GIGO Almost Caused Plane to Crash
A very interesting story: GIGO Almost Caused Plane to Crash "Instead of entering the true weight of 362 tonnes on the laptop, the aircraft weight actually entered was 262 tonnes. " The airline now has a second laptop for data entry.
But I wonder if a better approach would've been a reasonableness check. That is factor in the empty weight of the aircraft. Add the weight of the fuel which has to be entered somewhere somehow. Then enter the number of crew and passengers and guesstimate the weight per person. Which airlines already do. Also enter in the weight of the freight. Then compare that rough computation to the weight calculated by the airline dispatch which is entered. If it's accurate with 5% or 10% then great.
|Empty weight is 170,400 kg ||170 tonnes|
|80% of Max fuel 214,810 L at 0.8075 kg/L ||139 tonnes|
|275 Passengers with luggage @ 100 kg ||28 tonnes|
| Rough guesstimated total ||337 tonnes|
|Entered weight which was in error ||262 tonnes|
Information sources - Wiki - A340-500, Wiki - Jet Fuel
The guesstimated weight is 30% over the entered so a severe reasonableness problem. Unless I've screwed up a computation especially the weight of the fuel. I chose to use 80% of the maximum allowed fuel as this was a long range flight. But even 50% of the fuel would've failed a reasonableness check.
I also had no idea how much fuel is on a typical long range jet. No wonder the landing was hard as they were unable to dump enough fuel.
Finally I'm glad for the sake of the lives of the crew and passengers that there was a control called "TOGA on the thrust levers" which allowed the flight crew to get maximum power.
Every few years I read of a similar problem in the stock market. A clerk enters either a stock quantity or price which has an extra decimal place or two in it. And it costs the clerk's employer millions to unwind the stock trade.
Your esteemed blogger once did the same 25 years ago. The client, a major Canadian heating, ventilating and air conditioning wholesaler, wanted to send customer data to Dun and Bradstreet including the customers annual sales as well as current, 30, 60, 90 and 120 days overdue amounts. I happily setup the 1200 bpi reel tape files with all the appropriate data. The accountant then calls me in a week or two later and tells me that I included the amounts with the cents when I should've included just the dollar amounts. So a given customer showed $10,000,000 in annual sales rather than $100,000. And $200,000 in 30 days outstanding rather than $2,000.
I was told that Dun and Bradstreet never noticed for a week or so and then had to labouriously back out my clients specific numbers from the data.