Balance Problems After Pushback???
 

Yesterday we dealt with a 2.5 hour delay on UA 909 (ORD-DEN) because the morons on the ground did not load the plane properly.

This happens more than it should...I've been on many flights where we're at the end of the runway but have to pull out of sequence to adjust weight and balance issues. And that's exactly what we did yesterday.

Shouldn't this no longer be a concern at the time the cargo door is shut? Why does the plane even push back if there is a warning light on in the cockpit?

We were told yesterday that the reason for the "mess up" was that somebody miscalculated the kilos vs. pounds. Probably not a good thing to announce to the plane. Fortunately, Boeing's technology detected this idiocy.

Incidentally, the crew was HORRIBLE during this delay. Didn't even bring back water or offer any kind of refreshment to F and C...they just stood in the forward galley chatting among themselves.

Happening to me a lot lately too...

In one case we were at the end of the runway, ready to rev up the engines and were recalled to the gate.

Last Friday on IAD-SEA we sat 20 mins by the end of the runway just waiting for them to run the numbers! We got out the gate on time only for the person with the calculator to hold us up.

I was recalling all my delays for the past year on UA and determined that ALL of them were due to human error. Yup, Ive had no mechanicals or weather issues believe it or not!

I'd rather be delayed due to W&B than take off, stall, roll and nose-dive into the ground.

Just be glad they caught the error IMHO. ;)

Of course, the "morons on the ground" seem to be causing me problems lately too. :D

I'm still trying to figure out why LGA always seems to be "surprised" when our plane arrives and we ending up sitting around on the taxiway since we can't pull up to a gate.

Amen to that -- W&B is definitely something you don't want to mess around with, as that US Exp. accident at CLT shows. I've often wondered, like the OP, why they don't resolve this before pushback. At an airport like ORD there's enough time in the taxi for central dispatch to finalize the W&B calculations, but that's not true at all airports. I was on a flight from AMS that was delayed by about 45 min. in the penalty box because the computers went down at central dispatch. Given traffic at the time (thanks Ch. 9) it would have taken no more than 5 min. to taxi out and take off. So it does seem strange to push and then do the numbers, rather than stay at the gate where any discrepancies can be resolved easily.

This is the part I find inexcusable. Final W&B numbers are run after pushback, IIRC, and sent to the flight deck from dispatch via ACARS. I can see a last minute shipment of cargo or extra bags from misconnects throwing the plane over its zero fuel weight or out of balance and would much rather have safety take precedence. But a 2.5 hour delay with no cabin service is utterly incomprehensible and completely inexcusable given the new and stupid TSA rules, even in Y. You should definitely complain about this -- loudly and clearly -- and demand compensation not only for the lack of cabin service, but for the arrival delay. Making them pay is the only way these sorts of things will be fixed by management. This is not acceptable by any stretch of the imagination.

What is the technical reason for running the numbers remotely? What kind of computer does "central dispatch" have that woudln't fit into an airplane (on a single, little chip)? What's the data -- the number of bags? That makes no sense to me, so clearly I'm missing something.

Weight and balance is not a warning light, but a calculation that the captain gets to determine fuel requirements, etc. and to go ahead with takeoff. These numbers are calculated in a central location at the field and transmitted to the captain. It's often the case that they push back with the expectation that the W&B numbers will come through ok before engine run-up.

At least this is my understanding. I'm probably off on the details, but I think this is the gist.

Wirelessly posted (BlackBerry8700/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/100)

W&B must also be done by a Flight Dispatcher, which is an FAA licensed individual and not just a guy with a calculator. I suspect it is more economical to have them all at WHQ rather than dispersed to all the stations.

Also, W&B calculations also determine things like rotation speed, takeoff speed, flap settings, etc, that are affected by the weight of the airplane. (And pretty important to the safety of the flight).

Still, no reason why a flight should be delayed for this.

There is no particular technical reason for doing this remotely other than central dispatch can do the job more accurately using more powerful computers. Fuel loads, passenger loads and cargo loads are all sent into the UAL computer system and accessible by dispatch more easily than by the crew. Private jet pilots do all this work themselves and, in the era before high speed computers, so did airline pilots.

The data involved is weight, and where it is located on the airplane. There are several numbers that are critical: Ramp weight, take-off weight, zero fuel weight and the balance of the airplane, expressed for large aircraft as % of mean aerodynamic chord (%MAC). A properly loaded aircraft at a given weight must fall within an acceptable envelope of %MAC to fly and %MAC is a function of where weight is distributed on the aircraft. A plane may be within acceptable weight limits, but out of balance because a heavy piece of cargo is in the forward cargo pit as opposed to the rear, or vice versa. The combination of final weight, outside air temperature, pressure altitude and %MAC then determines various performance variables for the takeoff such as the various V speeds, runway length requirements and trim settings. All of these calculations are done from numbers sent by computer to the central dispatch facility at Chicago, where dispatchers crunch the numbers and send the data to the flight deck by ACARS (Aircraft Communication And Reporting System), a kind of inflight e-mail system. While preliminary numbers are given to the crew in the dispatch release, the final numbers are sent to the plane after pushback and the aircraft is reconfigured as necessary using those final numbers. On this particular flight, something happened between the preliminary numbers and the final numbers that caused dispatch to raise a red flag.

I have to admit that I'm a bit perplexed as to how there could be a 2.5 hour delay in this case. If I were to hazard a guess, it would be that the aircraft was overloaded. Perhaps the delay was due to problems getting a ramp crew to offload some of the excess weight. As any pilot will tell you, weight and balance is a crucial safety issue and it's not something you want them to get wrong. That part I would have patience with. F/As standing around gossiping for the duration without providing any cabin service I have no patience with whatsoever.

Weight and balance isn't done by a dispatcher, although some data that feeds into it are calculated by dispatcher. It is VERY rare when the actual final weights need to be changed for takeoff. In reality, if they are close to max take off gross, this should be detected far beofre pushback. The numbers you are waiting for help set the trim settings for takeoff. If the numbers are off so much that they fall out of the adjustable trim settings, then you will end up with a trip back to the gate. This is VERY rare. THE MTOG and basic planning (estimated passengers/fuel/OEW/baggage/cargo, as well as taxi fuel should be prerun based on planned load, route of aircraft...etc. The small variances that occur are adjusted for by changing the trim sttings, but as has been noted, one can exceed this, and can exceed th MTOG as well.

Local conditions dictate much of the planning and can change. For example, one may plan on taking off from runway XXX with 9000 feet, then a shift in wind may force you to use a different shorter runway.

I recall a flight back in the day ORDGRU. Turned out one of the alternate airports in South America (emergency landing spot) was closed by the local authorities. Dispatchers had to plan an enitre new flight plan, increasing the distance, requiring more fuel. This was a 767 which was already at max range for the fuel/weight. Plane had to return to the gate, volunteers were taken, cargo was offloaded, and fuel was added. During the 90 min this took, ORD had closed the runway they were planned on using (there was overnight construction, and this delay wasn't communicated to the airport authorities.) This was going to cause anonther HUGE delay as well as requiring even more weight to be dropped (to the point that the flight was almost pointless to operate...nothing onboard <slight exaggeration.>)

Well, in this case the dispatcher really came thru. Thru whatever channels they have, the South American airport was "reopened" and the original flight plan was reinstated, although I believe the volunteers and cargo were not brought back, as that would have delayed another 90 min.

The other thing...this is a mechanical delay, meaning UA can be held liable for providing compensation. Having a "calming" crew can significantly reduce the number of p*ssed off passengers.

A year ago, I was departing SYD, seated in Y+, when we sat on the tarmac after pushback for like thirty minutes. Then the purser came running back to my seat and asked my name. I told him, and he asked me to come forward because they had a better seat for me. This happened to about 6 people, and we all got business class seats. The purser stated it was a W&B issue.

So I guess there is a positive to some problems...

With United's system that places blame when a flight departs late, I have seen pilots push back before completing paperwork in order to have an one time departure. They hope that they will have it done before they get to the runway. That way if they push back on time, but have a long queue it becomes an air traffic delay, not a crew delay. I have also sat on the side of a runway for over 20 minutes after being told we were #2 for departure but that the paperwork wasn't done so we were going to have to pull out of the queue. On that flight, we boarded 20 minutes late because the Pilot didn't show up at the gate on time (and came waltzing up 18 minutes after boarding was supposed to start with a duty free bag). They rushed us on to the plane, shut the door two minutes late and then we got to sit on the tarmac.

Once upon a time, W&B was calculated locally at the airport. At the smaller stations I would guess the crew did it themselves; at larger stations there was a small group of employees dedicated to load planning. My understanding is that it has all been centralized at WHQ as a cost-saving move (don't have to pay the load planners at the airports anymore). Extra computer power isn't an excuse; they could be accessed remotely if that was the only issue.