[Alfresco]

In a bid to control air pollution and to help airlines save fuel, Delhi's IGI airport operator is all set to buy TaxiBots, which are pilot-controlled semi-robotic machines.

In a bid to control air pollution and to help airlines save fuel, Delhi’s IGI airport operator is all set to buy TaxiBots, which are pilot-controlled semi-robotic machines. The TaxiBot will pull the aircraft from parking bays to the runway with the engines switched off, according to an HT report. Moreover, only when the aircraft reaches the runway starting point, the ignition will be turned on for the take-off. The airport operator said that these bots will be only used for departing flights. According to DIAL (Delhi International Airport Limited) officials, during certification trials, the cost of fuel used during taxiing by the bots was brought down by 85 per cent.

An officer was quoted in the report stating that a Taxibot will be driven to an aircraft stationed at the apron area, which is preparing to take off. Then the plane and the Taxibot will be attached. The Taxibot will hold the aircraft’s nose wheel and will lift it slightly. Following this, the plane’s pilot will transport the aircraft from the terminal gate to the runway without switching the aircraft’s engine on. To enable warm-ups and technical checks, the engine will be turned on only a short while before the take-off, the official added.

Lufthansa was the first to use it commercially.


More details:

https://www.financialexpress.com/inf...s-why/1251896/

https://en.m.wikipedia.org/wiki/TaxiBot

http://www.taxibot-international.com

[libranof1987]

This is good in a way that it reduced the fuel bill for the airline.

However, the turnaround time is bound to suffer:

a) attaching, navigating, de-attaching from the airplane from the terminal to the runway is going to take longer than if the aircraft powered itself

b) Taxiways at most major airports today have a queue so airports are going to have to either maintain more taxibots than expected takeoffs in a particular period, or have the aircraft wait

Both these factors will increase the turnaround time for the aircraft. Given that major airports are poised to face an infrastructure crunch (increased traffic vs. ground capability), neither airports nor airlines would want aircrafts spending more time on the ground than in the air in the interest of a lower fuel bill.

Of course, detailed numbers over a considerable period could help understand the true savings.

[sandeepmdas]

Originally Posted by libranof1987

a) attaching, navigating, de-attaching from the airplane from the terminal to the runway is going to take longer than if the aircraft powered itself

Totally agree with your views except this one. Function-wise, the taxibot acts as an extended version of the towbarless-version of the pushback tractor (airplane tug), which is ubiquitous. Attaching/detaching a taxibot is unlikely to take more time than attaching a towbarless pushback tractor. Navigation (taxiing) is pilot-controlled, means the pilot is the driver. The taxiing speed is 23 knots as claimed, the same as the current taxiing speed in good visibility.

[AlphaKilo]

Originally Posted by libranof1987

This is good in a way that it reduced the fuel bill for the airline.

However, the turnaround time is bound to suffer:

...

Originally Posted by sandeepmdas

Totally agree with your views except this one. Function-wise, the taxibot acts as an extended version of the towbarless-version of the pushback tractor (airplane tug), which is ubiquitous. Attaching/detaching a taxibot is unlikely to take more time than attaching a towbarless pushback tractor. Navigation (taxiing) is pilot-controlled, means the pilot is the driver. The taxiing speed is 23 knots as claimed, the same as the current taxiing speed in good visibility.

I second sandeep. Having seen this in action in almost all major airports in Germany, I can confirm that this is as quick as the older taxiing if not faster. Usually, the Pilot already when being pushed back, gets the clearance to taxi to the holding point, so there shouldn't be any delay as the pushback equipment is the same taxibot.

The earlier methods for smaller jets used to have ground starter equipment attached and it has happened in Chennai international that the ground started equipment failed and the Parking space was blocked until a new starter equipment was brought in. Almost all currently flying aircrafts have on-board starters leaving the ground starter equipment almost redundant.

IMHO, having experienced the skill of our ground staff (in Indian airports), I expect some lethargy and carelessness but that is no different to the current situation. Atleast, when the pilots themselves are controlling the bot they would have the sense not to scrape other parked aircrafts.

[Jeroen]

The one thing they need to deal with is engine start and running through the check lists. Engine start is a little more cumbersome and time consuming on a plane than on a car. Now you end up doing this on a taxiway with planes behind you.

What and or how is the actual control of the tug done? It must require some modifications on the airplane.

But it certainly is an interesting concept. Are you sure they are doing it at all German airports? I don't think so.

[Rahul Bhalgat]

Interesting.

The Taxibots (and in good numbers) need to return to the apron area / terminals. So these will necessitate separate "return taxiways" for the Taxibots.

The airport operator will charge extra for Taxibots and let us hope that these charges will be lower than the fuel saving. Or else it will be just a means of additional revenue for the operator.

[GTO]

What kind of a monster engine does a TaxiBot have, to be able to pull a commercial airline full of passengers?

[ariesonu]

Originally Posted by GTO

What kind of a monster engine does a TaxiBot have, to be able to pull a commercial airline full of passengers?

The first one has already arrived at Delhi. I saw one this morning. Still awaiting commissioning though.
A tractor is able to pull a loaded plane easily but having-said-that TAXIBOT will do STOP-&-START for multiple times which a tractor may not be able to perform.

Regards-Sonu

[AlphaKilo]

Originally Posted by Jeroen

...
But it certainly is an interesting concept. Are you sure they are doing it at all German airports? I don't think so.

Not in all but in all major ones like FRA, EDDM etc.. But here the bots are not controlled by the Pilot rather a ground operator does that, leaving the pilots to focus on the start-up procedures. I hear from my friends who fly heavy for Lufthansa that their start-up procedures have been adapted to suit the new bot based taxiing. Some cheaper airlines even do the start-up checks at the ramp itself rather than enroute and some let the Pilot flying to focus on checks while the other drives the bot.

There seems to be no standard procedure yet. Also, there is the option available to opt out of bot taxiing too. I am not fully aware of the nuances of the clearances but this is the info I have from my friends with wings.

[GJ01]

If the Aircraft engines are turned off, will the other systems run using on-board Auxiliary power? For Eg: The Air conditioning.

I have noticed this on multiple flights that when the aircraft is at the gate, the AC systems are powered through the on-ground Aux power supply (I assume). The on-board AC cooling then goes off till the plane is airborne. You may have noticed a lot of passengers fidgeting with the AC knobs, as suddenly the cooling is stopped. I may be wrong on how this is managed, but I thought that the cooling while on ground is either managed by a terrestrial power supply when at the gate and then using engines when airborne.

If the AC gets switched off and there are delays while taxiing to the runway, the cabin may turn out being quite uncomfortable. Aviation experts can correct me.

[saket77]

Originally Posted by GJ01

If the Aircraft engines are turned off, will the other systems run using on-board Auxiliary power? For Eg: The Air conditioning.

If the AC gets switched off and there are delays while taxiing to the runway, the cabin may turn out being quite uncomfortable. Aviation experts can correct me.

I'm no expert in aviation, but just as you said, the air conditioning at ground may be run by the APU or the Auxiliary Power Unit on the aircraft, along with powering many other electronics like instrument cluster & gauges, until they are eventually taken over by the power generated by the engines when they are running. Aircrafts with APU have alternatives to receive electrical and pneumatic power from ground equipment, wherever possible.

Regards,
Saket.

[Jeroen]

Originally Posted by saket77

I'm no expert in aviation, but just as you said, the air conditioning at ground may be run by the APU or the Auxiliary Power Unit on the aircraft, along with powering many other electronics like instrument cluster & gauges, until they are eventually taken over by the power generated by the engines when they are running. Aircrafts with APU have alternatives to receive electrical and pneumatic power from ground equipment, wherever possible.
.

Yes, just about all commercial jets have an APU that is perfectly capable of handling the AC and all aviation system whilst the main engines are not started yet. Depending on design (and sometimes ambient temperature) you have to power down the AC in order to start the engines. As soon as the engines are started they will supply power and air to the AC and all electrical and electronic system.

There are a few aircraft (mostly older) that are out there whose APU might struggle to power the AC in very hot temperatures though.

And of course, APU sometimes just break down. Not a terrible big deal, in nearly all cases the plane can still be dispatched. But as soon as the ground power is disconnected you will be without AC until the engines are started. All electrical and electronic system are run of the batteries.

Jeroen

[Motard_Blr]

Originally Posted by GTO

What kind of a monster engine does a TaxiBot have, to be able to pull a commercial airline full of passengers?

https://en.globes.co.il/en/article-l...tem-1001012106

800 BHP hybrid engine, according to the article. This sounds like a lot just to taxi an airplane but a fully loaded A320 weighs nearly 90 tonnes and a 777 is nearly 250 tonnes!

[BoneCollector]

Apparently the Taxibots have started functioning since last 40 days at IGI Airport, New Delhi. Details here - https://www.thehindubusinessline.com...mpression=true

The move to save the environment is gaining momentum at the Delhi airport, the busiest airport in the country. The airport has completed 100 TaxiBotings in about 40 days (TaxiBots take an aircraft to the point of take-off). In comparison, it took Frankfurt airport about two years to touch 400 TaxiBoting full missions.

Without the robots, an aircraft has to be tugged by a ground vehicle to the Tug Detach Point (TDP), which is normally reached within 1.5 to 2 minutes. Following this, the aircraft has to switch on its engines and taxi to the runway. Starting the engine early means that the aircraft not only has to use expensive aviation turbine fuel (ATF) but that this also leads to both noise and air pollution as carbon dioxide is released into the atmosphere.

According to Ashwani Khanna, Consultant to the project, it is estimated that the 100 TaxiBoting missions at Delhi airport have saved about 20,000 litres of ATF that would have contributed to about 54,000 kg of CO2 to the atmosphere.

[itwasntme]

Very happy to see this being used in IN. As long as a limited number of TaxiBots do not hamper pushback, this is a great idea saving fuel, limiting noise pollution near the PTB, lowering chances of accidents/injuries among ground engineers / staff and reduces FOD incidents near the bays/bridges.

I also believe DIAL (IGIA) has limited Tug Detach Points (TDP) in the T3 apron areas which already limits pushbacks. Used judiciously these should enhance times and speeds.

For the experts, can these operate under CAT III (B/C) or are these strictly 'VFR' weather vehicles?