ChrisKSDF said
My whole point was that asking a pilot to perform a VOR/DME approach in conditions very near VFR isn't exactly "irresponsible" or dangerous.
Initially beginning to look very much like this RJ100 tangled with freezing rain (aka rain-ice) during the protracted time spent at low-level on that drawn-out approach (temp zero and dewpoint zero from the ATIS more or less confirms that). Allegedly ATC always motor them around via some lengthy track-miles even before they get to commence that 28 VOR final approach. They would have accumulated a lot of ice very quickly in the rain and snow conditions. In fact they would have quickly become a flying ice-block. Those ex Chinook helo engines aren't renowned for coping well with heavy icing conditions (although they are anti-iced, that bleed-air fed system could be overcome at lower power settings on the approach). But more to the point, not many aircraft can cope aerodynamically, for any period, with freezing rain/snow - because it tends to hit and stick in areas on the wings, tail and fuselage that just aren't able to be de-iced. It is accumulative. That build-up can rapidly erode the aircraft's aerodynamics (lotsa drag, increased weight and a greatly increased stall speed). The pilots may not have realised just how much their stall speed had increased. When the laminar flows are disrupted by the non-laminar formation of rime ice accretions and ice-ridges (just aft of the de-iced leading edge areas) and ice excrescences (caused by melted ice flowing back and re-freezing further aft) then the stall IAS can zoom up and the stall warning can then be as little as a few knots. In part that is because the horizontal tail surfaces (elevator and horizontal stabilizer) are also affected. It is normally the vibration over the tail that warns you about pre-stall airflow breakaway occurring prematurely (speedwise) on the wing - but with a high-up T-tail, I'm not sure that that would be the case. When the freezing level is very close to the ground (or lowest safe altitude in IMC) you cannot escape rain-ice (by descending into warmer air) - so the only answer is in diverting, preferably before you get caught up in this deteriorating condition.
It's possible that they might have stalled it when levelling early at MDA for the drive into the MAP or even on an attempted missed approach (i.e. during flap retraction). That's
exactly when that heavy coating of draggy rain-ice and greatly increased stall speed is most likely to catch you out. T-tail deep-stall might have been part of it. They obviously hit quite flat so that either means stalled or ran outa power. If they'd simultaneously had engine problems I'd not be surprised. These RJ-100's have the LF-507 engines (which allegedly don't suffer from roll-back, but that's not to say that they would behave impeccably in heavy rain-ice. Spent a bit of time in freezing rain and I know just how fast things can turn to worms, if you don't get out of it pronto. The problem is that, being night-time, they wouldn't have been monitoring the wings visually, nor necessarily noticed the ice build-ups on the windshields. Someone mentioned that the dive-brake was about 80% deployed. They likely did that so that they could carry more power for better wing de-ice. However in freezing rain (that just hits and sticks), that's not going to assist at all.
If they'd been able to slot straight into an ILS there'd have likely been no problem. I blame the bureaucrats and their compulsory 28 approach - totally idiotic in those weather conditions. In fact, I'd go so far as to call it criminal stupidity.