I'm not familiar with this aircraft but it is being reported that the EGT / TGT gauge was the reason why the aircraft returned to the gate. I know that this is a no-go item for the majority of aircraft and I find it hard to believe that it would be allowed for the MD82.
If this is true and the crew departed with the gauge in-op this would be a serious error of judgement. Madrid is alot hotter and higher than most airports in Europe. The monitoring of gas temperatures is critical at any airport but to a greater degree at Airfields such as Madrid. I hope this is not the case.