What caused the LaGuardia plane to go off the runway?

NEW YORK (WABC) -- We heard how just prior to Flight 1086 landed; two planes had reported no problems braking. But a careful examination of the air traffic control tapes reveal some problems and we've also learned through those tapes that de-icing chemicals were not being used even though temperatures had dipped below freezing.

The damaged aircraft is now tucked away in a hangar where NTSB investigators will examine every inch. From tires and brakes, to the broken nose and wing, all providing potential clues as to why Flight 1086 skidded off LaGuardia's Runway 13 on Thursday. Equally as important, will be interviews with the pilots.

"They will be wanting to find out exactly what calculations the pilots made based on the wind conditions in determining exactly how they were going to land the aircraft," said James Hall, former NTSB chair.

Investigators will also scrutinize the condition of Runway 13. An Eyewitness News search through Air Traffic Control tapes reveals mixed reports from pilots.

"Braking action is good United 694," the pilot said.

But just a couple of minutes before that another pilot reported problems braking.

"Braking action at medium at touchdown and getting worse than that down here at roll out," the pilot said.

"Say again?" the tower said.

"Braking action is poor down here at Mike," the pilot said.

He's referring to poor conditions at taxiway Mike which is near where Flight 1086's long skid ended. Also, about 20 minutes prior to the accident, with snow picking up and temperatures falling, operations gives Air Traffic Control this update on the runways.

"We're advertising in NOTAM a quarter-inch of wet snow. The runways have not been treated just grooming and plowing," operations said.

What's clear is that despite it being 6 degrees below freezing, Runway 13 was not being chemically treated for icing conditions, even though much of it is bordered by water. A former pilot who spent decades flying for Delta explains how he would have felt had he been in the cockpit landing at LaGuardia Thursday.

"Uncomfortable, yep. Anytime you have a tailwind on runway with slightest bit of contamination especially LaGuardia's 7,000 foot, not a lot for jet, and with a tailwind component it is very uncomfortable," said Robert Ober, a retired pilot.

The Port Authority says the ground crews decided against putting chemicals down because they would have been swept wiped away.

A spokesman adding that they were having success with their brooming and blowing operations.

The question is would continued de-icing treatment have helped.

That will be up to the NTSB to determine as they examine any mechanical or human factors in this accident.