances in their QRH's (FAA). that would lead me to believe that they dont want to take the legal responsibility of giving you a landing distance requirement greater than certification requirements.

[9.G]

New FAA TALPA concept addresses so-called operational landing distances. It's more realistic concept based on average piloting skills taking into account actual aircraft, weather and airdrome conditions. It's actual landing distance with a regulatory margins applied. It'll be manifested mid 2012.

[Geardownandlocked]

@safetypee

I was assuming that the table named QRH 'LDR' (note the 'R' - Required) implies that it is already factored, and this would be clear to anybody. Especially since there is also a table for the 'actual' landing distances. I see no reason to be cautious here. But I'm only familiar with my own company procedures.
You mention that the Boeing supplied QRH only mentions 'actual' landing distances. I suppose this would be because Boeing doesn't want to be between the regulatory organ and the airlines flying their planes. They just have the test results, which are used to calculate the 'actual' landing distances. Am I wrong to assume that all airlines would supply their pilots with a 'required' landing distance table? Because it would be a pain to calculate this every time before landing.

And ofcourse the circumstances under which dispatch, and the pilots before landing, would be different, resulting in a different calculated RLD, but I thought we were speaking about fundamental differences between the way dispatch calculates, and the way pilots calculate. To my best knowledge, there is no difference.

[safetypee]

Geardownandlocked, my caution was aimed at the industry wide issues, not your specific documents.

I don’t know why manufacturers don’t supply factored distances; perhaps due to the apparent differences in use between FAA and EU requirements.
To add to any confusion, the Boeing ‘actual’ distances which I referred to (B737 QRH) are not the same values as the certificated actual landing distances (AFM), this is because Boeing include reverse thrust and recommend the use of a different (but still short) airborne distance.

Re differences in dispatch and airborne calculations:
In the EU there should not be any difference in the method, and with the same data, nor in the result; but note that dispatch is usually on forecast conditions, whereas the crew must use actual conditions. Also some dispatch options can use still air.
In the US it is unlikely that the methods/distances will be the same, the in-flight calculated distances being shorter (ref SAFO 06012), but I am not sufficiently experienced with their system to be sure of the increased risk.

[safetypee]

9.G, my understanding of Operational Landing Distances (OLD) is that only a 15% margin (FAA) is applied; this is not equivalent to the factored landing distances discussed previously, instead more like the shorter Boeing ‘actual’ distances.
Although TALPA has been led by the FAA and US operators, EASA is taking an interest in the reporting matrix.

TALPA background - FAA conference 2006 - Runway Condition Determination, Reporting, and Report Dissemination Workshop

A more recent update - EASA conference 2010 - Workshop on Runway Friction and Aircraft Braking

Boeing and Airbus views are presented; Airbus provides good comparisons with EU OPS and FARs and a realistic view of operational landing distances (OLD).
Although Airbus support OLD, the concluding slides (23/25) notes many problems, not least introducing (more) risk.
Also, if the 15% margin were retained by the FAA and the full factored distance by EASA, then there would not be a level playing field for the manufacturers amongst EU vs FAA operators. FAR operations could claim a shorter distance from an in-flight reassessment, but EU operators could not.
This also raises the issue that although OLD with 15% margin might be shown to be equivalent to current EU requirements for landing distance, it may not be equivalent in safety as OLD uses reverse thrust (generally not considered in certification).
With the current poor overrun safety statistics it might be foolhardy to increase the risks during landing operations.

[9.G]

as everything else the factored Required LD is only applicable at dispatch unless overruled by operators OM. In flight only actual LD matters which, as pointed out, conform with the current legislation doesn't reflect the reality. Operational landing distance concept is much more than just a mere 15% factor. It's a fundamentally new approach to actual landing performance assessment not only on the line but during certification as well, in particular on contaminated RWY. Moreover it finally binds the operator to implement realistic assessments online on daily basis. As for reversers, well there're there to be used and if they do shorten the landing distance then I don't see any reason why it shouldn't be accounted for.

[safetypee]

9.G, I believe that your first two sentences relate mainly to FAR operations.

The exact components of Operational Landing Distances (OLD) are not entirely clear, nor are the applications. There are indications of differences between Boeing and Airbus, FAA and EASA.

AFAIK there is no intent to change the basis of the certificated landing performance (manufacturer’s actual distances). Thus OLD is only an operational issue, but to add to the confusion Airbus also refers to an 'operationally’ factored OLD (FOLD !) which appears to use a 15% margin.
Furthermore Airbus hints of an undisclosed ‘factored’ equivalent of OLD which could be used for dispatch.

‘As for reverse’: reverse thrust is not used to determine certificated landing distances unless the manufacturer can demonstrate a consistent high level of reliability – Midway and other accidents indicate why. The EU has a caveat for contaminated operations where reverse can be considered; the additional risk is mitigated by infrequent exposure to those operations. There are similar alleviations in AC121-195 for FAR wet runway operations with restrictions, but applications are few if any.

Whilst most operations use reverse, there is a tendency to rely on it, particularly in deteriorating conditions. Also, contaminated operations are increasingly being considered as ‘the norm’ without any other risk mitigation.

[Sir George Cayley]

Now the CAA are doing something

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