NWA Flt 6231 was drilled into us. As I understand it. that was a time when there were no lights to indicate that the probe heat was on (or something like that). 90% of that problem is recognizing it- pitot tube blockage due to icing. If you are flying in a steady state and your airspeed goes fast for no apparent reason, don't be so quick to pull the power. Fly known power settings and attitudes.
https://en.wikipedia.org/wiki/Northwest_Airlines_Flight_6231
My understanding is that the NWA-Delta merger was the best merger ever! Seriously. Both airlines were about the same financial strength for different reasons, both had gone through bankruptcies, so the typical friction between pilot groups, not gone, but lessened significantly. I did lose about a year of seniority, but it made no difference to me because I continued to fly the A320 and had no interest in upgrading for the short time I had before retirement.
The 727 was an outstanding plane, but the DC9 was too, because it was ahead of it's time with no flight engineer. These planes were built like relative tanks. In comparison, modern fly by wire aircraft have a tough carbon skin, but when the limits are exceeded, you have things like tails coming off, which would not happen to a 727 or a 9 because relatively speaking, as they were a bit over engineered. As an example, a coworker's son was racing a carbon frame bike, and crashed. He said that bike blew apart into pieces. Aluminum does not do that, it bends instead.