The way pilots fly their aircraft can have a significant effect on the economics, fuel consumption and environmental performance of their airline. Many airlines and Air Navigation Service Providers are working on Constant Descent Approaches (CDAs) but to do these it is necessary to have well motivated pilots, good operating procedures and efficient ATM procedures.
Particularly on long flights, the pilots have many more things to do than just flying the aircraft. The tactical decisions they make on the day with regard to fuel load, payload, routes and altitudes, descent profiles and the deployment of flaps and landing gear can all affect the bottom line economics. In a lecture given to the Royal Aeronautical Society’s CEAS 2009 Conference last month, Captain Hugh Dibley described the work done in the past to improve operating procedures, the influence the flight crew can have over the fuel used, and some of the possible improvements in the future. In one example he showed that a fuel economy campaign and improved procedures produced savings in the order of 8%. Some recent simulation work done by SAS has shown that CDAs and optimised procedures could produce comparative savings of 18.4%. And even minor changes in operation can save at least 1% at no cost – in comparison, one engine manufacturer currently spends over £800,000,000 per year in Research and Development to improve consumption by 1%. The paper also shows how some airlines were able in the past to reduce their fuel burnt by nearly 10% virtually overnight.
Obviously Flight Management Systems (FMS) have enabled pilots to operate much closer to the optimum than hitherto, therefore future savings will not be quite so
dramatic. Nevertheless there are many minor improvements that can be made to the basic flight procedures. The first is to ensure that the best information is made available and presented in a way that is easily useable on the flight deck. The next is to examine each of the flight segments (planning, taxi, take-off, climb out, cruise, descent, approach and landing) to see what improvements can be achieved. Even small changes to these, and also to industrial agreements, can have surprisingly large effects when aggregated together.
Finally, ATM procedures and systems need to be designed to assist efficient aircraft operations. There is more to this than just CDAs. SESAR has as its environmental goal a 10% reduction in emissions. It is hoped that much of this will be achieved by optimising each flight’s trajectory. En-route this should not be so difficult, but around airports, where complicated noise routeings and traffic patterns tend to interact, new tools to assist controllers and pilots will need to be developed. Some are already available or being trialled with success:- Required Navigation Performance (RNP) departure and arrival procedures, satellite navigation systems, better sequencing tools, airborne spacing systems, CDAs and such features as brake to vacate will all have their part to play.
But central to all this will still be the way that pilots use these on each flight. Read Captain Hugh Dibley’s lecture on the subject and find out what can be done. At the end of his paper he asks why airlines do not use the FMS Required Time of Arrival (RTA) facility to avoid lengthy holds – it is extraordinary to have an aircraft fly for 13 hours from Hong Kong and then hold because it is too early to land before a time which had been published by the airport years in advance! Equally, I find it extraordinary to see aircraft flying over central London, at least 10 miles from touchdown, with their gear down, burning fuel unnecessarily, making far too much noise and polluting the environment…
Download Capt. Dibley’s paper here and his presentation here.
I’ll try again, my first effort seems to have disappeared into the aether..
Phil, I agree it is awful watching inefficient draggy approaches. We live in North London more than 15 miles from touchdown at Heathrow (westerlies) (abut BNN 130/10). Until only a few years ago sudden loud approaching aircraft noises were common, either the occasional Concorde returning from a rare non-US trip, or… the Russians, an IL86 way below the profile and with the gear down ALREADY! They seemed to have acquired some new SOPs along with their new A320s.
As for pilots not using the FMS’s RTA function, not many aircraft actually have it, but any semi competent crew could achieve the same result to an acceptable accuracy if ATC asked them to do so, but they don’t. There are two main reasons:
1) You need a lot of distance to make a real impact (see my blog piece on flying high or low in early October), about 500 miles to be effective, and ATC just isn’t that connected, yet.
2) Not only, but ATC just doesn’t handle big speed changes well. I served a short term as a consultant to NATS during the summer of 2008, when you will recall fuel prices were heading north of $130/barrel. Many operators started telling their crews to slow down, to cries of anguish from the Ops Room. I was surprised, surely the filed speed tells you what is happening…? Not a bit of it, the UK’s data handling system, base on a 1970-s mainframe design, throws away all that stuff, and assumes a 737 always flies the same speed… Eventually doubtless trajectory management will sweep all these cobwebs away, but I doubt I will even be an able bodied passenger by then. Meantime, it just underlines what I have long believed, that 95% of SESAR’s improvements can be had for 5% of the eye-watering cost. There is more information in the average crew flight plan than ATC knows what to do with, and it is available now down a phone line without fancy data links.. (have I said this before?)