Taxi Fuel Savings - Taxibot
 

TaxiBot Approved To Enter Service With 737 Fleet

by Charles Alcock
November 3, 2014, 11:57 AM -

The European Aviation Safety Agency and the Civil Aviation Authority of Israel have issued a supplementary type certificate (STC) for the TaxiBot aircraft towing system developed by Israel Aerospace Industries (IAI) in partnership with France’s TLD and Lufthansa LEOS. Plans call for the semi-robotic, pilot-controlled system to begin commercial operations with Lufthansa at Germany’s Frankfurt Airport by the end of November.

The initial STC—the first for a system of this type, according to IAI—covers use of TaxiBot with Boeing 737s under FAR 25 rules. Unlike a standard no technical objection (NTO) approval issued by the airframer, the STC covers the use of the equipment for all phases of push back and taxiing to and from the runway. Airbus expects soon to issue an extended NTO for its A320 fleet that would cover the same scope of operations.

Trials of TaxiBot have proven its ability to taxi a fully loaded 737 at 23 knots, which IAI claims is the fastest speed achieved by a taxiing system to date. Rival systems are under development by a Honeywell-Safran partnership and by WheelTug.

IAI claims TaxiBot offers significant savings in fuel consumption and engine emissions. According to the company, a 737 or A320 burns about one metric ton of fuel (1,250 liters) in a typical 17-minute taxi operation. By comparison, the TaxiBot only consumes around 25 to 30 liters for the same operation. An aircraft taxiing under the power of its own engines would emit around 7,040 pounds of carbon dioxide, compared with less than 132 pounds with the TaxiBot.

The pilot retains full control of taxiing, operating the TaxiBot via the aircraft’s tiller and brake pedals, and the system requires no modification to the aircraft. Crews perform coupling and decoupling of the TaxiBot on the taxiway, close to the runway.

In trials conducted by Lufthansa, the airline found that it achieved savings of 37 percent in terms of the time taken to get in and out of airport gates. According to IAI TaxiBot project director Ran Braier, the equipment also reduces the exposure of aircraft engines to foreign-object damage during the taxi process.

IAI has yet to announce a base price for the TaxiBot but said that airlines will achieve a return on their investment in less than 18 months as a result of fuel savings and reduced cost of operations.


(DISCLAIMER: I have no financial interest in the product, it's just an interesting story of a technological advancement in our industry... another one. Keen to hear from those involved with this, progress reports)

Not an engine expert, but don't engines require a warm up time before you apply take off thrust ?

Might save on fuel but what about the impact on reliability and maintenance ?

Also it will be a pain to taxi out to the engine start point only to find out then after start you have a problem that needs you to go back to stand.

It aint broke, dont fixit!
 

A 737 use ca 700kg per hr on grd. NOT A ton on a 17 minutes taxi as claimed falsely!
3 minutes warmup and cooldown time on the Cfm56 is minimum.
All said and done: Hogwash.
Put Your money elswere!

"Crews perform coupling and decoupling of the TaxiBot on the taxiway, close to the runway."

That seems way too dangerous. :eek: And exposing those people to the tremendous noise made by spooling-up jet engines will harm their hearing.

Lufthansa have been quoting typical fuel savings for an A320 of 50kg for a 14 minute taxy out, 180kg for 28 mins.

50kg......wow that's a lot for all the effort required!! :ouch:

@ DaveReid

Lufthansa are _crazy_. I was SLF at an airport yesterday and watched 15+ take-offs Most rotated and climbed at about 15°. The one exception was Lufthansa. That aircraft went airborn way short of any other on same Rwy same conditions. It climbed out at around 30°. Very impressive too.

flynerd, Airline jets normally use graduated thrust; that is, enough power for a safe takeoff plus a small increment.
Under some circumstances, graduation is not permitted and max thrust must be used; great fun for the pilots, esp in a twin which, due to its excess power, will climb away spectacularly.
My company introduced a 20deg max pitch angle for pax comfort when using max thrust :(

There's really no point to opinions supported by guessometrics only on this: the risk/benefit calculation of such a system can be figured out to a few figures after the comma, and both Lufthansa and an airport like Frankfurt or Amsterdam have enough ops engineers and smart bean-counters to figure it out.

Just to contradict myself, I'll take a wild guess that only the very bigges airports with habitual taxi congestion would benefit from a system like this, and in that connection it would be interesting to know if the taxibot is usable in adverse weather, i.e. taxiways that are iced, flooded or covered in snow..

Taxibot systems are welcome additions to airports of sizeable magnitude, not smaller regional types. Anywhere where taxi times exceed 15 minutes could be considered favourably for the Taxibot, however, lesser time to would add more complications and hus add time to the process of departing.
Add to this the fact that smaller airports do not have the infrastructure to return the Taxibot to its next location (e.g. parallel roads for instance clear of taxiway to next pushback location), which in turn requires an infrastructure change far exceeding cost benefit for airlines.

What would we be saving in 17 minutes:
- Normal operation 60kg Jet-A taxi fuel
- Taxibot operation 30kg Diesel(?)

Considering the difference of 30kg is roughly $30, I'm sure beancounters can work out how many pushback/pull movements would break even the Taxibot which costs how much? Add to that the million$ spent in procedure changes, airport layout modifications, crew training, Taxibot maintenance...

Money could be better spent on improving delay reductions using advanced sequencing from gate to runway by reducing holdups for aircraft moving under their own power.

It's also worth considering that it's not just the time spent taxying that determines the fuel burn, it's also the number of stops/starts during the taxy to the runway.

From the point of view of many airports, it's the resulting scope for reducing emissions by aircraft on the ground that's grabbing their attention.

Exactly.

A-CDM is helping in this respect and the eventual goal must be for all departures to have a minimum taxi time straight to the runway for takeoff. If all the needs, positions, speeds, etc. of aircraft both on the ground and in the air are known, then you can have real-time optimisation. Yes, there will be tech problems, go-arounds, RTSs, stand congestion and the like but clever software should be able to adapt to that.

If an airport is planned to run at X movements per hour, there’s no insurmountable reason why the majority of those movements should suffer any delay in taxiing. It just needs a holistic approach where all operations can be varied for the common good.

Must admit I much prefer this solution: WheelTug - Wikipedia

"Taxibot" adds no weight, draws no power from the a/c, and requires no modifications. On the flip side, it will need to be connected and disconnected (which will not help to shorten turnaround time). I can see taxibot working for long-haul flights. "Wheeltug" on the other hand adds weight, and draws power from the a/c, but won't affect turnaround times (they claim turnaround times can even be shortened). I can see this working for short-haul aircraft that spend more time on the ground. Then there is also a third contender, EGTS - electric taxiing system. Introducing the future of aircraft taxiing that plans to install electric motor in the main landing gear, from 2016 (honeywell is involved here), they don't target long-haul a/c

As others pointed out fuel savings are maybe not the biggest selling point here, there are other factors, reduced engine wear, less risk of foreign object damage, no hazardous engine blast, fewer emissions, ever shorter turnaround times, that may be just as important. Thinking about savings, pushback by truck costs anywhere from 100-250 usd in the US and Europe, up to 500 USD in some less efficient airports in Asia. Maybe there will also be fewer pushback tug accidents....they're also expensive https://www.google.com.vn/search?q=p...ed=0CAYQ_AUoAQ

I see some new issues though, like....ground controllers will have to keep track of "taxibots" returning back to the terminals....

Fuel SAving during taxy :hmm:
To me it is the very last thing to do when you have exhausted all other means to achive savings :E

Since the various strategies available for saving fuel aren't dependent on each other, there is no reason why they shouldn't be pursued concurrently.

Really 50kg? Wow thats not light at all. Not sure how I feel about this :ouch:

I assume the APUs are cheap to service and use no fuel.

The other means dont require investments.

like retrofitting winglets, lightweight seats, etc...