Dick, some real world experience from Bob Buck when he was with TWA, from “North Star Over My Shoulder”.
Later, so-called nonicing carburetors were developed, but they weren't; then came fuel injection, and that was supposed to be the ultimate cure, but it wasn't. An engine needs air, and that comes in from the outside, bringing along snow, rain, freezing rain, or whatever else is out there. The carburetor might not ice, but the induction system-all the passageways the inbound air flows through-will.
A new model Constellation came with fuel injection and consequently was announced as "nonicing," but we still had trouble because the induction system would collect snow that made the engines run erratically. What we needed was a way of shutting off the air coming from outside and taking it instead from under the cowling where it was warm and snow-free. The problem was that the airplanes didn't have this option, known as Alternate-A (A for air). We pilots urged the company to modify the airplanes, but they didn't want to-it cost money.
Every time we encountered snow as we flew across the ocean the engines acted up. The flight engineer played with different power settings, leaned or enriched the mixtures, anything. We flew on with the engines surging-running irregularly, but running. But it was damned disturbing to feel the rough-running engines, on instruments, with the cold, stormy North Atlantic 17,000 feet below. No one ever had a complete failure because of it, but there were no guarantees, and each time it occurred you squirmed, hoping this wasn't the one.
The solution was simple, and it came about on a flight I happened to be flying, New York to Shannon, Iceland, and Paris. One passenger was John Collings, our VP of operations, a thin-lipped old-time pilot who demanded perfection. International operations had recently been combined with domestic, which had been his bailiwick, so now he was boss of it all. Ocean flying was relatively new to him, and I think he may have had that uptight feeling people are apt to suffer when first heading out to sea.
We were about 100 miles off the coast of Nova Scotia, flying through light snow when I drifted back to the cabin for my smile-and-nod session with the passengers and to look in on John. I knew the snow would become heavier as we approached a low-pressure area. He was eating dinner.
He asked me, "How's it going?"
I kneeled down in the aisle and responded, It's going fine, right on flight plan, a little snow outside-we're 100 miles off the Nova Scotia coast."
Just then the engines decided they weren't happy with the snow and started to run rough.
'What's that?" John nervously asked.
"Oh, just snow making the engines act up---can't help it." I didn't feel comfortable and wanted to go back to the cockpit, but I decided to grind this into John a bit.
We chatted some more, as the engines' normal rhythm was disturbed by roughness.
"Don't you think you ought to be up front?"
It won't do any good-I've got a good flight engineer, he's doing his best; without that Alternate-A we can't do a hell of a lot to help." He was well aware of our demands for this modification.
The engines continued their slight surging-Collings looked nervous.
Bob, I want you to go back up front!" it was an order.
"Okay-see you later." And I sauntered back to the cockpit-glad to be there.
We finally flew out of the snow and the engines settled down to their smooth pounding. But not long after that trip the order went out for Alternate-A to be installed on the fleet.