Capt Zimmerman made a terrible error here. His assumption that he HAD TO dump fuel to get down to max landing weight was incorrect. Maximum landing weights are related to tire and brake assembly warranty periods and have nothing to do with safety. He was in position to have it on the ground within five minutes when he broke off his approach to the south to head back out over water to accomplish this totally unnecessary task. Terrible training by Swissair.

Thanks for your comment Captain Bates. I agree with you. The swissair checklist which was found to be too long during the investigation, was shortened by the airline after the tragedy. I always felt that precious time was wasted when it was decided to take the aircraft back over the ocean rather than bringing it directly into Halifax. They could have dumped fuel over land as they came in.

I also agree. When Capt. Zimmermann decided to turn and dump fuel the plane supposedly was over 20'000ft at 30Mi to Runway. At ~250kts, a very rough estimate might put out a descent rate of about 4000fpm. Not impossible but also not comfortable. (correct me if i'm wrong)
They would have had to start that descent immediately at that point. But they should have started descending at a higher rate from the beginning. I'm guessing they were just never aware of the scale of the problem or were just to hooked on completing the checklist before they start the final approach.
What i don't understand is, why the manual (also at that time) hat do be so explicitly when it came to smoke in the cockpit. Smoke in the cockpit should always be a reason to do an emergency descent and land as quick as possible.
Smoke usually means fire and fire in a plane is never good, so why bother trying to find the source with a checklist. Honestly you would barely find it. After every check you would have to wait 5min to see if the amount of smoke decreases. Realistically you could do 4 Checks in the same time you would need to land.
However it was a horrible event and a sad loss of 229 souls. May all of them rest in peace.

Thanks Jack, I agree with your every word. Thanks for summing it up so well.

Barbara