I wrote:
Let me add that after that accident some woolen threads were installed at the roots of the wings of the MD80, free to shake into the wind, in order to facilitate the identification of subtle icing Vetrone by the crew, often unnoticed.
Mostly correct but they were not put there to depend on the wind for visualization. They required movement by a pole device held by a man on a ladder. If you couldn't move them they were probably covered by a film of ice.
I am grateful for correcting me.
As a matter of fact I remember that we were expected to perform a visual inspection of the tuft on the upper surface of the wings from the cabin, in case of doubt we had to open the wing emergency exit, go out and touch the surface to ensure that there was no ice.
The biggest problem with the dispatch with wing ice was the first flight of the day after an overnight in drizzle/snow. The snow would be blown off on the ground but they missed the check underneath for ice
As we all know there’s a phenomenon called cold-soaked fuel, which happens if the aircraft is parked with wing tanks not completely filled with fuel, which then evaporates. This gas expansion reduces the temperature, and so even if the outside air temperature does not fall below zero, the moisture in the air condenses and then freezes in contact with the sheet of the wing. During the walk around a 3 mm layer of frost was acceptable below the wing corresponding with the tanks.
It seems that those ice formations, resulting from the cold soaked fuel, broke during take off, causing both engine flame out which determined the crash of the MD-81 SAS in Gottrora on December 27, 1991.
Contrary to popular belief there were only a few incidents of ice due to cold soaked fuel in above freezing conditions.
So why, before their production was discontinued, a plan has been made to install de-icing panels at the root of the wings of MD 90/Boeing MD 717?
AirRabbit:
It's really moving the ardor with which you defend the actions of the crew of Air Florida Flight 90 which crashed into the Potomac January 13, 1982.
Many wise philosophers in ancient Greece argued that we should defend a friend by all means also we know he's guilty.
Nevertheless you will agree with me that the following illegalities were committed:
- They did not insert Engine Anti-ice after start, and did perform the periodic engine run up.
- They tried invain to push back (the tug connected) through the use of reverse (thus raising clouds of snow and slush).
- They knew they had snow on the wings, so that they approached the preceding DC9, in the vain hope that their jet engines would swept it away.
- They started the take off run 50 minutes after the de-icing.
- They accepted a very little separation with the landing traffic despite the poor visibility and the snow storm. (If they had to abort the takeoff? If the others were to go around?)
- They underestimated the irregularity of the engines parameters for takeoff
- They had found that the acceleration was so poor that they had reached 120 knots after 45 seconds.
- They began to rotate as per “the soft field” (I began to hear such an expression only since I'm instructing in general aviation) and then starting the rotation well before Vr.
I'm sorry but I have to tell you that History has been written.
So much time and money has been spent to establish the causes of the disaster, so justice was done and the incident would had never happened again (sic!).
So unless you have any new evidence to reopen the trial, agree with NTSB.
Let’s shout together:
“How can you know if any kind of snow is ‘ADHERING’ to the surfaces of your airplane, and no ice is beneath it, if you don’t remove it?”
“No clean aircraft? No Fly!”
Here you are Lomapaseo.
Is this the way you like it?