“Tower-Contractor 1 EXPEDITE!” More runways tales

“Tower-Contractor 1 EXPEDITE!”

More runway tales...

In the recently published articles entitled, “Airport Tales” and “Mayday. Mayday” - Airport memories 25 years on- the writer has drawn upon personal, hands-on experience to share with readers aspects of airport maintenance that are not usually in the public domain, together with some anecdotes that are entirely unique. This is not for any purpose of self- aggrandisement, it is simply that few have made the transition from a Highways and Airport maintenance related career to that of writing, the latter proving to be a wonderful medium wherewith to share memories that would otherwise be lost as time unfolds. This particular article is likely however, to be the last such piece but even if this proves to be so, only snap-shots of the 'behind the curtain' world of 'live' airport maintenance are revealed.

One of the biggest headaches that airport operators face in relation to aircraft safety relates to the maintenance of runway skid resistance values (SRV's). Runways are constructed and laid-out to provide for reciprocal operations and therefore have two thresholds and two areas known as TDZ's or Touch-Down Zones; this is due to the fact that aircraft take off and land into the wind, rather than with the wind behind or across the aircraft for the purpose of maximising aerodynamic 'lift'. A TDZ is typically 500 metres in length and full runway width, however the predominant area of concentration is 10 metres either side of the localiser (centre-line) by 500 metres (or longer) in length.

When an aircraft lands, a number of functions occur simultaneously or very close to simultaneously; let us imagine a Boeing 747 for this example. Approaching at around 160-180 knots, in full landing flap configuration with landing gear extended, at the point of touch-down the nose comes up and the aircraft settles down; as the main landing cart (all 16 wheels) locks down, the anti-lift flaps or spoilers deploy dumping the mass of the aircraft onto those huge wheels whilst on touch-down, the flight management systems initiate a one-touch-2 second braking moment whilst the aircraft engines are placed into reverse-trust mode. This, together with supplementary braking, causes a considerable amount of rubber to be laid down in the touch-down zones which has the effect, in due time, to substantially occlude runway surface texture and skid resistance values fall accordingly. 

Readers may recall from the article which recalled anecdotes from Damascus in 1999, that the full length of the runways had become compromised by rubber deposits as aircraft had become forced to land deeper and deeper due to SRV occlusion. In fact, a KLM pilot confided to the writer at the time, that were they to encounter rain at Damascus, a diversion to Beirut would have been inevitable on grounds of safety!

An example of Captive Hydrology removing rubber deposits. This was not the actual machine as used on the project concerned.

There are various ways of solving the problem of rubber build-up and the removal thereof, but most involve the closure of a runway which is inevitably costly and time consuming with operational penalties adding to the headache. One of the most effective in terms of time and cost and because there is no requirement to close runways is the use of Captive Hydrology. This is a one-vehicle, one-pass completed process which combines the use of very high water pressure and powerful vacuuming to recover the water and rubber debris. This also has the added benefit of removing FOD'S (foreign object debris) simultaneously. The writer was a one of the pioneers of the technique in airport operations, as a matter of interest.

RAF Brize Norton: Rubber deposits can be picked out from this view.

At RAF Brize-Norton in 2001, we had been tasked to carry out a rubber removal operation during a continuous process at a weekend. 22000 square metres had to be cleaned during what we understood was a 'closed runway' regime and in theory, this would be relatively straight-forward. Where things went wrong was, that on arrival at the control tower for a pre-works briefing, it became 'fairly clear' that the runway was anything but 'closed'. The first hint of which being when this columnist, a VHF licensed RT operator, was handed a radio and call signs were agreed (Contractor 1). The RAF runway was fully-operational this weekend after all! But with Captive Hydrology, we can shut down and vacate a runway leaving it safe to function within minutes and so typically, ATC can call up with something like the following:

“Contractor 1-Tower: Traffic inbound 6 miles longs; vacate runway”

“Tower-Contractor 1: roger that: Vacate runway”

(Sometimes the instruction would include the perhaps euphemistic verb 'expedite'!)

RAF C-17 Globemaster III

But our Austrian operator (Hans) and 'yours truly' got on with things and during the night, we were treated to a variety of military comings and goings interspersed with 'tower-contractor' banter over the VHF radio with no small amount of humour being spared, all of which served to make the night-day shift all the more bearable. But inevitably, something had to go awry; at one point, a call came into vacate, but the call was not heard [this can happen] in which case ATC resorted to a 'highly technical' back-up procedure which basically involved flashing the runway edge lights! EXPEDITE! Barking ones instructions to Hans who panicked, he was unable to get the machine out of operational gear (hydrostatic) so we were limited to 10 KPH forward travel! We nevertheless vacated but the aircraft (a Boeing 757-200 charter plane) then proceeded to follow us down the RET (rapid exit taxiway) en route to stand. 'Hansie' could see the aircraft right up behind us to the extent that once again, 'eye lids were batting at both ends of his physiology', whilst RT banter between ATC, the 757 pilot and 'yours truly' was hilarious! When we were finally able to turn off and the aircraft revved up and passed us, there was a moment of various lights being flashed (by the 757) and time honoured hand signals between the first officer and this columnist who, as he pens this memoir, is grinning and chuckling, 13 years on!

Given the enhanced nature of on-site operational requirements, the pair of us opted to work through without a break and successfully completed our operations in 18 hours (phew). On completion, the writer signalled ATC thus:

“Tower -contractor 1. All TDZ operations fully complete and runway vacated. The runway is yours and incidentally, many thanks for the air-show.”

Back came the reply:

“Contractor 1- Tower. Many thanks; we aim to please!”

There followed our usual de-brief in SATCO's office much of which cannot be related here, however whilst our respective standard requirements were seen through to the letter, the humour was almost aerobatic.

Live runway maintenance operations involve very high levels of planning and concentration on all sides of the contractual relation with all parties being devoted to our mutual primary duty, that of safe airport operations. In 47 years of combined Highway and Airport maintenance works, never was so much fun, happiness and exhilaration gained, from the most dangerous and critically important operations and locations as was gleaned from airport operations at home and overseas, and these will never be forgotten by this now seemingly 'grounded' Asphalt Surfacing Consultant who has embraced semi-retirement with all due alacrity. (edited 16/5/2022)

By

Chris Green

 Beşparmak Media Services

“Airport Tales”

"Airport tales"

By

Chris Green

 

In a recent article entitled “Mayday. Mayday” Airport memories 25 years on, a hint was made to the possibility of further revelations from the writer's core career background, that of Highway and Airport Civil Engineering. This week's article, therefore, relates to a selection of just a few anecdotes of airport maintenance 'incidents' that never made the press. Before embarking on the first of these though, it is important to note that whilst the following is a mere snapshot of what were a fair few 'moments of enhanced concern', these only relate to the writers own career, implying there have been a great many more which there undoubtedly have been; but this has to be measured not only against the vast amount of air traffic movements that are incident-free even during vital maintenance, but also the volumes concerned and the immense complexity innate within 'live' airport maintenance operations.

Long haul flying from a pilots perspective, was once described to the writer by a now retired BOAC/BA pilot, as “hours and hours of boredom, punctuated by moments of sheer panic”. This is not remotely the case for those of us who take possession of a 'live runway' at say 2200 with the imperative of handing it back in a 'fit for purpose' state at 0600 or whatever time is so designated and these can, and do vary depending upon the individual contract. At Istanbul in 2010, main contractor EKO inşaat extended and refurbished the now designated R23/05 runway but this was a full closure regime; nevertheless the $100M contact had to be completed in no greater than a 100 day duration. On one occasion, 'yours truly' looked up and spied a Turkish Airforce C160 Transall aircraft climbing out of runway 36/18 and it was clear that the No 1 engine was 'glowing a bit' (on fire actually!). The aircraft went around and landed safely at the first attempt but it was striking to the writer, that the only passing interest shown, was the attention of the fire brigade whilst no one else so much as batted an eyelid! However, it would be reasonable to suspect that the pilots were batting eyelids at both ends of their respective physiology as the event unfolded!

In Damascus, in 1999 an incident occurred that could potentially have been very serious indeed, although as it turned out, no aircraft came to grief as a result. Damascus International airport comprises of two parallel runways (23/05 L/R) and are (or were then) of a concrete construction. Rubber deposits from aircraft tyres extended between the thresholds of both runways which seriously inhibited vital skid resistance values. 'Muggins' here was charged with carrying out detailed surveys of the runway condition prior to making a project proposal. After all the rigmarole of briefing ATC (rather than the other way around in this instance!) the inspection party got to the threshold of 23L at which point, the writer alighted from the transport, preferring as always to inspect on foot.

Now, with concrete pavements, especially in very hot climates, after a number of years a phenomena can occur called 'corner curling'. Concrete slabs are laid in bays and due to the excessive heat, in time the right angled corners of the slabs can 'curl' or obtrude from the flat slab profile and with continuous aircraft impact, these protrusions can erode and fracture. What should normally happen, is that ground maintenance crews should inspect at least twice a day for FOD's (Foreign Object Debris) but if they had such a regime at Damascus in 1999, it was not regular at all for the threshold was absolutely strewn with nuggets of concrete fragments, any one of which, if ingested into a jet engine OR worse still, been drawn into and thereby trapping a control surface, has the potential to bring down an aircraft with obvious consequences. Witness too, that the Paris Air disaster involving the ill-fated Air France Concorde was the result of a single FOD item, not due to a scene reminiscent of a pebbly beach as the writer was facing here! All hell broke loose as ground maintenance crews were hurriedly scrambled to clear the pavements and effect the repairs. The language employed and the forceful nature of the writers intervention is modestly edited for the purpose of this article! Phew!

AND finally, for the purpose anyway of this particular flight down the memory airway, at London Heathrow in 1990 the contract regime there was that we took possession of the runway at 2200 with a scheduled hand-back at 0600 + 15 minutes max flexibility; but you knew when you took over the runway that dozens of heavy jets were already well on their way, plying their respective routes across the heavens and all were 'fairly keen' to land on time especially the cargo aircraft who operate under slightly different criteria (they carry less fuel!) and so the pressure was always on when working at LHR. It is anywhere, but at London Heathrow, pressure is rather greater.

We were at the stage where we were laying Porous Friction Course which is the final element of the runway surface construction or so it was in those days. This a delicate material to mix and to lay and we have the discipline of completing all laying by 0300 so as to enable the material to cure sufficiently to take aircraft. In 99.999% of the time, there are few or no problems and on this occasion there were no obvious exceptions; we completed and vacated on time and demobilised the shift. The first couple of inbound aircraft landed normally but later in the morning a BA 747 landed and in doing so, it touched down rather deeper than the 500 metre Touch Down Zone and accordingly it had to break somewhat 'enthusiastically' and as it ran over our newly laid material, it was instantly 'under-sealed' as the engines in full reverse thrust, lifted the sticky 'black stuff' leaving carnage in its path!

The runway was immediately closed so that emergency repairs could be effected and there was controlled, measured pandemonium all around! The 747 was out of service for about 9 months whilst the resultant delays and knock-on effects were mounting and mounting as were the costs, which ran into many millions of pounds. The subsequent shift proceeded as normal, but behind the scenes a contractual chess match was being played out which eventually led to BAA picking up the entire tab for the days misdemeanour’s because we successfully 'persuaded them' that it was a specification/design error on their part which could give rise to such events! The truth of the matter was that on the night in question, a vital ingredient had been left out of the mix due to plain old human error! We got away with it in other words; another 'phew'!

Airport maintenance operations were always a favourite activity for the writer during his long career especially as was the case in the latter example, when working with Mick Chalkley who was a very well respected and now retired, Airport Project Manager. I hope that there will be many more such anecdotes to share with our esteemed readers and as always, comments and feedback and your own stories and experiences are always welcome. (edited 16/5/2022)

Chris Green

 

 Beşparmak Media Services

“Mayday. Mayday” Airport memories 25 years on

By

Chris Green

On January 8, 1989, British Midland Flight 92 crashed into the embankment of the MI Motorway near Kegworth in Leicestershire, UK, killing 47 passengers. Seventy-four people, including seven crew members survived this event, some with serious injuries. This crash has become known as the Kegworth Air Disaster.

Flight BD92 was on a scheduled flight from Heathrow to Belfast, Northern Ireland, having made the inbound flight from Belfast to Heathrow earlier in the day. As the plane was climbing to reach a cruising altitude of 35,000 feet, one of the fan blades unexpectedly cracked. The pilots knew that something had happened because of the loud noise and the vibrations. What was not immediately apparent was the source. Smoke had poured into the cabin through the ventilation system and some of the passengers in the rear of the plane saw smoke and flames coming from the 'right hand' engine.

Having declared a Mode 1 emergency, the plane was ultimately diverted to East Midlands Airport. The pilot disengaged the autopilot and flew the aircraft manually but instead of shutting down the malfunctioning left engine (No1), the crew mistakenly assumed that the smoke was coming from the right engine (No 2) and shut it down. They thought they had corrected the problem because they could no longer smell the smoke, but in effect they had left the aircraft without an operating engine at all.

On the approach to East Midlands Airport, the pilots followed the normal routine of pumping fuel into the engine to slow it down. They continued to pump the fuel into the malfunctioning left engine, which caused it to ignite and burst into flames. The crew tried to restart the engine by wind-milling, which means they tried to use the air flowing through the engine to restart the turbine, but the plane was flying too low. When the plane hit the ground after passing over the M1 Motorway it split into three sections.

The fuselage broke into three pieces upon impact into the M1 embankment. Credit: PA

 

 

  

Rescue workers at the scene of the crash on January 8 1989 Credit: PA

On that very night, twenty-five years ago, another airport drama was being played out but with a very different script. In October 1988, a contract to completely refurbish the runway at Luton International Airport commenced with Redland Central Contracting as Main contractor. This columnist was Project No 2 and the project manager was Mick Chalkley, a man already highly experienced in Airport Projects. For the writer, this was his second airport related project: Istanbul International Airport in 2010 was his 21st and final such project.

Airport contracting, especially operating under night closures is to understate, a logistical challenge. At Luton, we typically gained the runway at 2200 and we were contracted to hand-over a sanitised and safe runway at 0600 the following morning. A fifteen minute delay was tolerable; much more could lead to costly diversions and on a couple of occasions, this did actually happen with resultant repercussions. One such incident involved a Monarch Airlines Boeing 757-200 (G-MOND)the details of which are perhaps best left 'hanging in the air' for a future article, save to say to say that both Mike Chalkley and the writer could relate just a few hair-tingling anecdotes!

London Heathrow Airport.

 On the night in question, we could not take the runway at the scheduled time. Rumours were abound that an aircraft somewhere 'was in a bit of trouble' and might need to divert to us. This would be common practice following the declaration of a Mode 1 emergency for the pilots would have requested 'nearest available' divert option. Now from a contractors position, such a delay especially of an open-ended nature, creates just a few headaches. We averaged during the currency of the contract, some 2000 tonnes of asphalt per night; that is the equivalent of 100 return lorry movements quite apart from the logistics pertaining to the transportation of the constituent materials. A delay as was unfolding here, had the potential for significant knock-on effects, however when measured against the outcome of the Kegworth incident, this was insignificant.

Of the 118 passengers on board flight BD92 on January 8^th, 1989, 39 were killed outright in the crash and eight were fatally injured and died later, for a total of 47 fatalities. All eight members of the flight crew survived the accident. Of the 79 survivors, 74 suffered serious injuries and five suffered minor injuries. No one on the motorway was injured, and all vehicles in the vicinity of the disaster were undamaged . The investigation into the Kegworth air disaster determined two things to be the cause of the crash. The first was engine malfunction. The engines powering the aircraft was an upgrade of an existing engine type and had not been adequately field-tested. Human error, as is so often the case, was also at fault with the pilots shutting down the wrong engine.

Mick Chalkley and 'yours truly' went on to manage several subsequent airport projects and we became a formidable duo particularly because Civil Engineering was (to understate) traditionally highly adversarial, and we were very good at that! Between us, we have amassed somewhere around 90+years of Civil Engineering experience. Mick Chalkley has since retired and as the writer amends this piece (16th May 2022) Semi-Retirement has been gratefully embraced for review in 2028!

 

Chris Green

Beşparmak Media Services