Haas suspects an unexpected complication in the 'cooking' of its carbon fibre front wing supports caused the failure that affected Romain Grosjean at the Barcelona Formula 1 test.
Grosjean had completed 13 laps on the first day of running on Monday when the front wing of his car broke off, dropping underneath the car on the start-finish straight before being destroyed.
Haas had to ship a strengthened new wing from supplier Dallara's headquarters on Tuesday so it could resume proper running on the second day of testing.
Although investigations are ongoing to find the exact reason, team boss Gene Haas said that the issue related to the failure of aluminium supports, which may have come unglued when the carbon fibre around them was cooked.
"The problem from yesterday was that the wing has a fair amount of downforce on it, so it pulled out the attachment structure on the nose," he said.
"It is some aluminium that the carbon fibre is integrated with, so when they do the process of putting the parts in an autoclave, the theory is that the aluminium heats up and then when it cools down, it pulled away a little bit from the carbon fibre.
"So it had some weakness there, and on the track with the downforce and the vibrations, that bond was not really proper, so it separated.
"The aluminium pulled out from the nose which then let the wing go underneath the car and, when he ran over it, it broke into many different pieces."
Haas said that a temporary solution was in place for the rest of this test, while Dallara ponders a permanent solution.
"They took the two little down struts where the aluminium is, they put straps around them and then put some screws perpendicular to the axis," he said.
"So now, rather than having screws that are being pulled straight down, we have screws that are perpendicular. That is the fix right now.
"We will have to come up with some other way of bonding the aluminium to the carbon fibre."