I was watching WN ramp ops yesterday @ BWI and had the following question:

After the marshaller crossed his wands to indicate the aircraft should stop, the marshaller held up his left wand in a horizontal position, and held it there without moving for at least 10-15 seconds. I do not recall seeing this at any other ramp ops.

After searching around, I found this:


I assume the marshaller was indicating to cut the engines. However this document (Canadian) and another military one I found shows that the arm should move from side to side and not remain stationary.

My question is:
1) Am I correct in matching what I saw to the diagram?
2) How much variation is there among marshalling signals worldwide, and is it ever a source of confusion? Unlike airport taxiway markings, this seems to have some leeway in interpretation/implementation
3) Aircraft in Canada apparently do not have to stop at all since they did not include a stop signal in the above  

Thanks
BWI757

[Edited 2006-04-18 17:54:04]

Quoting BWI757 (Thread starter): 1) Am I correct in matching what I saw to the diagram?

Probably not. Pilots will cut the engines without cues from the ground crew when pulling into the gate. The cut engines signal is generally only given when there is a problem. As for what you saw, I can't be certain what it means. Maybe he was being lazy and indicating chalks in or ground power connected with one hand? Did the pilot give any signal?

Quoting BWI757 (Thread starter): 3) Aircraft in Canada apparently do not have to stop at all since they did not include a stop signal in the above

Second row down, first signal on the left.

It is an informal signal to the pilots to stay on the brakes until the chocks are in.

Another one, often seen, is to stretch the arms out horizontally with the thumbs pointing down. This is e.g. used if two people were beneath the plane on pushback and one is still in the danger area, so that the pilot will know that he is not yet clear to taxi.

Jan

Quoting Ilikeyyc (Reply 1): Probably not

It is amazing how many different variations of mashalling signals there are, especially when you consider it is supposed to be a standardized system.

That signal you saw is indeed the set or hold brakes signal. When the aircraft arrives, typically the engines are cut immediately. The Captain then signals to the marshaller that the engines have been cut by waving his hand above the dashboard. The marshaller, still holding his brakes signal, signals to everyone at the gate engines cut and safe to proceed by doing a cut signal. The engines cut signal is best described as being similar to the "or else" signal you see in movies or cartoons where a hand or finger is motioned across the neck in front of the throat. haha.

Anyway, after the engines cut signal is given, an agent chocks the nose wheel at which point the marshaller will give the wheels chocked signal. 10-15 seconds is a good amount of time. Chances are, since I think we have "gate services" at BWI, the engines were kept running for a few seconds while another agent hooked up ground power. If ground power is required upon arrival, engines will not be cut until power is connected.

Quoting L-188 (Reply 3): It is amazing how many different variations of mashalling signals there are, especially when you consider it is supposed to be a standardized system.

Exactly. In my whole 6 months as a rampie, our signal to hold the brakes was a closed fist. This is the signal we use at the maintenance hangar too. If you wanted the brakes to be released, you opened your hand to show the crew your palm. I learned something new today.

Quoting Ilikeyyc (Reply 5): In my whole 6 months as a rampie, our signal to hold the brakes was a closed fist. This is the signal we use at the maintenance hangar too. If you wanted the brakes to be released, you opened your hand to show the crew your palm. I learned something new today.

Same thing where I used to work.. Closed fist hold breaks, open fist release.

We had a specialized one for the 727 combi aircraft. The Captain would hold four fingers up and we would look at the main deck cargo door and verify the four lock lights where on, and give a four signal and then a thumbs up.

It was called the "Four Locks" and verified the main deck door was secured.

Quoting Ilikeyyc (Reply 5): Exactly. In my whole 6 months as a rampie, our signal to hold the brakes was a closed fist. This is the signal we use at the maintenance hangar too. If you wanted the brakes to be released, you opened your hand to show the crew your palm. I learned something new today.

Well actually at WN, hold brakes is in fact the closed fist, and release brakes is open your hand. However, at WN, we have recently been required to use wands during the day as well. When we use wands, we hold one hand up with the wand pointing inward horizontally. Think about it. Make the fist signal with a wand in your hand...the wand naturally sticks out. It's the same thing.

i was tought a different one for "brakes on." when using wands, after crossing them into an X when you want him to stop you thake both wands and hold one above the other, parallel to the ground. a few of the pilots know it, most don't. i've been using it all the time, if i'm using wands. anybody else know of this one?

as for helos, i've recieved them using the "depart in this direction" signal from the chart when they come in from my side and i want them directly in front of me. when they're in front of me, i'll use the standard hover signal.

[Edited 2006-04-19 17:07:01]

Do these planes not have parking brakes? Surely you have already used the brakes to come to a full stop and then the pilot would automatically apply the parking brake? Why should this involve the marshaller and have anything to do with chocks? We don't release the brakes once chocks are on....or are things done differently over there?

Quoting CX flyboy (Reply 9): Do these planes not have parking brakes? Surely you have already used the brakes to come to a full stop and then the pilot would automatically apply the parking brake?

Yes these aircraft have parking brakes, but right after a landing the brakes are extremly hot, so to help cooling and prevent the brakes from sticking on the pilot will release them as soon as chocks are installed.

Quoting SkydrolBoy (Reply 10): Yes these aircraft have parking brakes, but right after a landing the brakes are extremly hot, so to help cooling and prevent the brakes from sticking on the pilot will release them as soon as chocks are installed

Thanks for the explanation. This is certainly different to the way we operate, where a well executed landing/braking does not get the brakes that hot at all....but then again we have carbon brakes fitted.

Quoting Ilikeyyc (Reply 1): Second row down, first signal on the left

Stupid me, I looked at this 10 times!!!!

Quoting Silver1SWA (Reply 7): Well actually at WN, hold brakes is in fact the closed fist, and release brakes is open your hand. However, at WN, we have recently been required to use wands during the day as well. When we use wands, we hold one hand up with the wand pointing inward horizontally. Think about it. Make the fist signal with a wand in your hand...the wand naturally sticks out. It's the same thing.

Thanks for this explanation.

Interesting to see that there IS variation in signal and procdures

BWI757

just noticed something on that picture, the "turn tail to left/right" signal. who uses that? to the turn the airplane's tail in a certain direction you have to turn the nose in the opposite direction... when would that be used? could it be for those pushbacks off of a gate where there is no tug but just a motor attached to the main wheels on the a/c?

Quoting Cancidas (Reply 13): "turn tail to left/right" signal. who uses that?

Maybe taildraggers?

Quoting Cancidas (Reply 13): just noticed something on that picture, the "turn tail to left/right" signal. who uses that? to the turn the airplane's tail in a certain direction you have to turn the nose in the opposite direction... when would that be used? could it be for those pushbacks off of a gate where there is no tug but just a motor attached to the main wheels on the a/c?

As you suggested, Pushback or backing up an a/c, turpoprops do it all the time.

WrenchBender

Quoting L-188 (Reply 3): It is amazing how many different variations of mashalling signals there are, especially when you consider it is supposed to be a standardized system.

This is true. In the past two weeks, I've been to DEN, BOS, SYR, LAX, ONT, and ORD, and because of this thread, I paid extra attention watching the different signals that were used. In general, they're standard across an airline, but there are lots of airlines at the airport, and there are some differences between them. At the "Y" in ORD, with all the different United Express carriers (TransStates, Chautauqua, Mesa, and Skywest) all lined up beside each other, it was especially apparent.

Hi guys.

Here's another hand signal that's used out there ..... at least my company used it when I worked on the ramp for a bizjet FBO at Toronto Intl (YYZ) back in the late 80's.

Certain aircraft like a Falon 20 bizjet, a Gulfstream III bizjet, a Piper Navajo, and a Convair 580 to name a few, require that the nosegear steering be disconnected before it can be towed with a towbar & tug.

So with these aircraft types, it would be normal to see ground crew pull the aircraft into postion onto a T Line and stop it there. After the "Brakes On" and "Chocks Inserted" signals have been exchanged with the pilots, the ground crew will re-attach the nosegear steering (there's different methods - some involve a large pin, some a nut & bolt, some a steel "apple" that needs to be screwed into place), and then they will signal to the pliots that their nosegear steering has been re-connected by first pointing down at the nosegear and then using a hand signal that involves holding your arms up & making a round hole with your thumb & index finger on one hand, and then inserting your other hand's index finger into the hole.

By doing the reverse with your hands and pulling your index finger out of the hole, you're telling the pilots that the steering has been disconnected.

This same signal is used to inform pilots that locking pins have been inserted into the main landing gear and nose gear struts to prevent them from collapsing while the aircraft is being towed.

When signaling to pilots that the gear locking pins have been removed (thus allowing the gear to retract after takeoff), it's normal to see ground crew personnel actually holding the pins up infront of the cockpit so the pilots can visually see that they have indeed been removed. Then the ground crew will stow them away on the aircraft.

I must mention that the hand signals used between the ground crew and pilots of jet demo teams like the Blue Angels and the Thunderbirds, etc to verify proper function of control surfaces, etc while on the ramp before taxiing off, is quite an impressive show in itself to see. They also do it very fast!  

View Large View Medium Photo © Charles Polidano

View Large View Medium Photo © Andy Vanderheyden

Chris  

Chris, I believe this is required on almost all planes with hydraulic nose gear steering. If it wasn't disconnected, and the hydraulics were switched on during the push for engine start or whatever, the steering system would try to align the nose gear with the pilot-commanded steering angle, and it would shear off the alignment pin, the towbar, or worse.

Most of the bigger types have an intercom for the pushback crew to communicate with the pilots though, so they probably don't need to rely on hand signals.

I assume this is true for pushes using a "supertug" or any tug by any other name which raises the entire nose gear off the ground. It's still going to turn the nose gear about its steering axis, so I'm pretty sure it must be disconnected from the hydraulics then, too.

Quoting Bri2k1 (Reply 18): Chris, I believe this is required on almost all planes with hydraulic nose gear steering. If it wasn't disconnected, and the hydraulics were switched on during the push for engine start or whatever, the steering system would try to align the nose gear with the pilot-commanded steering angle, and it would shear off the alignment pin, the towbar, or worse. Most of the bigger types have an intercom for the pushback crew to communicate with the pilots though, so they probably don't need to rely on hand signals.

Most of the bigger planes have a NLG steering bypass valve, which gets locked out using a pin (with hopefully a "Remove Before Flight" flag). This valve gets installed by the tow truck operator before he connects the tow bar and isolates the nose gear steering cylinders from the hydraulic supply, while at the same time connecting them to each other, so that the hydraulic fluid in them can freely move between the two cylinders while towing.

Jan

Quoting Bri2k1 (Reply 18): Chris, I believe this is required on almost all planes with hydraulic nose gear steering. If it wasn't disconnected, and the hydraulics were switched on during the push for engine start or whatever, the steering system would try to align the nose gear with the pilot-commanded steering angle, and it would shear off the alignment pin, the towbar, or worse. Most of the bigger types have an intercom for the pushback crew to communicate with the pilots though, so they probably don't need to rely on hand signals.

Quoting MD11Engineer (Reply 19): Most of the bigger planes have a NLG steering bypass valve, which gets locked out using a pin (with hopefully a "Remove Before Flight" flag). This valve gets installed by the tow truck operator before he connects the tow bar and isolates the nose gear steering cylinders from the hydraulic supply, while at the same time connecting them to each other, so that the hydraulic fluid in them can freely move between the two cylinders while towing.

Here's another example of how things are done differently at different airlines. My friends that have worked at different companies all say they used the bypass pins to push or tow aircraft. At WN, the captain will turn the A-pumps off prior to releasing the breaks for pushback. He communicates to the pushback agent via headset that "the 'A's are off". This allows free movement during pushback giving the driver full steering control. After we disconnect the towbar, as we pull away from the aircraft the captain will turn the A-pumps back on. If the nose-wheel was not left in the perfectly straight position, you will actually see the nose-wheel straighten out.

Sometimes things don't always work out properly though. I was pushing out of a gate one day that required an immediate turn. As I cranked the wheel, POP! The shear pin on the towbar snapped violently (as it is designed to do). I was like "uhhh...towbar just snapped". Captain replies saying, "hmmm...well, apparently the A-pumps didn't turn off". He couldn't get them to turn off. The rest of the push, after replacing the towbar had to go straight back.

I have also had the pumps accidentally turned on (only explanation I can think of) during the push. Haha, I was in the middle of a turn, everything seemed fine and then BAM! There went another towbar pin.

It can be dangerous if procedures are not followed correctly. If a nose-wheel was not in the straight position and the towbar was still connected (this should never be the case), if the pumps are turned on, LOOK OUT!

Yea basically what Silver1SWA said was correct. Here at BWI, once the plane has been brought to a stop, we give the hold brakes signal. We then wait for the other agent to plug the power in and put the chocks in. After the power has been turned on, we give a signal that looks like a T to the pilot. They either give a thumbs up or down if they have power. We relay the thumbs down to the agent hooking up the power so he can try to check the connection. But if all goes well, he gives me the engine cut signal, and I give him the chocks in signal and give the all clear sign for the rampers and provo.

One thing that I notice is that hand signals not only vary between airline companies, however, the vary from FBO to FBO. When I fly into an active FBO, it always amuses me the varying types of signals rampers use.


XJR

Quoting Silver1SWA (Reply 20): Here's another example of how things are done differently at different airlines. My friends that have worked at different companies all say they used the bypass pins to push or tow aircraft. At WN, the captain will turn the A-pumps off prior to releasing the breaks for pushback. He communicates to the pushback agent via headset that "the 'A's are off". This allows free movement during pushback giving the driver full steering control. After we disconnect the towbar, as we pull away from the aircraft the captain will turn the A-pumps back on. If the nose-wheel was not left in the perfectly straight position, you will actually see the nose-wheel straighten out. Sometimes things don't always work out properly though. I was pushing out of a gate one day that required an immediate turn. As I cranked the wheel, POP! The shear pin on the towbar snapped violently (as it is designed to do). I was like "uhhh...towbar just snapped". Captain replies saying, "hmmm...well, apparently the A-pumps didn't turn off". He couldn't get them to turn off. The rest of the push, after replacing the towbar had to go straight back. I have also had the pumps accidentally turned on (only explanation I can think of) during the push. Haha, I was in the middle of a turn, everything seemed fine and then BAM! There went another towbar pin. It can be dangerous if procedures are not followed correctly. If a nose-wheel was not in the straight position and the towbar was still connected (this should never be the case), if the pumps are turned on, LOOK OUT!

First, WN could still be using procedures originally written for the 737-200, which didn't have a NLG bypass valve. There the pilot had to depressurise hydraulic system A by turning off both the engine driven pump (EDP) and the A sys electrical motor driven pump (EMDP). From the 737 classic on a NLG bypass valve was installed, so that the pumps could stay on, but probably WN kept the same procedures for their whole fleet to prevent confusions.

Secondly, the EDP is permanently connected to the engine gearbox. There is no way to keep it from turning except by shutting down the related engine (or having the drive shaft shear off at a noth in case the pump jams).
To remove presssure from the EDP, you operate a switch in the cockpit, which will energise a solenoid valve in the pump, which, when opened, will short circuit the pump output line directly to the pump input, so that the pump will just move fluid in a circle, without providing pressure.
This switch and valve are normally to be off (Pump ON). If you leave it on (Pump OFF) for a longer period of time, without the pump moving fluid, the solenoid can overheat and get damaged.
I think this was the case in your example. The pilot set the A sys EDP switch to off but due to some reason, most probably a fried solenoid, the valve didn't open, so that the pump kept delivering pressure to the A system. In such a case the pilot should have returned to gate and let MX change the pump, since the shut off function is opart of the emergency functions and AFAIK not deferrable.

Jan

oh yea, forgot about tail draggers... damn airline job!!   i've only powered out an aircraft once, and that was in an alleyway between the terminal and the hangar. all i did was marshall him in a 180* turn.... we always, always push them back.