Pushback incidents with parking brake set?
 

Has anybody ever heard or know of incidents with damage having occurred when the tug driver attempted to push back or pull an A320/B737 sized aircraft with the parking brake still set? (Please do NOT mention incidents where the brakes were set DURING the pushback.)

The reason I'm asking is that I've recently switched company. At the previous employer it was SOP to allows ask the driver if the brakes could be released, and, only with the brakes released, tell the driver that you are cleared/ready for the pushback.

In my new company there's no such SOP and I hear my FO's (on their stretch) telling the driver that we're ready or cleared for push (with the brake still set) and waiting for the driver to instruct him to release the brake.
I think it's just a matter of time before a driver will start pushing with the brakes still set. Can/will this potentially dame the aircraft or tug?

I hear my FO's (on their stretch) telling the driver that we're ready or cleared for push (with the brake still set) and waiting for the driver to instruct him to release the brake.


This is the way most of my company have done it. The ground crew is in charge of the brakes during push-backs. i.e. they tell you when to release them and re-set them. Thus it it their responsibility to ensure the tug is connected before instructing to release brakes. Ideally, you would have confirmed the tug was connected and all equipment clear before asking ATC for push-back. In your former SOP I'm assuming you have push-back clearance from ATC, then you ask permission to release brakes, and then you tell ground techs you can push. One has to assume that the ground will only allow brake release if the tug is on.

There are shear pins on the tugs/towbars etc that are there to protect if the brakes are still set. My SOP always was, "Flight deck - ground. We are cleared to push, Park Brake is set."
"Release Park Brake," "Park brake released." "commencing push."

There are many ways to skin the various cats, just be vigilant.

RAT 5, thanks for the interesting reply.
Indeed, in 99% of our destinations the flight crew gets ATC clearance for the pushback.

I fail to see how shear pins can avoid damage if the tug/lifter pushes straight back. It might be useful during turns (when max angles are exceeded) or while pulling, but when pushing back in a straight line?

So, I'm assuming you have no knowledge of damage in the situation I described?

Not a pushback, but still an interesting video

I’ve always thought that the pushback was a manoeuvre that had several threats, particularly regarding communications.

Many years ago I was an F/O on a 737 which diverted from Gatwick to Stansted. The handling agents who pushed us back were unfamiliar with our airline. I can’t remember our SOPs at the time but the result was a misunderstanding and the push was started with the parking brake set. The tow-bar broke free of the nose gear and jumped up into the wheel well, causing some minor damage to the gear leg. After an inspection, it was decided that we were safe to depart.

Fast forward several years. My current airline SOP and comms procedure is as described in the original post.

Pilot to Push-Back Crew: Are you ready to push? Clear to pressurise (hydraulics)?
PBC to Pilot: Yes, we’re ready. Clear to pressurise.

Pilot to ATC: Request push.
ATC to Pilot: Push approved, face west.
Pilot to ATC: Push approved, face west.

Pilot to PBC: Push approved, face west.
PBC to Pilot: Push approved face west. Release brakes please.
Pilot to PBC: Brakes released.

After push complete:
PBC to Pilot: Push complete, set brakes to park.
Pilot to PBC: Brakes set to park, cleared to disconnect, awaiting your visual clearance.

So, in summary, the PBC control the releasing and setting of the brakes.

When I suggested that it might be an idea to state that the “brakes were set to park” during the initial contact with the PBC, I was told that this was non-standard and it might confuse the PBC, especially down-route where English is not their first language. On reflection, I have to agree. The SOP works as long as everyone is familiar with the standard phrases but I can still foresee potential misunderstandings if one diverts to an off-line airport.

eckhard: Indeed, pushback should be a simple as possible. Ground crews are of differing qualities in intelligence and english. In you SOP sequence no-one confirms the brakes are set. It was common, if the flight-deck were seated before the tug arrived for the ground crew to confirm the brakes were set before they started putting their hands in dangerous areas around the nose gear. It was their initiative.
I have had occasion where I told ground crew we were ready for push, and before anything else could be said by either party I heard the tug fire up and felt the slightest of nudges. I realised the brakes PDQ and off we went.
I think the answer to 'your idea' of 'being non-standard' is more a 'we didn't think of it so it can't be a good idea'. If you bust a shear pin i can take an age to find another one, in some places, and then what as you miss your slot?

Cagedh: I have to confess I do not know the full design specs of shear pins. I had assumed one scenario for protection was a straight push with brakes set. I have been subjected to shear pins shearing, but the ground crew didn't explain, and it wasn't a brakes On issue.

Moving along, and opening an older discussion: I still advocate the procedure used at some airports. Flight-deck informs ground crew they are ready for push: ground crew ask ATC for Push clearance and then tell flight-deck to release brakes. So simple, less chat, and any complicated local knowledge push back instructions will be between local ATC & local ground crew in their own language. IMHO, introducing an extra link of, perhaps, non-local aircrew, into the communication sequence is increasing the risk of an error. TEM principles would erase that.

a simple and clear check-list will avoid any issue , this should not happen ...

In the company I flew for, the captain was always PF on the ground. (A320)

When I became a captain there many years ago, it was emphasised that we should not use the phrase "ready/cleared for pushback" when the parking brake was still set to make sure that the ground crew would not push too early.

The communication would be:
Pilot to ground: "May I release the parking brake?"
ground to cockpit: "Release parking brake"
Pilot to ground: "Parking brake released. Ready for pushback."

In those (few) airports I've visited where the ground crew takes care of contacting atc and obtaining the pushback clearance, I would tell the groundcrew: "Ready for start. Let me know when I can release the brakes."

Just as it's a good idea to use the word "take off" only when receiving or reading back a take off clearance, it seems common sense to me never to state "cleared/ready for pushback" unless the parking brake is released and the pushback can start without further delay or communication. It seems just as good an idea as it is to wait for the ground crew's "thumbs up" to initiate the after start checklist.

NOT using this sop for pushback, I think, is an incident (or worse) waiting to happen. Why wait for the incident to happen? Iome's Youtube movie shows that it can be a very costly mistake to push/pull with the parking brake set!

(@eckhard: it would have prevented your pushback incident in Stansted!)

Why a red light indicating “BRAKES ON” in the nose hasn’t been installed has been a mystery to me for 32 years now.

It seems clear that there are various airlines with differing SOP's, and probably some with very little guidance. Airlines are flying to places that didn't have jets & tugs until recently. The raid expansion into small fields, and I have experienced it, is that the lower down the sharp end food chain you go the worse the english. It will always be the case that new CP's want to tinker and SOP's for minor moments can be changed subtlety. There is no way all out-stations can be familiar with all the differing SOP's, and in a foreign language. The same ground handlers can look after 10+ different airlines, especially with the growth of LoCo's just in EU. That's 26 different languages after english, and all within a 2.30-3.00hrs flying radius from the centre.
In the air, all over the world, there is standard ATC RT. It is an exam & licence. On the ground, all over the world, there are standard marshalling signals, and the marshalers have to take an exam and be licensed. Surely it is not beyond the wit of ICAO to fill the gap and create a standard RT for pushback. Even taxi instructions have a template. Is it because the communication is not between an ATC agency and the pilots that it is deemed non-critical? Yet we have seen many a major screw up during this manoeuvre; some have been costly.

It is no defence for either party to start the "but you said this," and "I thought you meant that" etc. I go to work to get away from that.

Is our industry not supposed to be proactive. Has it ever even been thought of, a standard ICAO RT? And backed up with GF's excellent idea; especially with the oft occurring no headset pushback, and the low hour never done it before captain.

A320 has this.

Our procedures are.

Confirm with ground crew that checks are complete and tell them brake is set
Get pushback clearance from ATC
Tell ground crew we are cleared to push
Ground crew tells us to release brake
Release brake and tell ground crew ‘brakes released ready for push’.

I think once in 13 years i have had a push commenced before telling them brakes released.. in that case, they saw the light go out but we hadn’t called them yet.

Ground crew calls for brake release and set. First communication always informs GC that the brakes are set, then our language is "ATC cleared the push, standing by for release order/request".

During walk around not so long ago, I observed a tow bar coming loose next door after an apparent push attempt with brakes on. Made quite the noise and the tug driver was struck by a bit of debris. We later learned one of the aircraft's main gear brakes were seized. The driver was rather annoyed.

Experienced tug drivers have told me it is usually quite apparent to them when the brakes are released.

https://d2t1xqejof9utc.cloudfront.ne...jpg?1339176234

'tis amber. But only 30 years and 30 days since the first flight. :E

In which case the argument for standardisation grows. It is mandated that there should be a red anti-collision light to alert to the engines are running. It is mandatory that there are coloured nav lights; even though you can not see them on the ground at night at any major airport, or with great difficulty, in all the other light pollution; and in the air TCAS has taken over from Mk.1 eyeball at night. But these little gems are still there on ALL aircraft. Some have strobes, but are the mandatory or just the good idea of some manufacturers? They were not there originally until someone had the wizz-bang idea that they might be useful. There were adopted and then became mandatory. A bit like Volvos DRL's. They irritated the uninitiated for decades, but were not required. They are now. The raised central brake light, the rear fog lamp, the reversing light.

So why not a 'brake released' light on the nose gear of all commercial aeroplanes? Plus standard push back ICAO RT? There has been a huge number of items & issues in our operation that we take for granted because it's always been like that, and others that we thought a darned good idea during our careers that were then adopted. So why not this. IMHO the argument against good ideas has to be why NOT to do something. rather than justifying doing it. The suggestion of the new idea has already considered that; it invites the reasons to reject it.

The usual answer to that is: cost. No different here.

Maybe 'cuz a nosewheel of a parked aircraft ain't rolled over or sucked anyone in yet?

I could say the same about some pilots I've met over the years. ;)

It is blatently obvious when Nav lights are on. They stand out a mile regardless of lighting conditions. It was always deemed best practice to switch the Nav lights on when the a/c is powered electrically when I was going through my early years training. This best practice seems to be dieing out unfortunately.

I'm stuggling to think of one that doesn't.

B777, B787, A320, A330/340 A350 all have them.

As does the B747

http://c8.alamy.com/comp/BEG7X0/a-cl...hts-BEG7X0.jpg

Actually no, not when taxiing around any major airports at night with light coming from everywhere. Most scary moments I’ve had approaching other aircraft from behind. The Nav-lights are of course better than nothing, but I tend to switch them off during day time as then it’s blatantly obvious where other aircraft are ;) Thought it’d save maintenance some man hours and cost.

You’ll save more by leaving them on all the
time, it’s the cycling on and off that wears them out

Now that is a very very good point.
The only thing I can think of is that were it to be used a sole indicator of whether brakes were set or not you've only got to have an inop bulb and potential disaster awaits...

Here we go again.......

Jimbo2Papa

Not if the bulb indicates "Brakes NOT set", in that case a bulb failure would indicate as if the brakes were set and the ground will contact you to release brakes... even if they are already.

Bae146 NLG Broken off.
 

Aeons ago, I was F/O on a Dan-Air Bae146 at AMS, closed up and ready to go, tug attached with driver in situ, but no comms via the headset.

We became aware of movement of the 'frame and a heavy vibration as the (solo) driver/crew revved his engine to try to push us back with the Park Brake still ON.

This was followed by a very loud BANG and a lurch as the nose of the aircraft sank towards the concrete, accompanied by the continuous sound of the "U/C not locked down below 160 kts" horn which added to the general air of "WTF!"

Following the sudden miraculous appearance of many spectators staring at the obvious damage and the eventual insertion of railway sleepers with padding under the buckled forward fuselage skin, we disembarked the pax in preselected cabin sections, in order to minimise the total weight shift of disembarkation and possible further sudden settlement.

We found out later the damge totalled £250k (late 1980s money) and the tug driver was found not to have made verbal contact nor had he retracted the towbar wheels IAW SOPs, thereby defeating the purpose of the towbar shearpin.

We were immediately suspended, post accident, so off to Duty-Free and buy some grog for our (now) passenger flight home with another carrier.

The only caution I can take from this accident is the advice not to allow one's hand(s) to appear on/above the coaming at this critical time, just in case the groundcrew, who may be operating with a duff headset or external I/C socket U/S, see fingers tapping impatiently on the coaming and interpret it as the open fist of a "brakes-off" hand signal. Not that that was considered a factor in this case. :uhoh:

The modern Boeings have three lights.
Park Brake Set (orange)
Brakes On (red)
Brakes Off (blue)
I think.

What's the difference between Park Brake Set & Brakes On? Is one the selector and the other the brake pads? I hope they also have words and not just colours.
But back to some earlier comments. Some manufacturers have decided in their wisdom after committee meetings and historical events, to spend money, voluntarily, to include these lights on modern a/c; similar to DRL's & hi-level brake lights before they became mandatory. It would seem this is deemed sound investment to avoid expensive screw ups. I suggested it might become mandatory, but on reflection, it could be considered by EASA & FAA not to contribute to flight safety. Any screw up is only a financial penalty to the airline and/or ground handler. When I suggested why it doesn't become more widespread that was shot down on the basis of cost; and yet we are told modern Boeings & Airbuses have them installed, voluntarily. A few bucks above the lowest U$60m price tag seems trivial. On a U$180m hull it is negligible. Seems common sense has a low price threshold.
Have the modern B737 family got them fitted? Remember the cargo fire extinguisher debate. It was not deemed necessary as the original design Class D? was still the same, and it was going to be too expensive to retro-fit the world's fleet of mediums. The debate was caused by an unlawful act by one carrier. However, the design was incorporated, at significant cost, to all new manufactured. And the last cargo fire on the class worldwide was.....? The last attempted brakes on push back worldwide was......?

Just done the Max course....no park brake indicator downstairs.

I can surely tell you from personal experience it was at least last week.

I reckon the combination of park brake light + standard (ICAO) RT would cut down a lot of those incidents.

For the poster who thought it would be a "potential disaster" if the light became standard and then it would be inop for some reason, the A320 MEL states that for this light to be inop, efficient communication with the ground crew should be used. Just the standard RT would go great lengths in adding to safety in those scenarios.

For the moment, I'd reckon that if the crew is always to check the status of the brakes, it would be quite helpful, particularly at the "before pushback" stage since it seems the main difference in SOPs, based on what others have said here, is the initial brake release before push. I.e.: "cockpit to ground, cleared to push, may I release the brakes?" This way it's always the pilot who is getting confirmation of what to do, sort of "leading" the manoeuvre, and avoiding confusion to the ground crew who may otherwise forget or mix up different SOPs (in the case of a handling agent)

BarkingMad,

Great story, if I may use those words, for learning purposes. Thanks for sharing!!

Airstairs, Apu and Self-Maneuver stand!
Love it!

Anyone wants to quality proof the SOP, try it in Spain for a while.
SOP works great if ground crew understands English,

Had a MAD crew do destructive testing on my nosegear last month.
Turned out it is very strong. Pushing!

One indicates that the brake pedals are pressed, therefore brakes are on. The other indicates that the park brake is set. In the case of a Boeing that means pressing the pedals and pulling the park lever on.
In Airbus world the park brakes are set by a rotary switch.

Re: 737, I'm guessing that due to the design, with the nose leg being so short any lights would be so low down as to be next to useless.

The lights are there on other types as an added indication to the tug driver I assume as the headset man is usually stood off to one side out of sight of the lights.

On modern aircraft there should be shear pins at the tow hook attach points which are weaker than the aircraft and will fail when you try to move an aircraft with the brakes set.

OPTION to be installed

I disagree. You started by saying: "cleared to push." If he can hear you badly or he's too quick, the driver can already start pushing against set brakes.

In my original post I suggested that the best communication method would be NOT to talk about the pushback clearance UNTIL the parking brake IS released.

Don't mention the word "Pushback" until the parking brake is released.: Simple, clearer, less risk of confusion, safer!

Comments welcome!

totally agree

Disagree - you have been cleared by ATC to push, ATC have NOT cleared you to release the parking brake, YOU do not release the park brake until ground have told you it is safe to do so, as they are the only ones who can see if it is safe to do so.

Standard call is

Cockpit crew to Ground crew “Confirm all doors checked closed and locked”.

Ground crew to Cockpit crew “All doors checked closed and locked”

Cockpit crew to Ground crew “cleared to pushback” (+ instructions on where/which way to face etc)

Ground crew to Cockpit crew “Pushback to face… (+ repeat the instruction of
where/which way to face). Release parking brake.”
Note: The request to the crew to release the park brake should only be made once “all doors closed and locked” statement has been made. See above.

Cockpit crew to Ground crew “All doors checked closed. Parking brake off. Blocks off
at …..”

@spannersatcx

Hi, you're completely missing the point here.
Obviously I'm not talking about all the other stuff that needs to be done before starting like checklists, ground checks, closing doors, getting start/pushback clearance from atc (or the groundcrew getting it), etc...
The only thing I'm trying to make clear is that it would be wiser not to use the word "pushback/push" or telling the ground crew that you're ready or cleared to do so until the parking brake is released. (After the groundcrew's permission to release them of course, as stated in my previous post. :rolleyes: )

I would hope this gets implemented in SOP's in those companies that don't do this yet. Usually SOPs only get changed after damage is done and lives are lost. THAT is a pity! :ugh:

Why are you so concerned about this? You started the thread asking if anyone knew of accidents during pushback with parking brake set.
I assume you don't know of any, nor the pprune community by the look of it. Certainly Google doesn't.

So it would appear the risk is relatively low, as long as people stick to standard calls and sop.
Perhaps the towbar is designed to give before the gear assembly.
Perhaps you worrying too much about it.

There have been a few examples in replies in this thread: check replies #4, #5, #23 and #29.

A brief Google search found this:
https://www.ntsb.gov/about/employmen...06LA191&akey=1
http://www.aaiu.ie/sites/default/fil...2002_015-0.PDF


Well, perhaps the risk is relatively low and no life was lost... until now. I think the risk can be further reduced by what I'm suggesting, so WHY NOT implement it? (as used to be the case at my previous employer.)

Perhaps... Perhaps not... In case of a pull it seems more obvious that shear pins might add protection, but when performing a pushback?

Perhaps... future will learn... But in the mean time, I will still be worried when in my new company, my F/O, on his stretch, will tell the ground crew we received a pushback clearance before or without talking about the parking brake status. :=