Anyone got some T-cut?

[furrybeast]

https://i.redd.it/9pm2yzgnnoz01.jpg

[rationalfunctions]

Apparently it was being towed to the gate. Given the significant number of wingtip collisions over recent years (towing or taxiing), is it time to consider tech that can detect wingtip obstacles and alert pilots/handlers?

[GKOC41]

San Francisco

[DaveReidUK]

Tip of Aer Lingus Plane Wing Hits Concrete Wall at SFO; No Injuries Reported (https://www.nbcbayarea.com/news/local/Passenger-Plane-Being-Towed-at-SFO-Makes-Contact-With-Wall-483521901.html)

"A commercial jet that landed at San Francisco International Airport on Wednesday afternoon hit a concrete wall while being towed to a gate, according to an airport spokesman".

Towed to a gate? Passengers reportedly stuck on board for an hour.

[Hotel Tango]

Towed to a gate?

A common event for certain gates at certain airports in the USA.

[jetfour]

My Ford has efficient proximity sensors! Ok, it will be more complex on an aircraft to tug situation - but surely not impossible. Commercial opportunity for someone!

[llondel]

For some reason I looked at the picture and thought 'SFO'.

The tech exists for collision avoidance, it probably wouldn't weigh too much either, but the logistics of getting it installed on everything that needs it would be a massive job (although every successful project has to start somewhere). You've got to retrofit the aircraft, having first determined that it's going to work satisfactorily, then find a way of communicating with the tug, possibly via radio as it's short range, then you have to retrofit the tugs. I guess if it's radio based then retrofitting tugs is easy, a new box on the dash with a big red light on it and a power cord. As it's only intended for low-speed ground operation the certification process may not be too bad.

You still wouldn't catch all of the incidents though, only the wingtip ones. Way harder to stop a wing leading edge from hitting something if the Mk 1 eyeball has failed. Thinking here of the recent incident slicing off a tail fin - that was inboard of the wingtip.

[NutLoose]

is it time to consider tech that can detect wingtip obstacles and alert pilots/handlers?


They have them, they're called the MK 1 eyeballs.

[bnt]

One passenger in the terminal got some really close-up pictures of the wingtip, followed by dozens of media requests to use them:

https://twitter.com/Ivan_DrawGo/status/999415491675357184/photo/1

[Hotel Tango]

I note that Aer Lingus operate both the A330-200 and -300 series. Both types share the same wingspan of 60.3m. However, the 300 is 4.60m longer. I have no idea if it makes any difference to how the tug initiates the turn into the gate but would be interested to know from someone in the know.

[n5296s]

It's a VERY tight space there. The photo is actually taken from the short-term car park, which is what the wing tip has hit.

Several years ago I was picking up my wife and just as we were about to get in the car, a tug managed to create an entanglement between a plane it was pushing back, and the Qantas 747 that spends all afternoon and evening parked in a corner - in this same place. As far as we could tell nothing had actually hit anything, but they couldn't figure out how to undo the situation without making it worse. I kept an eye on things when I got home and the plane did eventually depart several hours later, presumably after an inspection.

[TopBunk]

If Aer Lingus park round the back of International Terminal A where BA parked when I flew the B744 for them, I can confirm it's pretty tight round there when taxying with a good look out on both sides required (not as tight as taxying onto JFK Terminal 7 stand 3 or 9, but still).

Under tow though? Complacency? Poor training? Who knows...

[DaveReidUK]

I note that Aer Lingus operate both the A330-200 and -300 series. Both types share the same wingspan of 60.3m. However, the 300 is 4.60m longer. I have no idea if it makes any difference to how the tug initiates the turn into the gate but would be interested to know from someone in the know.

Interesting. This was an A333.

[pattern_is_full]

https://www.youtube.com/watch?v=ry81Exmgq9s

[Cynical Sid]

Wonder if they used a tub of Vaseline to ease it out.

[Exit Strategy]

Apparently it was being towed to the gate. Given the significant number of wingtip collisions over recent years (towing or taxiing), is it time to consider tech that can detect wingtip obstacles and alert pilots/handlers?

You dont need technology, the only requirement is a set of eyes and the common sense to stop if you dont like what you see.

[rationalfunctions]

You dont need technology, the only requirement is a set of eyes and the common sense to stop if you dont like what you see.

Unfortunately something is going wrong with either the MK 1 eyeballs or 'common sense' if there are ongoing taxiing and towing incidents. Agree with llondell that it would likely have some complexities with retrofitting and interfaces, but if a lightweight solution is available then surely worth it rather than paying out insurance + reputational damage?

[A4]

What about a temporary attachment? You (somehow!?) attach proximity transmitters to the wingtips / tail - simple strapon or clamp - and have the prox receiver in the tug. No need to retrofit at $xx,000,000, just a local kit to get used repeatedly on multiple aircraft.

You’re welcome........:p

A4

[AirUK]

The amount of times I've seen those 'wingmen' in the US waving their batons (basically to say 'keep 'er comin'') as we pull onto stand, whilst looking everywhere BUT the wingtip... I expect that's what happened in this scenario.

Towing onto a tight stand is common in the US. EWR is another place where they do this.

[DaveReidUK]

If Aer Lingus park round the back of International Terminal A where BA parked when I flew the B744 for them, I can confirm it's pretty tight round there when taxying with a good look out on both sides required (not as tight as taxying onto JFK Terminal 7 stand 3 or 9, but still).

The photos appear to show he was being towed on to G91, which is the innermost stand in the 45° angle between International Pier G and the parking garage/International train station.

GE suggests there is approximately 120 feet between the curved yellow stand lead-in and the station piers at the closest point - half an A333's wingspan is 99 feet ...

[mickjoebill]

Wonder if they used a tub of Vaseline to ease it out.
Are you referring to something in the frame at the end of the above video?

mjb

[sb_sfo]

The photos appear to show he was being towed on to G91, which is the innermost stand in the 45° angle between International Pier G and the parking garage/International train station.

GE suggests there is approximately 120 feet between the curved yellow stand lead-in and the station piers at the closest point - half an A333's wingspan is 99 feet ...
You're right, Dave, and as he was about 20 feet off the lead-in line, the math works out just about right.

[roybert]

What about a temporary attachment? You (somehow!?) attach proximity transmitters to the wingtips / tail - simple strapon or clamp - and have the prox receiver in the tug. No need to retrofit at $xx,000,000, just a local kit to get used repeatedly on multiple aircraft.

You’re welcome........:p

A4

A4 Are you suggesting that the aircraft stop on the taxiway to have these clamped on sensor installed then taxi or tow to the terminal. Not a practical solution. Some one had the proper idea with a wing walker and eyes on task.

[One Outsider]

My Ford has efficient proximity sensors! Ok, it will be more complex on an aircraft to tug situation - but surely not impossible. Commercial opportunity for someone!
Yes, because an aircraft is just like a car and at IKEA you can buy rubber thingies to put on the tip of things so you wont bump in to them.

[MurphyWasRight]

A4 Are you suggesting that the aircraft stop on the taxiway to have these clamped on sensor installed then taxi or tow to the terminal. Not a practical solution. Some one had the proper idea with a wing walker and eyes on task.
Although I have to agree that this 'should not happen' if people are paying attention the fact that they still do suggests that additional tech might be useful.

I don't believe additional sensors are needed, just think "ground ops collision avoidance" with each aircraft transmitting it's current (GPS assisted) speed, location and orientation.
A central computer could then issue alerts for AC to AC or AC to fixed obstacle proximity using a static map of the facility.
For towing tugs would also need to transmit/receive warnings.
The tug can probably determine (powered down) aircraft orientation using angle sensors at both ends of tow bar, that would still leave open someone entering incorrect AC type.

Of course unless every baggage cart and boarding ramp was active things could (and would) still go wrong.

[DaveReidUK]

I don't believe additional sensors are needed, just think "ground ops collision avoidance" with each aircraft transmitting it's current (GPS assisted) speed, location and orientation.

Ironically, the aircraft in question would in fact have been doing exactly that.

[visibility3miles]

bnt
Should the tow driver follow the pair of white lines painted on the ground in front of the airplane?!?

Maybe they're there for a reason...

[BEagle]

Looking at the image from the car park, which shows the alignment of the towing vehicle pretty clearly, I'm wondering whether the driver / wing walkers understood the phenomenon of 'swept wing growth'?

When the VC10 entered RAF service, there were a lot of educational posters showing the hazards associated with towing swept wing aircraft....

Training?

[RickNRoll]

...

Training?
How much training do these subcontractors of subcontractors get?

[DaveReidUK]

Should the tow driver follow the pair of white lines painted on the ground in front of the airplane?!?

Maybe they're there for a reason...

Yes, the white lines are there for a reason - they delineate the airside roadway that runs along the back of the Golf stands. Following those when towing an aircraft would have had an even worse outcome. :O

As a general rule, white lines are for landlubbers, yellow ones are for aircraft.

Here's G91, courtesy of GE:

[bolthead]

Crikey! Going to need no. 1 man ( oops, or woman or in-between ) driving the tug to get a wide-body out of there unscathed.

[Start Fore]

Or maybe someone who wasn't flipping burgers last week.

[visibility3miles]

DavidReidUK

Thank you for the explanation.

I stand corrected.

[c_coder]

A4 Are you suggesting that the aircraft stop on the taxiway to have these clamped on sensor installed then taxi or tow to the terminal. Not a practical solution. Some one had the proper idea with a wing walker and eyes on task.


I thought possibly a semi autonomous quadcopter. It hovers 100 feet above the aircraft and acts as a remote camera platform for manoevours in tight spaces.

[smilr]

I thought possibly a semi autonomous quadcopter. It hovers 100 feet above the aircraft and acts as a remote camera platform for manoevours in tight spaces.

Best perhaps to mount sensors or cameras directly to the buildings in question. No need to operate a drone or modify / add sensors to aircraft.

[BAengineer]

Here's G91, courtesy of GE:


That centreline track for the stand has to be the daftest one i have seen - not surprised that they have accidents. If you want to put in zigzag lines like that then best you restrict the stand to narrowbodies.

[Chris2303]

I assume it has been moved?

If so, how did they do it?

[DaveReidUK]

I assume it has been moved?

If so, how did they do it?

Carefully ? :O

Aircraft returned to Dublin on the day following the incident.

[Pugilistic Animus]

Maybe winglets are a MEL Item

[BAengineer]

Maybe winglets are a MEL Item

It's a CDL item - you can have one removed and just tape up the holes.

[Pugilistic Animus]

Thank you BAengineer!
That makes more sense to put it in the CDL. Speed tape, of course?

[DaveReidUK]

https://pbs.twimg.com/media/DeIIU4MXUAAfhLg.jpg

https://twitter.com/Michaelkelly707/status/1000374999084093442/photo/1

[Rwy in Sight]

It's a CDL item - you can have one removed and just tape up the holes.

What does CDL stand for?

[tdracer]

What does CDL stand for?

Configuration Deviation List - basically the MEL for the aerodynamic surfaces - access hatches, winglets, that sort of thing. Many (me included) tend to say MEL when we really mean the CDL.
I did a flight test one time on a 747 that had been configured for a 'worst case' CDL dispatch for some other flight test conditions. The FMC struggled to do speed changes because the aircraft drag was so much higher than normal - it kept undershooting the speed target (which was part of my test conditions).

[Ian W]

As BEagle said there were a lot of warnings with aircraft like the VC10 where the pivot point is not the center point of the wings. The result is what is called 'swept wing growth' or 'delta growth'.

This is in Skybrary as a warning section:

https://www.skybrary.aero/images/thumb/Wing_Growth.jpg/600px-Wing_Growth.jpg

All the aircraft involved in these occurrences were, like most modern large transport aircraft, swept wing types that are subject to a phenomenon known as ‘swept wing growth’ or ‘wing creep’. This occurs during a turn when the wing tip describes an arc greater than the normal wingspan due to the geometry of the aircraft and the arrangement of the landing gear. It is one of the reasons for the manufacturers' cautions usually found in the Flight Crew Training Manuals and can be well illustrated by a scale model of your particular aircraft. Although the effect is less noticeable at moderate curvature of turn, any turn results in some ‘swept wing growth’ that will erode the perceived wing tip clearance.

See Skybrary Wing Tip Clearance Hazard (https://www.skybrary.aero/index.php/Wing_Tip_Clearance_Hazard)

[Cynical Sid]

There were some 'imaginative' solutions using sensors and drones a few posts back. But no one had the idea to use automated tugs. Hook it up, press a button and let a central computer do the clever stuff. So long as the software is not written by Tesla, it could work.

[BAengineer]

Already happening Sid.

I'm not allowed to post links but if you do a Google search for: automated-aircraft-moving-at-heathrow ATI21 and click on the first link you will see exactly what you are proposing :ok:

[wiggy]

Just my two pence worth - all this talk of drones, automated tugs, sensors etc is all very well and is great “Blue Sky” thinking but from a airline CEO/CFOs point of view it is not about avoiding ground incidents, it is about making them affordable...and some of you are not thinking through the cost vs. Benefit analysis behind all of this.

It’s all about the cheapest short term option - if that is hiring and firing wingwalkers and paying the insurance premiums then you are not going to see companies spend large sums spent on technological solutions.

[Ian W]

Just my two pence worth - all this talk of drones, automated tugs, sensors etc is all very well and is great “Blue Sky” thinking but from a airline CEO/CFOs point of view it is not about avoiding ground incidents, it is about making them affordable...and some of you are not thinking through the cost vs. Benefit analysis behind all of this.

It’s all about the cheapest short term option - if that is hiring and firing wingwalkers and paying the insurance premiums then you are not going to see companies spend large sums spent on technological solutions.

And the cheapest solution is to make that gate single aisle only - although the airport might not think so.
I am surprised there are no regulations on gate size and geometry vs aircraft wingspan, length and undercarriage geometry.

[MurphyWasRight]

Quote:
Originally Posted by wiggy https://www.pprune.org/images/buttons/viewpost.gif (https://www.pprune.org/rumours-news/609235-anyone-got-some-t-cut-3.html#post10161273)
Just my two pence worth - all this talk of drones, automated tugs, sensors etc is all very well and is great “Blue Sky” thinking but from a airline CEO/CFOs point of view it is not about avoiding ground incidents, it is about making them affordable...and some of you are not thinking through the cost vs. Benefit analysis behind all of this.

It’s all about the cheapest short term option - if that is hiring and firing wingwalkers and paying the insurance premiums then you are not going to see companies spend large sums spent on technological solutions.
And the cheapest solution is to make that gate single aisle only - although the airport might not think so.
I am surprised there are no regulations on gate size and geometry vs aircraft wingspan, length and undercarriage geometry.
Of course a large constraint on any solution is who pays for it, both directly and inderectly (reduced capacity etc).
That combined with "acceptable risk" (aka insurance rates) likely means there will be no improvement seen in foreseeable future.

Regulators probably will not see this problem as a passenger safety risk, at least until someone manage to puncture a fuel tank.

[Bksmithca]

Already happening Sid.

I'm not allowed to post links but if you do a Google search for: automated-aircraft-moving-at-heathrow ATI21 and click on the first link you will see exactly what you are proposing :ok:

BAengineer

Had a look at the site that you suggested. These tugs aren't automated as they still have a person walking beside them with a wireless controller. Big thing I noticed is that they are electric.

[wiggy]

BAengineer

Had a look at the site that you suggested. These tugs aren't automated as they still have a person walking beside them with a wireless controller. Big thing I noticed is that they are electric.


The device BA is using on some LHR pushbacks is a Mototok product ....and as you say they are not automated/automatic, they are controlled and driven by the accompanying handler.

Claimed advantages are manpower and environmental.

[Ian W]

BAengineer

Had a look at the site that you suggested. These tugs aren't automated as they still have a person walking beside them with a wireless controller. Big thing I noticed is that they are electric.


There is no reason that they could not be automated and know the precise path to take a particular airframe on each gate while scanning to ensure nothing has intruded on the required space for the aircraft path. Robotics is getting better all the time, whether robots or 'autonomous tugs' can cope with the mix of events on current ramps would need to be demonstrated, It is only a matter of time.

Short video (https://d2v9y0dukr6mq2.cloudfront.net/video/preview/r523hCLrlixf2j868/automatic-orange-robots-move-around-the-factory-warehouse-on-the-floor_hizrtqevil__SB_PM.mp4)

https://spectrum.ieee.org/robotics/robotics-software/three-engineers-hundreds-of-robots-one-warehouse

[wiggy]

Robotics is getting better all the time, whether robots or 'autonomous tugs' can cope with the mix of events on current ramps would need to be demonstrated, It is only a matter of time.
...and only when cost vs. benefit equation falls in favour of the robot....

Out of interest if a robotic tug dinks a wall with a wing tip ( and it will happen) who will get the blame/picks up the tab????

[MurphyWasRight]

Out of interest if a robotic tug dinks a wall with a wing tip ( and it will happen) who will get the blame/picks up the tab????
Don't know about the tab but the sweeper will pick up the tip :)

[surely not]

Amazing that there are comments on here suggesting you go from flipping burgers one day to driving a tow/push back tractor the next. That's a bit like suggesting the next time an aeroplane crashes that the pilot was flying a drone one day and Captain of a wide body the next!
The GHA have a hierarchy on ramp jobs and driving a push back tug is only for experienced staff because oddly enough the GHA know it is a job that requires experience and competence.
The last GHA I was with had a 3D simulator that push back drivers had to master before being licensed to drive a push back tractor. This was configured with 4 different backgrounds of stands at the airport, including the 2 that were considered more challenging. On completion of their training they were licensed initially for narrow body aircraft, and only when assessed by the trainers as competent did they move on to additional training for wide body aircraft. Your airline will also have sent your auditors to check the training of your GHA, and push back training and licensing is always covered.
The drivers also have recurrent training every two years.

The other issue is that whilst the centreline is there as a guide, it isn't necessarily relevant to all aircraft types cleared to use the stand. Sometimes there will be a dotted line to follow for certain types that required a wider turning circle, but that is down to the airport operator to arrange.

[BAengineer]

I can see the attraction of a fully automated tug but I dont see that the technology is really there yet and aircraft stands have all kinds of vehicles driving across and equipment scattered around so it would be difficult to come up with an automated system that could account for all the variables for a possible collision.

[Ian W]

I can see the attraction of a fully automated tug but I dont see that the technology is really there yet and aircraft stands have all kinds of vehicles driving across and equipment scattered around so it would be difficult to come up with an automated system that could account for all the variables for a possible collision.

There is a controlled lack of discipline on many ramps as anyone who has studied them will know. However, a robot tug only needs to confirm that the cleared area for the gate and aircraft wingspan _is_ cleared. the rest of the circus can carry on outside that area.

As for costs all the tugs would be around the same, probably not costing a lot more than a standard tug. If they were fully automated then you could reduce manpower and that will rapidly repay the capital cost of the tug. However, it will have knock on effects as the pushcrew are also often 'volunteered' to be ramp snow clearers so that pool of employees would need to be replaced. Robots would not be a one for one replacement.

Responsibility for software faults is always going to be an interesting issue,. Normally, the software is factory then site tested with the 'customer' representatives witnessing or even writing their own tests. When that acceptance test is signed off by the customer they have taken responsibility for the operation and potential errors of the software. There will be some residual support and maintenance from the supplier but the customer has taken responsibility for the operation and functioning of the software. (As a lot of you will have exercised my software in the past, I am rather glad of that :8 )

[BAengineer]

I'm not convinced there would be a massive saving in personnel. You would still need someone to put the chocks in, plug in ground power, A/C etc. - if you dont use the tug crew then you need someone else. Also its difficult to count all the times that the tug crew avoid a collision or delay by moving some steps or a baggage trolley out of the way which if there were no crew the automated tug would simply have to stop (possibly blocking the taxiway) and wait for someone to be dispatched to remove whatever was causing the delay.

[Cynical Sid]

Another advantage of an automated system is that the controlling computer can know the movement requirements for every aircraft. So that can be optimised much more efficiently in theory. And why not add other systems into it too - luggage and buses for example.

[wiggy]

Are you under the impression that “controlling computers” aren’t already in use in the centre that co-ordinate ramp operations, and also aware that things like Start up times and associated runway slots can change at the drop of a hat?...and that’s just the departing stuff.

An ideal arrival stand plan, perhaps in part already generated with the assistance of a computer be stuffed by a jetty breaking down....it’s something along the lines of a tactical plan never surviving first contact with the enemy....and once it goes off plan the human being comes into his/her own.

Most of the problems we see on the ramp aren’t down to a lack of planning, they are down to resources being stretched so drum tight (probably due to some algorithm) that there is no flex in the system to cope with anything going off plan...fully automating the current process (even if possible) with the current level of resources won’t suddenly improve the ramp “experience”.

[Ian W]

Are you under the impression that “controlling computers” aren’t already in use in the centre that co-ordinate ramp operations, and also aware that things like Start up times and associated runway slots can change at the drop of a hat?...and that’s just the departing stuff.

An ideal arrival stand plan, perhaps in part already generated with the assistance of a computer be stuffed by a jetty breaking down....it’s something along the lines of a tactical plan never surviving first contact with the enemy....and once it goes off plan the human being comes into his/her own.

Most of the problems we see on the ramp aren’t down to a lack of planning, they are down to resources being stretched so drum tight (probably due to some algorithm) that there is no flex in the system to cope with anything going off plan...fully automating the current process (even if possible) with the current level of resources won’t suddenly improve the ramp “experience”.

And that is why operations on an airport are event driven rather then deterministic. A late wheelchair, a minor fault on start up. flight crew or rear crew delayed by previous late arrival, a push crew with a delayed aircraft so next aircraft also delayed etc etc. Although padding can allow for some of these it starts getting expensive and reduces gate utilization. After a day of various Traffic Management Initiatives all gating plans become wishful thinking.

[Cynical Sid]

Are you under the impression that “controlling computers” aren’t already in use in the centre that co-ordinate ramp operations, and also aware that things like Start up times and associated runway slots can change at the drop of a hat?...and that’s just the departing stuff.

An ideal arrival stand plan, perhaps in part already generated with the assistance of a computer be stuffed by a jetty breaking down....it’s something along the lines of a tactical plan never surviving first contact with the enemy....and once it goes off plan the human being comes into his/her own.

Most of the problems we see on the ramp aren’t down to a lack of planning, they are down to resources being stretched so drum tight (probably due to some algorithm) that there is no flex in the system to cope with anything going off plan...fully automating the current process (even if possible) with the current level of resources won’t suddenly improve the ramp “experience”.

Anything that is planned in advance is going to break. An automated system should be able to dynamically work out the most efficient way to handle operations as it goes on. ATC would be a good example of this technology. The system does not fall over just because someone appears late or early.