Friday, 30 May 2014

Railway upgrading. Men pay the price of mice.

The latest issue of the excellent fortnightly "Rail" announces that the planned budget of £1 billion for the electrification of the main line from London to Bristol ,Cardiff and Swansea is already looking like being exceeded.

The culprits? Disagreements with councils over road closures and the old familiar suspects newts, bats and now dormice. The newts and bats are fresh from having delayed the reopening of the second bore of the short Wolvercote tunnel, essential for the new link between Oxford and Marylebone, by the best part of two years.These species seem to crop up remarkably frequently in debates about,- that means opposition to,- HS2 and other road and rail projects large and small. One has to wonder if they are that rare and endangered after all. They certainly seem to be much less so than is the notion of building to meet the transport and travel needs of the 21st century and future generations.

Thursday, 29 May 2014

A Plane, a Yacht, and no Nimrod. What now?

Two recent disappearances have had a common thread,-or rather two. Both are pertinent to civil and military aviation and navigation.

Both the MH 370 and the yacht Cheeki  Rafiki and their occupants have disappeared mid ocean. Both have required air searches and both saw their locator devices fall short of the robustness, range and longevity they needed.

The ideal search aircraft would have been the Comet 4- based Nimrod. The MR2 maritime reconnaissance version was scrapped in 2009 as an economy measure by the Brown government. The current coalition finished the job by cancelling the much reduced order for 9 of the substantially rebuilt and re-equipped MR4s . The MR 2 did its job well and the MR4 form gave it a 6,900 mile range. Like its predecessor the Mk 4 had the ability to transit quickly from its base to the search zone and then thanks to a big wing,- originally designed for the underpowered early 1950s DH Ghost engined Comet 1 to enable it able to land slowly and take off reasonably quickly on hot "Empire" routes, -  it was able to loiter slowly for several hours on much reduced power. The turboprop stub winged Electra based Lockheed Orion, the only alternative now available and of which the UK has none, is much less capable especially in the fast transit area.

There is no question of reviving the Nimrod. The way ahead therefore has to be approach the problem from the other end by increasing the capability of the systems to match the search capability available. This means firstly boosting the capabilities of satellite tracking systems so that the location of any crash or sinking is immediately known. This should not require any messages, pings, handshakes or whatever being transmitted from the tracked aircraft or vessel.  In any case the locator equipment on aircraft and vessels should be incapable of being turned off . In addition, the longevity and range of locator systems from aircraft / vessel right down to individual lifejacket size should be substantially increased. Much of the technology is already available and should not be difficult to develop further.

There is potential for a positive common legacy from these two tragic and very different events.

Friday, 16 May 2014

The Mathematics and Physics of Runway Capacity and Utilisation.

-Like London's Heathrow, Manchester, Hong Kong, Singapore and others ,Dubai Airport has two parallel  runways.

-For 90 days from 1st May until the end of July Dubai will be operating with only one of its two runways open at any time. Runway resurfacing and taxiway additions and improvements are now essential so the airport has simultaneously taken all its bulls by the horns.

-As result movements have been reduced by around 25% throughout the period.

-Prior to May 1st inbound holding delays of up to 40 mins were common especially in the peaks Departures were also frequently held awaiting slots.

-One might have expected that with runways reduced by 50% and movements by only 25% things would have got worse.

-In fact they have got noticeably better.

There is a potentially rich seam of study here for physicists, statisticians and others. Somewhere in the mix must be critical points up to which everything goes reasonably well and beyond which it suddenly goes over a cliff and collapses in a heap. The Gatwick people whose achievements with a single runway are legendary may have a view. So would those who controlled Hong Kong's Kai Tak with the added complication of the famous late sharp right hand turn and the frequent nailbiting gamesaver "Expect late clearance to land".

There is another interesting issue here about airport design. Dubai's layout with its main terminal to the west of both runways requires much crossing of the western runway by traffic using the eastern. In theory this does not reduce runway movements/capacity as the crossing aircraft do so in the unusable gaps immediately after the landing or departing aircraft has passed across their nose. The same applies at Heathrow where aircraft from Terminal 4 or the Cargo or VIP areas using the northern runway have to cross the southern one to do so. The home and other frequent user carriers may normally be able to confidently accomplish the crossing in the time allowed. Others may be much less quick off the mark (controllers will know who they are but consistency is never total) and require more of a gap before the next movement on the runway to avoid the further capacity- reducing complication of people having to hit the go-round or abandon takeoff buttons.

In all this ,- and notably the debate about a possible 3rd or even 4th runway at Heathrow,- the location of the terminal(s) is crucial. On a two runway airport the terminal complex needs to be between them. Put a terminal north or south of the 2 runways Heathrows T4 style and you've got a time wasting problem. Add a third runway and another terminal between runways 2 and 3 is required. All three runways should not be seen as serving both terminals unless the third is so far offset from the previous two that a taxiway can be built from it well clear of the thresholds of the other two enabling access to the original terminal area without crossing or interfering with the intervening live runways. It's possible but would require a lot of time and money spent on additional  taxiing.

By the same token even at the present Heathrow where every additional slot is worth millions, all aircraft to and from the southern side of the airport should routinely be restricted to the southern runway,- and always have been. In the way is the endless debate about and refusal to accept or impose mixed mode operations as a matter of course. That debate could go on for a while yet.

Meanwhile Dubai, its planners and operators have firmly grasped the nettle of the 3 months single runway operation and made it work from day one. The cynics have been put to flight. Some say "Ah, but they've cut back too much". They ignore that hidden critical point, the right side of which the planners have stayed regardless no doubt of urgings to increase the risk. They got it right.

 Back now to the mathematicians, statisticians and physicists to produce winning formulae for the world.