And one more thought on what was wrong:
There was far too-short a period for closure. In the hours available during closure, the contractor must:
adjust markings/lighting
mobilise equipment onto runway
remove asphalt ramps from previous night
if needed remove light fittings
milling out old asphalt
laying new asphalt
compaction
cooling
possibly laying another layer and cooling
if used, temporary grooving
if needed, cut runway lighting slots and cores
if needed, install light fittings
lay asphalt ramps
adjust markings/lighting
demobilise equipment from runway
runway safety inspection
re-open
The typical minimum time is 8 hours, and it usually does involve some rescheduling of aircraft on some days. The pressure from the commercial mangers (and most non-engineering airport management) is that the airport must be kept open and no flights can be disrupted. The two goals conflict, and with an overbearing airport general manager and a weak airport engineering manager, the wrong goal can take precedence. The closure time at BRS was,
AFAIK, 6 hours.
With all the peripheral activities required, the actual asphalt laying part of the job within the 6 hour timeframe is very short. This has the effect that (a) many more days of construction are needed, which increases the number of aircraft exposed to these constrained operations; (b) the lack of time forces shortcuts in the works needed to leave the runway in a safe condition; and (c) the quality is poor meaning that the next runway rehabilitation occurs sooner.
Turning back to the Statement from Bristol International Airport (09/01/09). They claimed that they
engaged the leading expert designers, engineers and contractors in this specialist field. Standard industry practices were followed
I don’t think it is relevant if the contractor is experienced in these matters. The experience of a contractor is that of delivering their product close enough to the specification and as cheaply as possible so as to make a profit. They are not airport engineers, nor are they going to overrule the superintendent/consultant engineers on technical matters. The contractors are used to lots of silly ideas in specifications, and one more isn’t going to phase them. If they are given an overly tight timeline, then they’ll simply try to meet it.
And the claim that ‘standard industry practices were followed’ is a subtle alarm bell. You see, the industry of the contractor is that of the ‘road asphalt industry’; there is no such thing as an ‘airport asphalt industry’. All across the world, asphalt comes from contractors who work on roads and highways with only the occasional job on airports. Even if a contractor has surfaced several airports before, the majority of that contractor’s staff, quality controllers, systems, and operators have gathered their expertise from the road sides of things. There are subtle differences between roads and airports. I’m sure the contractor was following standard industry practices of his own ‘road industry’, but what was needed was for the airport engineers to adjust those practices to airport requirements.
One of the reasons that I am positive about CAP 781 is that it contains a number of those subtle differences.