EasyJet flight loadsheet snafu caused by software 'code errors' says UK safety agency An EasyJet flight to Edinburgh Airport took off with wrongly loaded passengers and baggage because of IT network congestion causing computer systems to interact "in a manner which had neither been designed nor predicted." Last-minute aircraft changes followed by a critical but slow-running IT system meant the Airbus A321neo …
'The DCS used the aircraft registration letters as its validation for the aircraft, even though there was no cross-check linking the registration to the aircraft type.'
They should get a subscription to Flight Radar 24, they have all that information. As do the CAA. As should Easyjet considering they own the aircraft!!
You'd think that would help, one of the US carriers managed to fly the wrong A320 to Hawaii from LA. The right one had ETOPS* in large letters on the nose gear door, the wrong one didn't...
*Extended-range Twin-engine Operational Performance Standards to indicate that aircraft was fine to fly over the ocean without anywhere to divert to.
Aircraft registration letters should be unique and properly identify the instance of aircraft. There might have been a problem linking the instance to the type in some database. This may be the 'code problem' the article refers to. But the article also mentions congested IT systems. Which suggests that the database was backed up and someone's terminal delivered a (wrong version) cached copy. Or something like that.
In my days at Boeing, I worked with a shop floor document delivery dystem that was designed to 'fail active'. Rather than deliver 'something', it would post an error message* to the effect that some back end server could not be queried. So we didn't deliver the wrong paper. We delivered nothing until the problem was resolved. Some managers were not happy with this because they felt it was more important to keep the shop doing something, even if it was the wrong thing.
*The error screen included an animated GIF of a stick figure bashing his head on a PC keyboard. Just to ensure that operators not accustomed to parsing cryptic error popups would recognize that something was wrong.
"We delivered nothing until the problem was resolved. Some managers were not happy with this because they felt it was more important to keep the shop doing something, even if it was the wrong thing."
Your team had a lovely response. It sounds like some other managers figured that "quality is not my job."
I was on a flight on some largish Boeing when they asked a dozen of us to move to the front of the cabin for takeoff.
Given that we were flying out of Houston and the other passengers all appeared to be either Sumo wrestlers or going to competitive eating event - I suspect the pilot took one look and thought; fsck what the balance software says
It is, to an extent.
There was a crash of Air Midwest 5481, where the plane was overloaded and crashed in to the ground shortly after takeoff. The centre of gravity etc was pushed right back.
The NTSB worked out that the average weights used were more in line with what they were in 1936, and stated that carriers should use actual weights rather than averages. But (according to Wikipedia) 70% of the airlines in America still use averages.
I don't know if Europe uses different weights but yeah, you're not far wrong in your assumption.
> carriers should use actual weights rather than averages
I think that was specifically for these very small aeroplanes. I've been weighed on flights in the far North where you are wearing half of an REI store. It's done very discreetly so you don't see the actual number.
I don't imagine actual weight difference of 300 passengers on a 575 ton A380 makes that much difference.
Although I do think it is unfair that you get charged $1M/kg for overweight bags full of kit when Jabba the Hut's big brother is allowed to overflow into 3 seats for free.
Most planes have 3 sets of wheels having contact with the tarmac, I'm not sure if that's enough to accurate check if it is centred as all the weight tends to be within those wheels.
Edit: I know nothing about how planes are built, so high possibility I'm barking up the wrong tree!
Commented - and debunked in other comments with some back of the envelope maths. The wind would have to be strong, and hit the wings head-on, to generate any significant lift. Windage is more of an issue. But the main one is that the attitude is completely different in the air to on the ground, so wheel weights don't help.
"How come planes can't measure tire or shocks pressure to work out what they really have and how well balanced they are?"
That's a question I have asked as well. Here is how they measure the weight and calculate the balance of an aircraft. Note that, because the goal is to figure the balance when it's flying, they not only block the wind, but they also use jacks to tilt the aircraft to the angle it flies at. The procedure is a right pain so it's done only when something changes (like a repair) and then they write down the numbers for reference.
https://www.eaa.org/eaa/aircraft-building/BuilderResources/while-youre-building/building-articles/weight-and-balance/weight-and-balance
tl;dr: The balance while flying is different from weight on wheels.
In light aircraft I always calculated weight and balance with actual weights of my passengers before takeoff. It's sometimes a delicate question, but you have to look at a person and deem whether they are telling you the truth.
I did know a pilot that carried a scale with him. I never went quite that far.
This used to be the fun and games in Africa... "Do we have enough power to get all these people off the ground?" with actual weight. But back then people didn't carry 'carry-on' luggage going into the cabin weighing half a ton (I jest, kinda)... it used to be a coat, a book and (for women) a handbag.
Before the Lockerbie bombing, there were times when luggage simply had to be left behind to get planes off the runway before it ran out, and it would get loaded the next day. Inevitably that meant your luggage was not on the belt when you landed, but hey, at least you didn't run off the end into a ravine or tinder dry bush.
You are still allowed to not load luggage - although on wide bodies there is generally enough air-cargo that can be bumped first. It's expensive to leave passenger's luggage behind.
It's assumed safe because the individual terrorist doesn't know that their bag is one of the ones to fly on a different plane.
Helicopter pilots have to be very clever. Flying a helicopter is much more difficult than a fixed wing aircraft as the direction you are pointing in is not necessarily (in fact rarely) the direction of travel. Plus you have the collective to determine whether you are going 'up' or 'down'. The control column has bias settings so that you can get it to remain in a certain attitude and don't have to fight against the neutral position for ages (which can be very tiring).
I know this because I learnt to fly sailplanes / gliders as a teenager and once did some consultancy for a helicopter simulator system, which I then got to fly. It was really hard work, and I have a great admiration for helicopter pilots since. (I've also flown, under supervision, a light aircraft, which was easier than a helicopter.)
Flying a helicopter is much more difficult than a fixed wing aircraft as the direction you are pointing in is not necessarily (in fact rarely) the direction of travel.
Same for fixed wing aircraft. Track and heading rarely the same. You ought to be aware of that will all your experience. Did you ever learn nav?
The control column has bias settings so that you can get it to remain in a certain attitude and don't have to fight against the neutral position for ages (which can be very tiring).
Trim. Fixed wing aircraft also have the trim you describe. Even the most basic have elevator trim. Rudder and ailerons can also be trimmed on some types.
I found rotary and fixed wing about the same, but different in different areas. The flare at landing a fixed wing took a bit of practice, as did the roll out on a tailwheel aircraft. The hover taxi in a heli took some time to learn.
The only time I've been actually weighed was for helicopter sight seeing tour and for skydiving, both being rather small aircraft. The skydiving was tandem, and I was bolted to a instructor who could probably walk around with me bolted to his chest with minimal issue. I don't even think my feet would touch the ground.
Standard procedure in a glider, where those on-board ARE the ballast needed to put the balance point (Centre of Gravity, CG) in the right place, so everybody onboard *must* know their weight while wearing a parachute and a W&B check is done before flight.
If you're flying a single seater its up to you to know your weight with parachute, to check it against the W&B table before flying, and add additional nose weight if you're below the minimum pilot weight.
If the glider is a two seater the same applies with the weight of the person in the rear seat included only in the total pilot weight: only the weight of the bod in front is used to check whether the glider is balanced. BTW, the reason the instructor always sits in the rear seat is because that is on or close to the CG, so when a new pilot is sent solo the instructor can get out without affecting the glider's balance.
In a past life I used to fly regularly on Saab 2000s and all passengers and their hand luggage were weighed before flying. Seats weren't allocated and if there weren't many pax it was pretty normal for the cabin crew to shift us around to balance the plane. On one flight when it landed the captain came on the intercom and told us to all remain seated until the baggage and freight had been unloaded. The plane was a bit tail heavy and he was concerned that if the we got off before the baggage and freight were unloaded the nosewheel might come off the ground.
There is one airline that actually prices its tickets based on weight: Samoa Air.
But yes, the 'average passenger weight' has been upped but not by all that much. TUI probably tries to be *really* clever with average weights for men, women and kids to fly as lean as possible.
I've had it on a small flight across the Gulf of Bothnia (Finland to Estonia) where I was asked to move back 3 seats to give the little ATR taking us across on a hot day a better CoG, given that most sat either behind (closer to the exit) or around the wings. I like it up front. And I've had it on flights from H-A-H airports where people had their seats moved to help the plane get off the ground better by shifting the CoG back. The crew then allowed us to change our seats back to where we originally wanted to sit once we were in cruise.
On a 737 from Bloemfontein to Jo'burg two of us had been allocated seats "in the wrong place". The aircraft's front section had been partitioned - presumably for cargo space - and we were sitting by the crew's internal door. After take-off they moved us to spare seats at the rear of the plane. When asked why we weren't moved earlier - we were told that passengers' positions were maintained for identification in case of a take-off crash.
For that short journey the plane took off - climbed to cruising altitude - then soon descended to land. Apparently without ever diverting from a straight line. It is the only time I landed with passengers still clutching their free drinks and snack trays.
Google road journey calculator suggests you had your foot down. Bloem 247 miles (397km). Cape Town 871 miles (1402km).
The 1973 fuel crisis led to 50mph speed restrictions. A police patrol was waiting to catch motorists doing the usual few mph over the limit in a dorp en route to Cape. They were left standing when a car swept past at about 100mph.
An unlicensed teenager reckoned he had done the longer Pretoria to Cape Town run in 10 hours.
A colleague had a BMW 2002. On the motorway one day he showed me its speed - very smooth with the speedometer showing 120kmh - oops! a British imported car - mph!
What factors determined that the DCS software performed so badly with a frequently changing schedule?
I can appreciate the calculations might be complex when working out optimum balance but we’re talking hundreds of data points, not thousands, or even millions
And once a loadsheet has been created which I imagine contains passenger seating and pallet loading plan - can’t be larger than a few kb? Maybe a meg? Can it? So there should have been no issue sending this to the loaders
And despite the chaos, are we talking about a dozen flights or thousands?
Ok ok ok, I get the 5 minute window / manual entry thing, but otherwise? We’re talking a few thousand data points per plane x a few hundred planes (max) x a few kilobytes, maybe megabytes, per plane. Computationally at least, a 386 could’ve handled that
See title. Not trolling, but as a developer, recently, of load scheduling as it happens, I’m curious as to why and would like to know what I’m missing
I imagine a formal requirement.
Req: 3.141592654.... A load sheet shall be generated before boarding the aircraft
Therefore there is no mechanism for generating a new load sheet after boarding has started because that would be illegal. The formal requirements would be that in this event the flight is cancelled, a new load sheet is calculated, along with a new flight plan and a ripple effect that makes 1000s of flights delayed.
> We’re talking a few thousand data points per plane x a few hundred planes (max) x a few kilobytes, maybe megabytes, per plane. Computationally at least, a 386 could’ve handled that
You're assuming that all the data is available locally. The systems I worked with at Heathrow often took data from a data bus, but that data was sometimes only put onto the bus at 5 minute intervals (usually because it came from one particular overloaded legacy system running on ancient hardware that no one dared try and upgrade because it was so critical).
So the calculation takes only a couple of seconds but the software has to wait several minutes for all the data to be marshalled. To make matters worse, if the software just queues up changes, without checking to see if the latest change invalidates one that's already in the queue, then it could wait up to 5 mins for the first change then another 5 mins before the second happens.
At the end of the day the pilot took off anyway - so it clearly wasn't that critical.
I dunno, isn't there some sort of machine that can work these sorts of calculations out really quickly?
I am sure that some sort of device exists that can compute numbers and information, some can even provide a paper copy that is human readable.
Just musing......
I recall an internal US flight into Rhode Island IIRC (but may have been somewhere in Michigan) where the pilot stuck his head out of the cockpit door and asked, "Can some of you move nearer the back?"
Passengers had been loaded solely from the front of the aircraft and it was fairly empty.
Now, when flights are fairly empty, that's ok. However, when i have to trade in an aisle seat for something else, because i have to move, but now transformer-fold my 6ft6 frame into a cramped area, no thanks.
This mostly happens on rinkydink planes anyways.
Also, happy i'm not flying anymore. My body is very thankful for not having to endure that abuse every week...
The same thing happened back in Jan 2020 on a WhizzAir* flight from Luton to Prague.
https://www.bbc.com/news/uk-england-beds-bucks-herts-54477819
https://assets.publishing.service.gov.uk/media/5f5a0251d3bf7f7238f22fd2/Airbus_A321-231_G-WUKG_10-20.pdf
* Neither source mention the airline name but according to the CAA, G-WUKG is registered to WhizzAir in 2018. (https://siteapps.caa.co.uk/g-info/)
"The various elements of the IT system architecture do not 'talk' directly to each other but operate through a variety of interfaces"
I used to work in IT for a significant UK airline and can tell you - YES, there are LOTS of interfaces between different parts of "the system(s)" which get you to your holiday destinations.
One thing I always find interesting (in a good way) is how seriously this sort of thing is taken in safety-critical fields like aviation. There was no harm done, but an incident was raised to AAIB and fully investigated, with some actionable findings.
A lot of places - probably including mine - the most it would've resulted in is a "lesson learned" along the lines of "Oh that's an interesting failure mode of the system, we should document that in Confluence and try not to do it". It might not have even gone that far.
"how seriously this sort of thing is taken in safety-critical fields like aviation"
I love that! There's a clear focus on how to prevent problems. In some other industries, response to a problem might be "It was Little Timmy what done it. Solution: push him down a well."
In aviation, problems are not easily blamed on individuals. Okay, Little Timmy printed the wrong load sheet, but why was the wrong one even there? How did—I don't know—Dispatch have different aircraft data than Crew? How could we have prevented the problem and how can we catch it better next time?
I did, but I still don't understand!
The 'wind excuse' is debunked as explained, and knowing the stress on all wheels I don't see why it would be impossible to calculate the position of the center of mass. It would be anyway much more precise than the estimation made by companies with outdated statistics.
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