Monday, 24 November 2008

Heavy Play

Following on from my last post, Aviatrix has published two interesting posts about weight and balance on Cockpit Conversation . Have a look at those if you want to know a bit more.

In my company, we do get wide body aircraft on a regular basis during the peak season. During the off-peak season we're in now, they are few and far between but we still get the odd ad-hoc charter passing through our hands. I had the luck of the draw recently for an A330 passing through us, destined for shores more exotic than my own.

The flight was a split-load with another airport, and positioned into us with passengers and cargo already on board going to the same destination. They remain on board the aircraft as my passengers join them and we load the holds with more bags and top up the fuel.

The basics of loading a wide body are much the same as the smaller aircraft I discussed in my last post, in trying to balance the weight to get an ideal trim. But sometimes with wide body aircraft it can get a bit more complicated. On this particular A330, there are belly holds at the front and rear of the aircraft. Some versions of it also make use of the area between the wings.

The flight is bin loaded, meaning that all the suitcases are in aluminium containers called Unit Load Devices (ULDs). They come in various shapes and sizes to fit aircraft holds. For example, on A330s we can use AKE and ALF type bins, but on 767s we have to use DPE and DQF bits. The dimensions and shapes are different to allow them to fit snugly in the hold of each aircraft without wasting space.

We're using AKEs and ALFs to load this flight. ALFs are large containers that span across the belly hold from left to right, where as AKEs are half the size and you can fit two side by side in the aircraft. We load and count the bags into these bins, and then work out the gross weight of each.

I have a plan view of the aircraft's holds, depicting the different locations we can load the ULDs or cargo pallets. The diagram is marked with squares labelled 11L, 11R, 12L 12R, 13R etC. The first number is the hold number, and the second number is the row number for the ULD, followed by L or R for which side of the aircraft. Eg 13R is Hold 1, row 3, on the right side of the aircraft. We can fit 1 AKE in this position, or 1 ALF positioned across 13L and 13R. Cargo pallets are bigger yet again than ALFs and have their own divisions that span across the hold and over 2 rows. Their divisions are labelled 11P, 12P etc.

The aircraft arrives at my airport carrying carrying bins and cargo pallets from it's first departure airport. The handling company there has placed all their cargo and ULDs in the rear holds, and taken up all the available positions leaving me only the front hold to place my outbound ULDs. The ramp guys have managed to fit all our bags into 3 AKEs and 1 ALF, and I also need to load some empty AKEs that are to travel to the destination at the request of the airline's ULD Stock Control people.

A quick count reveals there are 14 AKE positions in the front holds, or can be used as 3 pallet positions and 2 AKE positions. The rear hold has room for 2 pallets or 6 AKEs. I plan to put the ALF at the rear of the front hold, nearest the wings, with the loaded AKEs in front of this, followed by the empty AKEs. Today it's easy enough, but on the return flight with the split load it could get more difficult. Generally if an aircraft has two destinations, the handling company at the departure airport will load it so the first destination cargo and bags can be offloaded without moving the remaining the cargo for destination 2. Sometimes, it's not always possible though as it results in the aircraft being too tail heavy, so we would need to remove ULDs and pallets to get access to our ULDs, and then reload the bins and pallets for the next destination.

On the other hand, if we are able to remove our ULDs without moving anything else, the result might be the aircraft is out of trim now and so we need to move the remaining weight anyway. It's good practice to try and plan it so it works out easily for the ramp guys the other end. For you can be sure if we make it difficult for them, they can end up doing the same for us when the aircraft returns! With so much to consider, it's easy to get caught up in the loading of the aircraft alone and forget about the other things that need done.

Upstairs, the first of 186 passengers are already boarding and taking their seats for a long 9 1/2 hour flight ahead of them. I'm used to working with smaller aircraft so much that it still surprises me a little when I step on board and notice the size of them inside and galleys big enough to put restaurant kitchens to shame.

Fuelling is taking place, the crew have requested 68,000kg of jet fuel. That's a lot, and still makes me go 'Whoaa' when I think about it. A fuel truck is parked under the wing pumping fuel in, and another truck is waiting behind it. I can see the drivers are bored sitting watching the gauge tick over, gallon after gallon. It takes a long time to uplift 68,000kg of fuel.

Once the positions of each bin is decided, loading is speedy and finished well ahead of the scheduled time of departure. It's a good day, all my passengers turn up and board on time too so all I have to do is wait for fuelling to finish before we can go.

Fuelling finally finishes and paperwork complete, I say goodbye to the crew and let them close up. I do my walk around feeling like a little kid in a big playground. I'm looking for anything unusual like I discussed in my Walk Around post, but I'm also in awe of the size of the aircraft. The main deck sits well higher than any other aircraft I deal with, the wing span is massive and I can see the wings drooping under the weight of the fuel. We begin the push back and the tug struggles a little at first. Pushing 204,000kg of aircraft takes a bit of grunt, especially on the slight incline we have. The engines start up and I get a nice whiff of jet fuel as I hear that resonant hum.

Push complete, we disconnect the equipment and I wish the crew a good journey. I have to walk a few miles away before I can even make eye contact with them and show them the pin because they're sitting so high they're almost in orbit.

A few minutes later, I hear the engines spool up and it starts to accelerate down the runway. The engines make a fantastic snarling sound of a roar that makes the hairs on your neck stand up. It speeds past me, I see the wings load up and a few seconds later the nose lift gently off the runway. The main gear lifts off and assumes its usual angled position before being raised, and off into the cloud it climbs gracefully...

Sunday, 23 November 2008

Standard Loading

I had started to write a post about a recent wide body jet I had to deal with in work and about the loading of cargo and bags on it, then realised I better start with an explanation into loading of smaller aircraft.

So you've all seen the ramp guys chucking/throwing/pass the parcel-ing/delicately placing the suitcases into the belly of the aircraft, but have you ever considered it in anymore thought than that? Unless your an aircraft buff/engineer/physicist etc then I hope not but here's a short explanation into what happens.

For example, one of our flights with an A320, with 180 people onboard and nearly all of them having suitcases checked in will result in around 180 bags. At an average of 15kg per bag, those 180 bags amount to 2700kg. That means we have 2700kg of bags to place in the belly holds and that need to be distributed so that the aircraft not only remains in balance, but go one step further and make sure it's distributed to give an aft Centre of Gravity and help reduce fuel burn. Most of the flights I deal with are all lose loaded, the bags are loaded on individually and aren't contained in the big metal bins or Unit Load Devices (ULDs) you'll see on some of the larger aircraft.

On the A320s I work with, there are holds both fore and aft of the wings. The front hold is numbered 1, there is no number 2 hold for reasons beyond me, and then hold 3 and 4 are located aft of the wing. There is also a smaller hold 5 at the tail of the aircraft which we rarely (have to) use. The aircraft in question, without passengers and bags is pretty well balanced, not too nose heavy or tail heavy, so the obvious answer would be to split the bags between the front and back equally. Almost, but that's pretty much what we do.

The standard way we load a full A320 is by putting 1/3 of the bags in H1, 1/3 in H3 and the other 1/3 in H4. So 60 bags each in 1, 3 and 4 resulting in 900kg in each hold. This holds true for when the aircraft isn't full as well, with lighter passenger loads we can still split the bags up into 1/3s among the holds providing the passengers are distributed equally throughout the cabin. 99 times out of 100, this method works fine and if we're feeling adventurous and have the time, we'll co-ordinate with the flight crew to try and refine it to an even more suitable arrangement producing a more ideal CoG.

A321s I don't have a lot of experience with and so I can't tell you off hand the way we usually load them, but we do have to be a bit more careful. The longer fuselage means any weight in H4 or H5 has more of an effect in making the aircraft tail heavy. If you're not careful enough and place too much weight in H3/H4 without any in H2, you'll very quickly find the tail making it's way to the ground and have endless paperwork to fill in as the flight crew berate you, to put it lightly.

For 737s, it varies depending on which series. On the older -300s and -400s, we're generally load around 100-120 bags in H3 and anymore in the front in H2. On the larger -800s, we'll usually fit around 140 bags in hold 3 aft of the wings, and the remaining 30-40 in the forward holds.

For 757s, the numbers are bigger yet again with around 180 bags in the rear split between holds 3 and 4, and then the rest in H2.

Some particular aircraft have their specific quirks about them. For example some aircraft are particularly nose heavy or tail heavy due to modifications, such as those that operate dual role and have a cargo door in the side of the fuselage. We'll always load and unload the aircraft in such a way as to minimise the possibility of it tipping while on the ground, meaning we'll generally load weight in the front first, and start offloading the weight from the rear on arrival. I've had captains call me overly cautious about my order of loading. However, that's easy for them to say, they won't be the one taking responsibility for it if it ends up nose up while sitting on stand.

Anything bigger than these such as 767s, A300s and A330s are in my experience all bin loaded and so get a bit more complicated. At least now the next time you see the ramp guys place some bags in a hold and then moving to the back/front hold before the other is full, you'll have an idea why. Now I can get on with finishing my wide body post...

Wednesday, 12 November 2008

The race is on

Another quiet week in work, and many more destined to come by the looks of it until nearer Christmas. If you have any specific questions or queries, ask and I'll have a go at answering them as best I can in case I run out of blog ideas.

One of my flights this week was a short domestic 30 minute turnaround, lots of fun to do when things are going well and generally hassle free. Passenger numbers are usually around 60-80 with maybe only 30-40 pieces of hold luggage so everything can be loaded and unloaded quickly.

I head out to the aircraft parking stand a few minutes before it's due to arrive. I check everything is ready, steps are standing by, tug, chox, a ground power unit, and the outbound bags. As I nosey across the ramp I see an old friend on the stand beside me.

I have known this guy for longer than I have worked at the airport. Both of us from very different backgrounds and a friend of many years. When we first met it was through another line of work, and here we are a few years down the line both working in dispatch at the same airport, albeit it for different companies. I have a quick chat with him and catch up, and find out that he is dispatching a flight on the adjacent stand to me in 25 minutes. His is due out at 1700, mine at 1705, but mine is due in slightly early and ahead of his. The race is on!

1632 - My aircraft arrives on stand, 3minutes early. The engines spool down and the ramp guys spring into the action. As soon as the steps are on, the doors are open and the passengers start getting off and head towards the terminal.

1635 -About half way through de-boarding, my friends aircraft taxis in on the stand beside. This means I have to stop our passengers disembarking until the other aircraft comes to a stop and the engines have spooled down as it's parking on the same side of my aircraft. The Fuller arrives at my aircraft and starts pumping, he should only take a few minutes.

1648 - My outbound passengers start boarding. I have already given the crew all the necessary paperwork, the outbound bags are on board, fuelling is already complete and all I need now is for 67 passengers and 3 infants to be on board a.s.ap and I can get the aircraft away again. I stand on the ramp under the wing, making sure passengers don't walk under it and complete my own paper work. I glance across towards my friend's aircraft and see him standing grinning at me. He is already boarding his passengers too. The airline he is working with runs a 'tighter ship' with turnaround times.

1656 - Boarding is complete, it's one of those good days where all the passengers turn up and board, no running around looking for the last two or three who are still sampling the terminal bars. I inform the crew, collect my signed paperwork and close up. The ramp guys pull the steps away as I spring off the bottom of them.

1658 - Walk around complete, equipment clear, I don my headset and eagerly await to get going to beat my comrade. To my right I see him and his aircraft closed up and also ready to go. Unfortunately it's now down to whichever flight deck crew request clearance from ATC first.

1658 - Doh! The beacon on the other aircraft starts flashing top and bottom of the fuselage, and I see my friend give the hand signal to his tug driver to push back. He's got in ahead of us, and we won't be able to push back now until his aircraft has taxied off. Frustrating, but my flight is still on time.

My friend gives a smug smile across the ramp and a wave, I'll get him back someday :-) It's time to return to the office for another few hours of poignant discussion about inane subjects and browse youtube. It's a stress free day again.

Friday, 7 November 2008

Spare a thought...

So we all knew summer wouldn't last forever and the cold would return, but that doesn't make it any easier.

The frost is back, the de-icing trucks are being used again and everyone is walking about the ramp looking like they are smoking as the breath escapes their mouth. It's bitterly cold, but I like it, almost.

The cold brings with it a crisp clearness that gives great visibility. From the ramp I can see out for miles towards hills and mountains I haven't seen all summer with the hazy air and cloudy skies. Where I am we see more of the sun in winter with the cloudless blue skies on frosty days, than in summer. Wearing sunglasses for driving is a fashion statement in summer, but a necessity for winter here.

So as I stumble about the ramp with multiple layers on, looking remarkably like a Michelin man figurine wearing a high visibility vest, I'm in a slight mood of awe. Contrails criss-cross the skies above me, I can see the aircraft lined up for miles one after the other on approach, and friendly crews look down from the flight deck at me and grin as they watch me stand involuntarily shaking in the cold. With the light passenger loads at the end of the season, aircraft are far from full. Couple these low take-off weights and the cold air jet engines love, they blast off the runway and climb towards the sky like rockets.

I'd much rather have the frosty cold days with blue skies and no wind than any rainy wet day with gales blowing. The bitter cold makes me slightly uncomfortable, but wind and rain make my job painful and messy. Try completing paperwork as the rain lashes down turning it into paper maché, and any dry bits remaining have a strong desire to go flying on their own across the ramp in the wind. I take pride in my appearance, but there's no way to look diginfied walking into a flight deck to talk to the crew with water dripping from your face or your hair pointing skyward, and handing them a piece of paper that once was a load sheet but now vaguely resembles a box of tissues that have been plucked from a puddle.

So as you step outside on your way to work in the cold these mornings, spare a thought for those of us who have to work it, and and I'll think of those even more unfortunate than me who are stuck in it all day or work somewhere colder than my airport. Still, I love my job...most of the time.

Wednesday, 5 November 2008

The secret conversation

I apologise for the silence over the past two weeks but I've been kept busy, not with work, but other things. Hopefully I'll get a bit more writing accomplished over the next few weeks. Continuing on from my last post about walk around checks, this one will give you a little insight into what the guy wearing the bright luminous headset is doing during push backs.

So with my walk around checks complete I'll plug-in the headset so I can communicate with the crew. If it's familiar type like the A320 or 737s, I know where to find the plug. If it's something I'm not used to working with such as an ATR, I'll stumble about around the nose and gear looking for some sort of plug to connect the headset to because I forgot to ask the crew where it is when talking to them.

Once I'm plugged in, depending on the aircraft, I'll either give the Push to Talk (PTT) switch on the headset a click to let the crew know I am now ready when they are, or stand in their line of sight awaiting their call. For 737s, I can easily stand within the headset cable's extension and the first office or captains line of sight, as they sit much lower than the A320s. For the Airbii, I'll give a a quick mike click, as to see the flight crew I would need to move a considerable distance out from the aircraft stretching my precious cable. It extends to something like 12m when stretched but I never pull it this far as I don't fancy trying to recoil and carry 12m of cable away once finished.

Some aircraft have a Pilot or Flight deck call switch located next to the port for my headset, though I've never used it it. I figure the last thing they want is another ding or dong going off in the cockpit as they make the final preparation before push back.

Speaking of thee Pilot call buttons, I was almost caught out once with a 767. On the 767s I have worked with, the headset plug is located on the back of the nose gear together with some other buttons. Beside the headset plug is a LARGE RED button, and most, including myself would assume it is the flight deck call switch. Assume nothing. Experience has taught me flight deck call switches are located next to the headset plug, but equally experience has taught me not to push large red buttons unless I'm certain I know what they do. The red button is in fact an APU fire extinguish button. Press it and I'm sure you will get the attention of the flight deck, but more a long the lines of chronic swearing as they wonder why the APU has just died and the fire bottle discharged.

When the crew are ready, the First Office or Captain will speak to me on the headset, depending on company procedure, generally starting with,

"Cockpit/flight deck to ground, helloooo?''

I'll respond with a hello with more o's than his. Again, dependent on the airline procedure or the captain in question, he may well ask for my checks to which I reply that all the aircraft doors and hatches are secure, ramp workers and equipment is out of the way, the chox are removed from the wheels, and the steering by-pass pin and tug are all in place.

By this stage, he may already have his clearance from Air Traffic Control or ramp control, to push back. If so, he'll tell me they're cleared for push and start, together with which runway they'll be departing from. It's important I know which runway or taxiway he'll be taking after the push back, so as I leave him pointing in the right direction. So providing both parties are ready and clearance is received, I'll ask him to release the parking brake and wait until he replies with a unambiguous 'Parking brake released, cleared to push' message or words to that effect.

Ground to Flight deck?
Go Ahead
We're ready for push back, release parking brake please.
Parking brake released, cleared to push for runway 30/taxiway Golf etc.. let us know when we can start engines
Ok pushing back, standby for start.

The aircraft is now 'in my control' through the tug. I signal to the tug driver the parking is off and we can push back, and through a series of further embarrassing hand gestures making me look like an 1980's dancer, tell him what direction to leave the aircraft facing.

So as we start moving back, I'll be on one side of the aircraft watching the wingtip making sure we don't hit anything, and a colleague will be on the other side doing the same. When it's safe to do so, I'll inform the flight deck they are clear to start engines and they'll let me know the sequence they are starting, such as no.2 first followed by no.1

Clear to start number 2 and 1 as you wish
Starting engine 2 then 1

As the engines start up, I'll observe them to make sure nothing out of the ordinary happens such as black smoke, or foreign objects being sucked into engine or fire. I believe there are still some airlines who require the person on the headset to be an engineer for the push back, but none that I deal with.

When we have finished pushing the aircraft and come to a stop, the tug driver will signal to me that he has set the brakes. I'll call the flight deck and ask them to set the aircraft parking brake again. Once I'm told it's set, we'll start disconnecting the tug, towbar and remove the pin from the nose gear. If all the engines have been started and everything appears normal by this stage, the crew will inform me I can disconnect, revert to hand signals and show them the pin.

I'll reply and tell them what side to look for us on for the hand signals, wish them well and disconnect myself from the aircraft. I'll then walk with my colleague to one side of the aircraft, my friend will hold up the steering pin he has removed, that has a large red flag attached. It tells the crew they now have steering control back, and I'll give a thumbs up signal followed by a wave letting them know we're all clear from the aircraft.

Ground to flight?
Go ahead...
Push complete, set parking brake please
Parking brake set, 2 good starts, clear to disconnect and revert to hand signals, thank you
Ok watch for the pin on the left, good morning

I told you it wasn't exciting, but maybe the next time you're sitting at the gate and your companion asks what the guy on the headset is doing you'll be able tell them. However that's just in my part of the world and how we work, I'd be interested in what it's like elsewhere. Any input from crews on their experiences with ground crew and push procedures would be interesting.