I suppose Airbus is going ahead with the electric taxi idea

[Check Airman]

Airbus A320 Electric Taxi FIRST TEST! - YouTube

[Wizofoz]

Good idea in princliple- but I would have thought just using tugs to position for takeoff would have been cheaper than fitting every aircraft with the gear, both from a complexity and weight POV.

[RR_NDB]

Hi,

Considering the motors will be powered by gennies even after landing thus not requiring the dangerous dangerous batteries :} i think is a good approach that "has future".

Time will tell.

PS

Li Ion for me now is :mad: during some time :{

[Piltdown Man]

How do you convince the plonkers who refuse to shut down one engine "for elf'n'safety" reasons that shutting two engines will be OK? And will there be a reverse gear? Will the Campaign ever allow such a device (to be used economically?). How much will an airline be charged to do a DIY tow? Will it have enough grunt to get up at the (soon to be closed) taxi-bridge at TXL fully laden? Will ATC play the game and give you two three/four minutes notice of actual take-off time so you can fire up the engines?

Not withstanding the above, I think it will be good idea.

[Oriana]

How do you convince the plonkers who refuse to shut down one engine "for elf'n'safety" reasons that shutting two engines will be OK?

You can tell 'the plonkers' :hmm:it will mean not taxiing using asymmetric thrust.

[PAXboy]

I suppose Airbus is going ahead with the electric taxi ideaIf they think that they can do so commercially and that it will give them an advantage = Yes.
(merely a pax observing through the window)

[Basil]

Reversing? Expect to see a few sitting on their tails :{

[lederhosen]

The technology and business model are nearly there. However there are some open issues for example airport infrastructure. Not all airports have the space to cope with aircraft needing to start and warm up their engines in the runway vicinity. Ultimately ways will be found, but there is some pioneer work required.

[Mr Rowntree]

where are the reversing mirrors fitted?
:ooh:

[kbrockman]

I suspect this will initially be used to taxi to the stand after touch down, no need to worry about reversing or space/time to start up the engines and in most cases the APU is going to have to be switched on anyway after landing, might as well make good use of it.

Later on maybe also useful before take-off, certainly at the smaller airports that mostly use open ramp space which don't really need push back anyway.

I have a vision of the pilot with his arm out of the window looking back over his shoulder ,skilfully reversing like a real trucker while at the same time hearing the all known BEEP BEEP BEEP... :), we also might have to reintroduce a real wheel again in the future iso the yoke or stick.
http://www.flightglobal.com/blogs/aircraft-pictures/10059small.jpg

[Momoe]

The idea behind is this is save fuel by NOT using the engines, APU powers the electric motors and engines would be started well clear of the terminal in time to complete engine checks prior to receiving take off clearance.

Safer as well as should be no ground crew near aircraft when engines are started, also no delays waiting for a tug.

Pushback would presumably have ground crew advising, although even quite modest cars have TV camera's in addition to RV mirrors, add a couple more on the wing tips and it's not quite so scary.

Some airports will give bigger cost savings than others but Airbus wouldn't have progressed with this if there wasn't a good chance of commercial success, Lo-Co carriers will probably bite their hand off as it means they can reduce airport expenditure even more

[Busbert]

Wheeltug.gi are offering a nose wheel based solution and tested it on B737 even on snow and ice. They are proposing free retrofit with the airlines splitting the savings. A320 family system in the pipeline. It will be interesting to see who will be first to market... Interesting presentations and video on the Wheeltug - it seems that the nose wheels can generate enough traction...

[Stone Cold II]

Good idea in principle. Who's going to tell me about a fuel leak after engine start though? Couple of years ago I had a fuel leak on engine 2 and only knew about it from the ground crew who were monitoring the start? Aircraft was AOG for a week down route.

What about tailpipe fire as well?

It would be great not having to worry about a tug for push.

[Smudger]

1. Don't forget to take the blanks out before you try to start the engines

2. The departure holding point is a bit late to find out you have an engine problem during or after start

3. It isn't April 1st is it ?

4. Whatever next ... harummpphhhh

[Stone Cold II]

Wonder if they could put some tiny camera on the belly so the flight crew can observe the engine start.

[Busbert]

Agree to all 4, but remember that those who control the purse strings know the cost of everything and the value of nothing. If the figures stack up, then it will happen, and if it gives a commercial edge, everyone in the short haul airline business will want them. No new bit of tech is risk free, and as the benefits can be quantified they get talked up.

[USMCProbe]

If you fly out of small airports and only taxi 3-5 minutes (3 minutes is CFM warmup time) then these have no use and you are carrying around extra weight. If you are flying out of busy airports and your taxi time is 15-45+ minutes these will save enormous amounts of fuel, especially on 737 and A320 sized and smaller aircraft that fly a lot of legs. Great idea.

Who is monitoring your engine start? At a busy airport, the 7 aircraft behind you. They will be eating your smoke if you have a tailpipe fire.

[jossurf]

USMCProbe
Fully agree but I'm doubtful its endurance will outlast >10 minutes

[Evanelpus]

Reversing? Expect to see a few sitting on their tails

Easy, peasy. Press CTRL/ALT and P together and it will automatically reverse, simples!

[oxenos]

Will it work on the conveyor belt?

[fmgc]

The departure holding point is a bit late to find out you have an engine problem during or after start

Who's going to tell me about a fuel leak after engine start though?

Most of us are taxiing out on one engine now, so how is this any different with regards to these points?

[busav8r]

"Who is monitoring your engine start? At a busy airport, the 7 aircraft behind you. They will be eating your smoke if you have a tailpipe fire."

USMCProbe, really? At night?

[busav8r]

"Most of us are taxiing out on one engine now, so how is this any different with regards to these points?"

My present company also tried to recommend and implement the one eng taxi out procedure but after several problems they quit the idea (thank god). Some of those problems could result in serious mechanical problems and maybe a safety concern.

Other than several fuel leaks during eng starts which most of them resulted in returning to the gate for troubleshooting, I once had what I would call a beginning of an eng fire due to a broken eng starter. At night and without any indication on the EWD, the problem was early detected by the ground technician after he spotted lots of smoke coming from the engine. Fortunately other than a broken starter no other damage resulted to the engine, but I wonder what would had happened if such problem had occurred while on the holding position...

So I wonder why there are people still adhering to these practice. But maybe that is just me...

[PT6A]

easyJet have been reviewing this idea with Airbus for sometime, the main drawback at present is the weight of the motor.

[ChrisVJ]

In terms of cost I would think a few small cameras, don't have to be HD, would be just the ticket for monitoring start up. (Yes, I know, aviation standards!)

Don't know what a tug costs per push but if there is no airport mandate ("HAVE to have a tug") then I imagine the savings would really stack up over time.

I am a little surprised no one has arranged for wheels to be spun up for landing, but maybe the hit on the tires each landing isn't worth it, might be another saving there?

Just thinking out loud.

[Dan Winterland]

Monarch used to start the number 2 engine of their DC10 just prior to take off. After a couple of failures because it hadn't warmed up properly, they gave it up as a bad idea.

[TURIN]

A lot of airlines already start engines with no ground crew present. So, in their case this concept rids them of 2 or 3 ground staff and the tug. Over time this will save them millions. Whether it will save them enough to offset the weight and additional maintenance costs of the drive unit remains to be seen.
Reversing off the gate is not new. Bae Jetstreams did it for years.



Posted from Pprune.org App for Android

[fmgc]

So I wonder why there are people still adhering to these practice. But maybe that is just me...

Well many airlines, including Monarch without a DC10, are taxiing out on 1 without incident.

So I wonder why there are people still adhering to these practice. But maybe that is just me...

I thought this was a common practise on the rear mounted engine aeroplanes, DC9s and MD8X?

[Slasher]

Given the potential pitfalls of electric taxi I'd rather Boeing
be the first to deliver such a system rather than Airboos.

[busav8r]

A320F FCOM PRO-NOR-SOP-08 p1/6 :
...If, during the engine start, the ground crew reports a fuel leak from the engine drain mast, run the engine at idle for 5 min. If the leak disappears during these 5 min, the aircraft can be dispatched without maintenance action. If the leak is still present after 5 min, maintenance action may be required before the flight...

The statistics in my present company shows that in every 10,000 flights, about 2 airplanes need to return to the gate for troubleshooting due to this particular problem. The average delay caused by such problem is about 1 hour (due to maintenance).
Experience also shows that the problem may be solved if we try to shut down the eng and then perform a restart after that. But again, for that we need ground crew supervision.

In most cases those fuel leaks may be due:
- VBV gear motor particularly impacted by cold soak condition
- leak from shaft seals o-ring under cold soak condition
- HMU fluorocarbon seals do not provide an effective sealing at low temperature if the engine is not warm.

But I am not really surprised when I hear pilots saying that there's nothing wrong with the single eng taxi out... after all that's the actual industry tendency: try to save money at all costs.

For me, other than trying to save millions, this may represent a concerning attitude in terms of safety :ugh:

[Basil]

To avoid tipping on to the tail as one brakes down from reversing, a brake fitted to the nosewheel would automatically discontinue retardation as the wheel came off the ground.
You heard it here first and I shall defend my patent rights :)

[kbrockman]

Basil,

I'm not 100% sure but I think that once you put the idea out in the open before patenting it , it becomes public information and can no longer be patented.
So no millions$ for you I'm afraid.

[Checkboard]

Pilot operated tiller reversing out is still common around Europe & Australia - with the help of a Power Push System.

Jetstar A320 Push Back - YouTube

[t1grm]

If you are flying out of busy airports and your taxi time is 15-45+ minutes these will save enormous amounts of fuel, especially on 737 and A320 sized and smaller aircraft that fly a lot of legs. Great idea.

Should save a fortune at Schiphol then... the taxi is as long as the flight! ;)

[flyingchanges]

There would be no tipping if the nose wheel were doing the braking.

[panda-k-bear]

There's also a certain amount of anticipating legislation related to NOx emissions and noise here as well. Since airport communities are pressuring governments over local air quality (I know - there's more gas coming out of the bus that takes you to the airport...) and engine noise, this seems to be a reasonable solution. More especially so if, in the longer term, you can do away with the APU and use a hydrogen fuel cell in its place. Back of a fag packet calcs show the fuel saving on a taxi out at CDG or AMS vs. the penalty of flying around the dead weight on a 500nm sector to be well worth it.

Given the potential pitfalls of electric taxi I'd rather Boeing be the first to deliver such a system

Only provided it doesn't spontaneously combust... :E

[grounded27]

I suppose Airbus is going ahead with the electric taxi idea

This is nothing new. What would make you think airbus is going along with this. Probably to the contrary Luftansa and the manufacturer trying to get the STC approved, Airbus may be involved but I have seen no press release to the fact. It has been quite quiet. If it becomes popular and airbus is not involved Airbus or the customer will have to pay for rites to the STC for the product to be fitted on new aircraft. I have no knowledge of a CAA buying off on this yet.

Ok got off my butt and googled it Luftansa technic and L-3 have only performed ground test's to see if the system will work, that is a long way off from making it happen. They are not the only players there is another system being developed for the a320. What I found...


DLR Airbus A320 Taxis on Electric Nose Wheel: #evworld (http://evworld.com/news.cfm?newsid=26060)

VIDEO: L-3 and Lufthansa get moving with e-taxi demonstrator (http://www.flightglobal.com/news/articles/video-l-3-and-lufthansa-get-moving-with-e-taxi-demonstrator-365815/)

[Ixixly]

Just a thought, but could the Cabin Crew not be used to "Observe" on engine startup for any abnormal smoke/flames etc... on engine start up? Just a simple addition to procedures to have one standing by with a view of the back of the engines Flight Crew makes some kind of announcement "Cabin Crew standby for engine start", a crew member walks to a position where they can see the engines through the windows with another crew member upfront positioned with access to the intercom who can relay any signals from the observing CC a second call "Engine start complete" from the Flight Crew allows CC to resume normal duties.

Obviously for wide body aircraft one down each aisle perhaps required?

[USMCProbe]

Some airlines single engine tax in and out every flight by SOP. Every time they start or shut down the second engine, there is no ground crew to monitor. NONE.

I started flying jets in the military that had to be manually started. I had quite a few hung starts, hot starts, no ignition, etc. In 1800 hours I had probably 15 or 20 abnormal starts.

Flying for airlines the last 17 years and 10k hours, I have had one abnormal start (no ignition), and it was maintained to less than optimum standards in SE Asia.

This includes 727,37, 57, 67, 77, and 320 series.

I will take my chances with starting with no ground crew. I see it as minimal risk.

[busav8r]

USMCProbe, first of all sorry for my english, as it is not my first language (not even the second language), but I will try to do my best.

Apparently we have both the same military and civilian background, except the fact that I have been flying Airbuses for the last +12,000 hrs.

After reading your last post, I can't agree with you. My standards in aviation since day one has been SAFETY in first place. ALWAYS. I don't give a **** if my management tries to push me to fly with less fuel of what I think it is reasonable for safety reasons (wx, traffic delays, etc) or tries to convince me to save fuel doing single engine taxi outs as a regular practice or even tries to persuade me with fuel saving bonus. And to be honest I never had a single problem with such attitude. And do you know why? Because I always try to use good common sense and I always comply with the SOPs. In this particular case with the Airbus SOPs.

For me there's no such thing as minimal risk or low risk or almost no risk, as long as the SOPs requires for a certain procedure or to follow a certain recommendation. Unless of course the Airbus SOPs are different in the other side of the world (which can be possible).

During the last 12,000 hrs I had some fuel leaks during engine starts. Some of them I was able to recover after some time delay (3 or 4 minutes running the engine at idle), some after shutting down the eng and then restart it and some I had to return to the gate for troubleshooting. One time I had to change the airplane. Like I said in a previous post, a few years back I also had a broken eng starter which made me abort the eng start not because I had any indication on EWD, but because I was timely advised by the ground personnel.

I also know a case which happened to a spanish carrier (Vueling or Click Air maybe ?) a few years back, when they had an engine fire during the 2nd engine start up (during push back). The crew were able to shutdown the engines and order for an emerg evac without too much trouble. The fire crew was right there and minimal damage resulted from the incident. Again thanks for the timely advisory from the ground crew and also the location of the incident, that company for sure saved thousands of $$$.

For me does not make any sense and it can be considered a bad or even an unsafe attitude to disregard what is written in the SOPs, even tough the chances to happen something is considered to be minimal or residual. For some reason it is in the SOPs.

But like someone just said in a previous post, I don't see any problems to perform single engine taxi outs as long as I have a means to supervise the engine start ups. And I believe video cameras could be an excellent idea...

NOTE: For the CFM it is considered a fuel leak when the amount of drops of fuel exceeds a certain number. For instance, any leak below 60 drops per minute it is not considered a fuel leak and the acft can be dispatched without restrictions. But for instance if the fuel leak lies between 60 to 90 or even more drops per minute and depending on the origin of the problem (HMU, shaft seals o-ring, etc), some restrictions may apply (the aircraft may be allowed to fly for a few sectors). But in most cases troubleshooting is required.

[cockney steve]

As there is a necessity to run the engines up to operating-temperature before takeoff, that "waste" thrust can be used to assist the electric taxi scenario. no reason why a single ground-controller could not monitor engine starts from a fixed, designated "start area" is there?

Delays after engine-start are not going to save fuel , so the only saving is going to be between Gate and "light-up" points.

IMO the saving is more wishful and theoretical thinking than an actual ,practical saving. hope i'm proved wrong!

[DozyWannabe]

I'd imagine the reason they're testing it is to prove or disprove the system's real-world usefulness...

[bubbers44]

It seems the B787, once it gets it's battery problem resolved would be the perfect airplane with their massive electrical power to use electric motors to taxi and push back. The APU would get them to a point when engine start could give them a few minutes to warm up and save tons of fuel. Also hydraulic power could be used if more efficient.

Now we have cars that can park themselves so why not have airliners that can push and taxi by automation with someone, ramper or pilot to monitor?


I hate automation that is required, deteriorating pilot skills, but using it to save labor costs and fuel is in the near future.

[bubbers44]

The power back could actually be monitored with cameras very carefully from a camera verifying all was clear from a company observation tower. In 10 years I think this will be the normal way of doing things.

[clark y]

Maybe Airbus could reduce the size of the normal brakes and add extra brakes in the form of motor/generators. Just like trains and some electric cars.

[bubbers44]

CY, how about spinning up the main gear before landing to reduce rubber loss on touch down. We had a nose wheel spin up on our Citation Jet in the 70's. It was a flying whore house with video, etc in Alaska during the oil find. They could land on gravel strips and bleed air spun up the nose gear so it was not as likely to throw rocks into the engines. The landing lights had screens in front of the light.

Unfortunately we got it after it came back to California. That is how they got their rocks off in Alaska. Maybe it will help prevent burning rubber on our airliners here.

[Dusthog]

Eventually the batteries used for taxi must be recharged by the engines. Besides, there is also a cost with carrying the weight of that extra equipment. I can only see some kind of advantage with this system for short flights with long delays on ground before take off, but then you should have had a slot before leaving the gate :D