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Runway End Safety Areas (RESA)

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Runway End Safety Areas (RESA)

Old 27th May 2007, 21:02
  #21 (permalink)  
Sir George Cayley
Posts: n/a
Dear Overun Eng,

With all due deference to your knowledge and experience I must disagree on one point with regrds to ICAO.

As I've trod its corridors on more than one occassion trying to change the world, I have to say that my confidence in any Standard it has recently ratified is weak.

Lowest Common Denomiator is the phrase that always goes thru' my mind.

240m may be too much, Rolls Royce, Gold Plated etc but 90m does not stand up to examination against the sort of design a/c one has to deal with today.

Also the reduction of RESA for minor infringements at the lateral extremes gives airport operators a get out they should not enjoy.

I don't have all the data in front of me but I'm sure you would agree that if just one passer-by had been killed 91m from the end of a runway it would be unacceptable.

Surely, the right process should involve a calculation based on all the contributory factors that surround each runway, inc its surface, the LDA, wx, and design a/c plus most frequent a/c, to arrive at a figure that can be demonstrated as being acceptable on a LARP basis?

If that was 90m, 240m or 500m people living under the shadow of a runway would receive the protection appropriate to the airport it served.

I offer this opinion without prejudice and in the spirit of improving safety thru dialogue. The fact I'm descending in to a deep bunker is purely coincidental.

Sir George Cayley

In saying LDA I shouldd have included ASDA but assumed everyone would know this.

Last edited by Sir George Cayley; 28th May 2007 at 16:03. Reason: Just had another thought
Old 31st May 2007, 12:52
  #22 (permalink)  
Prof. Airport Engineer
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Sir George Cayley
My apologies in the delay in replying – partly because student demands have been high (I like to say the students were revolting; not PC) – but mainly because I did not want to treat your important issue too lightly.
the right process should involve a calculation based on all the contributory factors that surround each runway, inc its surface, the LDA, wx, and design a/c plus most frequent a/c, to arrive at a figure that can be demonstrated as being acceptable on a LARP basis
(LARP or ALARP = as low as reasonably practicable)
UK CAP168, in Chapter 3, section 5, expands on this process, and calls for airports to review and determine on an annual basis the RESA distance required for individual circumstance taking into account, in their risk assessments, a range of such factors.

There are at least three diverse approaches to this aspect of safety, and they each have their advantages and weaknesses.

Discussing these for the case of RESAs for code 3 / 4 aircraft:
1. The ICAO approach of simple prescription (90m mandatory, 240m recommended).
I find great elegance and sophistication in the simplicity of ICAO rules like this. In the field, I am struck by how many of these simple rules (another example of such a rule is the 'average texture depth of not less than 1mm') give an excellent result even when tested by the real world variability. The result is often not improved by application of more complex methods. The rule simplicity means they can be applied by all of ICAO's many and diverse member states. If one calculates risk in societal terms, the net improvement in global safety by applying simple rules to all the Member States is greater than by applying highly sophisticated rules to a handful of advanced States. (And shopping mall managers and accountants can't fiddle them which must be good).

2. The UK CAP approach opens the door to the calculated risk assessment, ALARP school of thought.
This approach is similar to some ATC risk analyses, and derives from systematic risk assessment from nuclear, oil/gas, and chemical industries (to name but a few). In Australia, we have a relevant standard (AS 4360:1999 Risk Management), and the aviation regulator has various procedures on the Preparation of Safety Cases.

These approaches have policy/bureaucracy attractiveness because they "cover your arse". They have a real engineering attractiveness because one can then design the safety of a system in an engineering sense. They appeal to accountants because they form a major input into cost/benefit ratios. I've used this approach for some projects and found them useful in complex and very complex cases (I did an AHP Expert Choice analysis for a runway upgrade the other day – rather surprised with the result).

Despite the good bits of this approach, the cynic in me worries that they are too open to fiddling by shopping mall managers and accountants (or their paid-for consultants).

And I worry that they lack teeth. Let me ask the question - does the wording of the new CAP168 mean anything? After all, CAP168 reads wonderfully. Unfortunately for me in Australia, after listening to many years of politically correct, wonderfully reading, best world's practice, but incompetent bureaucrats have left me a bit cold to "wonderful reading". So I look for what really happens before I do the "wonderful reading". Uncomfortably for some, I know where to look so as to be able to look at what really happens. In the UK for example, I'd look at Bristol Airport (BRS?). Anyone know the RESA lengths at Bristol? I don't know them, but if they are 90m or less, then let me strongly condemn CAP168 and its "wonderful reading". If they are 150-240m, then let me say that this 'calculated risk assessment, ALARP' school of thought really works. I do look forward to finding out the RESA length.

3. The probability approach.
This approach is typified by the excellent analysis by Kirkland, Caves et al in their paper An improved methodology for assessing risk in aircraft operations at airports, applied to runway overruns. I think there is great value here, although it is very sophisticated and very demanding of analysis. Perhaps too much for application to every airport at this stage, but in the next 10 or so years, perhaps we can do better.

There is a trio of papers which are going to be published the next 12-18 months and which will hopefully enable the probability approach to safety to be better applied to airports. The (only) one which I am not a co-author is titled 'Measures of Societal Risk and their potential use in Civil Aviation". This, I hope, gives the mathematics that will allow airports to make judgements about acceptable risk when using technology like the Kirkland approach.
Today, for me, I reckon that the lowest risk to global society is captured by the ICAO (simple) approach. But your approach is the best way forward – improving safety thru dialogue. I'm wide open to dialogue.
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Old 31st May 2007, 21:10
  #23 (permalink)  
Sir George Cayley
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Thanks Overun Ol' Chap,

Lots of food for thought there.

I have a contact at BRS, "Brizzol" to the locals, I'll ask him what the promulgate?

Thanks for the explanation.

Sir George Cayley
Old 1st Jun 2007, 15:52
  #24 (permalink)  
Join Date: Apr 2006
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Sir George, Overun,

Don't just look at the lengths, look at what they are made of. And don't stop at BRS..head for the setting sun.

And please look at the stopways as well.

And I agree totally with the general proposition that CAP 168 reads well, but has been written to mean very little, in terms of clear, unequivocal guidance about what is OK and what is not. The notion that CAA seems to espouse, and blame EASA for wrongly, is that the operator must now work it out for himself (eg risk assessment etc) within very general guiidelines, and take responsibility for what he decides.

And there we get back to the retail experts and bean-counters, who don't understand what it is they are taking responsibility for. And don't much care either; corporate responsibility, in the sense of Directors being charged as criminals when people are killed because they failed in their duty of care, and jailed if found guilty, does not really exist in UK*. (See large-scale fatal rail accidents, that will go on happening until a Director, preferably Managing, is jailed for at least 3 years per life lost, when they will stop, just like that.)

(* Unless the company is very small, and the Directors are not rich and well-known. In those cases, the law is merciless, and people are jailed. Think Lyme Bay canoeing drownings, for which the absent MD was rightly jailed.

But Reginald Corbett declared that the suggestion that he should be charged with manslaughter, after 120 or so people died because of appalling management of Railtrack of which he was Chairman, was obscene. (I think that's the word he used.) The law agreed, and as a result there have been two or more similar fatal crashes since then, all due entirely to bad management by people who "take full responsibility", and carry on as before. The same is going to happen in aviation, in UK at least, unless this is changed.

Last edited by old,not bold; 1st Jun 2007 at 16:13.
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Old 4th Jun 2007, 09:57
  #25 (permalink)  
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I've done a little research on UK airports, re the use of stopways, probably a bit late. It's not systematic, just a quick look at most of the Type A charts.

The good news is that most, including Bristol, declare TORA and ASDA as the same, so there is not a problem at those airports at least so far as stopways are concerned.

The poor one I referred to earlier still exists; but I feel that I should correct any impression that stopways that do not meet the requirements fully are a common problem.

But this does not alter my last post, above. There are variations from the required minimum standards, in all areas, at many airports and I do not believe there is sufficient pressure on the operators to put them right.
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Old 13th Jun 2007, 14:47
  #26 (permalink)  
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A runway end safety area shall be provided at each end of a runway strip where:
— the code number is 3 or 4; [this is the aircraft code – typical 3 is a B747, 4 is a B747]
— the code number is 1 or 2 and the runway is an instrument one.
The Australians (and possibly others) are less stringent and link upgrades partly to international flights.

B747 is code E 4 aircraft! Dont go mixing RPA vol 1&2 with annex14 to MOS139 they are not 100% the same.MOS139 applies to Australia only! and before I forget no one has mentioned CLY!!! not just RESA.The clearway is makes up TODA which is the length of the RWY+CLY allowing an ACFT to climb to a height of 35ft

Last edited by tomcat264; 13th Jun 2007 at 15:05.
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Old 18th Jun 2007, 12:18
  #27 (permalink)  

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Pardon me, but is this still correct?

Annex 14, Volume 1, number 4 dated 1 November 2001 states :-

3.4.7 Recommendation - A runway end safety area should provide a cleared and graded area for aeroplanes which the runway is intended to serve in the event of an aeroplane undershooting or overrunning the runway.

Note - The surface of the ground in the RESA does not need to be prepared to the same quality as the runway strip. See, however, 3.4.11.

3.4.11 Recommendation - A RESA should be so prepared or constructed as to reduce the risk of damage to an aeroplane undershooting or overrunning the runway, enhance aeroplane deceleration and facilitate the movement of rescue and fire fighting vehicles as required in 9.2.26 to 9.2.28 ( relating to emergency access roads ).

Note - Guidance on strength of a RESA is given in the Aerodrome Design Manual, Part 1.
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Old 18th Jun 2007, 12:45
  #28 (permalink)  
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Unfortunately no. The 4th edition came out without fanfare, and superseded your document. See hvogt's post near the top of the thread, which is from the 4th edition.

I must admit, in public, that I was wrong when I laughed at the ISO9000 quality systems that had a long winded section where the methods to ensure the recency/currency of design standards had to be stated.

I've been almost caught out by the 2006 FAA update in its heliport standards, the Boeing update of some of their airport planning documents and have only just seen the 2007 version of COMFAA.

At least FAA are open and accessible (big congrats to them). Boeing is better again (double congrats). ICAO operate in stealth mode, and are much harder to keep track of, Airbus operate in secrecy and Embraer aren't allowed to say if they operate (giant raspberry all round - or should that be framboise géante).
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Old 30th Oct 2007, 23:53
  #29 (permalink)  
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Dear All,

As a final year undergraduate student writing a dissertation on the proposed runway extension at Ronaldsway Airport (IOM), I have read your posts with great interest.

Does anyone know whether the 240m ICAO standards are set to be made mandatory by the CAA, or will they just represent best practice for the forseeable future?

Your thoughts would be much appreciated.

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Old 1st Nov 2007, 20:15
  #30 (permalink)  
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Extremely enlightening thread...

I too have a question for Overrun---you stated:

"Umm those who have looked at EMAS systems have come away shaking their heads in unhappiness. Lovely to see, lousy to own"---- I'm Really Really curious as to why?

sorry i don't know how to use the quote feature

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Old 2nd Nov 2007, 01:46
  #31 (permalink)  
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Maintenance + cost.

The same features which make them frangible mean they are abraded and weakened by the elements and jet blast. Plus it is a certainty that someone drives in them with a fire truck or similar and breaks them.

Then, "when they is broke" they are not easy to repair as one might say. The FAA AC No: 150/5220-22A summarises it nicely:

Repair. The EMAS must be designed for repair to a usable condition within 45 days of an overrun by the design aircraft at the design entrance speed. Note that this is a design requirement only. An EMAS bed damaged due to an incident (overrun/undershoot, etc.) must be repaired in a timely manner. The undamaged areas of the EMAS bed must be protected from further damage until the bed is repaired.

Not too many airports tolerate more than 6 or 7 hours out of service for the runway !!!!! At JFK after the overrun, it is reported that the damaged EMAS material was removed with front-end loaders and discarded. The aircraft was pulled out, and then new precast blocks were installed and finish coats applied. No comment as to how many weeks it took.

Finally, a quote from Juneau, Alaska. They have their own problems with climate, but the essence can be distilled out:


WHEREAS, the technical information about Engineered Material Arresting System (EMAS) supplied by the FAA does not establish that the technology works in all circumstances, and WHEREAS, technical information supplied by the manufacturer of EMAS establishes that the material is still being analyzed by testing contractors, and there is no track record of the technology's behavior in anything approaching a temperate rain forest similar to Juneau's climate, and

WHEREAS, after damage to EMAS due to an aircraft overrun, the runway safety area is compromised until repair can be accomplished, probably not a possibility in winter, and

WHEREAS, repair costs will be borne by the airport simultaneously with the costs of litigation to establish the responsible party, and

WHEREAS, frequent inspections of over five miles (one end) or over 10 miles (two ends) of caulked seams are required to maintain watertight integrity of the installed system, and

WHEREAS, snow and ice removal with special equipment would be required, and

WHEREAS, the cost of installing, maintaining and replacing EMAS is significantly more than the cost for a traditional extended runway safety area, substantially increasing capital and operational costs at the Juneau
International Airport, and

WHEREAS, these increased operational costs will ultimately have to be paid by the traveling public and the air carriers serving the public at the Juneau International Airport,

NOW, THEREFORE, the Airport Board of the Juneau International Airport, Juneau, Alaska, declares EMAS in its present form and at its present cost to be an unacceptable and unworkable alternative to runway safety requirements at the Juneau International Airport. The Airport Board declares that EMAS is neither a prudent nor feasible option for meeting the FAA's standard for runway safety areas at the Juneau International Airport.

The Airport Board of Juneau Alaska further declares that the installation of EMAS at the Juneau International Airport will unacceptably circumscribe the operating and maintenance budget unrelentingly for the foreseeable
years of the existence of EMAS and that consequently the Airport Board cannot commit any of its budget to either the installation or the maintenance of EMAS.

Passed this 8th day of June, 2005, in Juneau, Alaska.
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Old 5th Nov 2007, 11:53
  #32 (permalink)  
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For those of you who were curious as to what prompted the Juneau declaration cited by OverRun (as I was) - its here:

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Old 6th Nov 2007, 18:00
  #33 (permalink)  
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Thankyou very much Overrun,

Unfortunately, EMAS is not "the means to all ends" solution for certain uncomfortably short rwys as I had Naively imagined perhaps a better arrester sytem can be developed and certified in another 100 years or so---very fast for the FAA!
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Old 6th Nov 2007, 19:03
  #34 (permalink)  
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Just following up on my earlier post, does anyone know whether the 240m ICAO standards are to be made mandatory by the CAA, or will they remain merely recommendations for the forseeable future?

I'd be really grateful if anyone could shed some light on this.

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Old 7th Nov 2007, 09:37
  #35 (permalink)  
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It stands as a recommendation. However, the CAA are unlikely to OK/Licence any plans for new extensions/Runways without the 240m figure being there.
That's my understanding of the situation at the moment...
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Old 29th Nov 2007, 05:27
  #36 (permalink)  
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cross-checked by British Airways' unplanned research into bogging a B744 at Perth, and my own unplanned research into severe rutting and pavement damage using a 737-800 and a 767-200 of (I forget whom) at (I forget where).

The BA 744 got bogged on RWY 24/06 at YPPH because the capt failed to follow the leading line & turned over the soft shoulder blast protection with the left rear main gear & went straight throught!!! 100% pilot error!
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