Last night I had a pretty scary landing at KORD.

The flight was from KDCA to KORD. Estimated time 1:36, actualy about 2:00 with a 51kn headwind. Plane was the Leonardo SH MD-82

Takeoff was a bit tricky becuase of the weather.

KDCA 090852Z 33014G21KT 10SM SCT036 02/M03 A3019 RMK AO2 SLP222 T00171028 53008

With snow on the ground and the fact the md-80 is known for its icing problems I called for a ground De-Ice on the ramp after engine start. They proceded with type 1 and 4 fluid. After complete the flight controls were fully responsive. Being 3-4am my time I proceded to I direct take off doing a 30 second run up of the engines at 70N1 per procedure to clear de-icing fluid from the engines. Take off roll was supprisingly long but I didn't put much thought into it.

ZFW: 111710lbs
FOB: 26300lbs
GW: 138010lbs

Planned Reserve Fuel 8000lbs.

Estimated fuel usage was abut 18.3lbs.

Engine and Wing Anti-Ice was on the entire flight, fuel heat was used about 3-4 times every time the fuel dropped near 0c.

ATC assigned me visual runway 28 at KORD with the weather

KORD 091151Z 25005KT 8SM CLR M06/M08 A3025 RMK AO2 SLP255 T10611083 11039 21061 56005

About 5000 feet I went manual and completed the approach checklist. This is where I noticed the overhead annunciator panel was displaying "L ICE PROT TEMP LOW"

I opened the QRH and folled the checklist.

Quote:


Here is where I can only assume Ice build up on the left wing.

Approaching 3000ft I am fully configured for landing. Flaps 28, 20knts above vref.

Landing weight estimated about ~119700 rounded up to 55 metric tons giving me a landing speed of 135knts. I added 10knts for icing conditions making it 145knts.

Around 1500 feet I began to decend below glideslope and gently puled back on the yoke to find the plane barely responded. With full deflection of the yoke I was able to maintain glideslope but was unable to climb.

I debated on calling for a go-around but I feared the ice would only be worse if I was able to gain power.

Odd thing is, Ailerons were very responsive, it was only the elevators that would not respond.

I maintained centerline and relized at 200 feet I would not be able to flare the plane. After calling landing I mentioned the landing would be rough. Touchdown was similar to a autoland, just slightly rougher.

My questions are,

1. Did I make the right call continuing the landing and would a go-around have caused a fatal stall?
2. Should I have reported the failure to ATC?
3. What could I have done better to prepare myself for severe icing conditions?

Thank you,

Aiden

EDIT: I just remembered, I left the aux hydraulic pumps on the duration of the flight as well as the hydraulic were set to high instead of low. However, hydraulic quantity was normal as well as temperature. Flaps responded normally and gear deployed fine. I do not think it was a hydraulic issue.

I agree with Dave that "8SM CLR" eliminates the possibility of icing because of the lack of visible moisture.

Just to add to his comments about the pitot tube freezing, when icing conditions actually exist, the static ports can also freeze over. In an airliner or any other aircraft equipped with heated pitot tubes, it is probably more likely that the static ports will freeze, particularly in freezing rain. Pitot-static operated instruments (airspeed, altimeter, and vertical speed) will be affected. The air data sensor will also be affected by frozen pitot tubes and static ports, and may have started the chain of events that lead to the crash of that Air France airplane into the Atlantic Ocean.

Art

As far as I know, the only time ice can form without visible moisture is when the air is below freezing and supersaturated and there are no condensation nuclei around which the ice can form. I think this combination is most likely in the Arctic where the air is cleaner.

I suppose that the engine ice is to be on is because as the air enters the curved nacelle intake, its temperature drops to and below the dew point (just like in a carburetor), and ice can form there. I don't remember ever having ice form on the wings under the same conditions.

What I said about pitot tube icing was just to complete what Dave had mentioned. With no visible moisture and your pitot tube heaters on, I'm sure that pitot tube icing wasn't the issue.

There was a forum question about icing under similar conditions either here or on FlightSim.com some tme ago. I don't remember how it turned out.

Art

You will probably find FAA Advisory Circular 00-6A - Aviation Weather For Pilots and Flight Operations Personnel interesting:
http://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document...

Before even reading the other replies, my first thought after reading your description of events was tailplane icing.

I know very little about the DC-9/MD-80. Real world I am a C-141/C-5/DC-10/737 guy. I can tell you from my 141/C-5 days that t-tails in and of themselves tend to be very susceptible to tailplane icing. If descending through clouds in icing conditions, we had the anti-ice on well before entering the clouds. (Of course, that went for my other airplanes, as well.)

Remember that the horizontal stab applies down-force on the tail in a stable aircraft. An iced-up stab will tend to cause a pitch-down moment. The nose will drop. That's why the landing procedure calls for a partial-flap landing: flap extension also causes a pitch-down moment. The fact that you were unable to pitch up either on approach or in the flare strongly suggests tailplane icing.

I do know that the elevators on a DC-9/MD-80 are un-powered. Ever notice the elevators flapping in opposite directions while it sits at the gate? They'll streamline once they get some air moving over them. If your servo-tabs were frozen, full-deflection on the yoke would have zero effect on your elevator. You did good carrying the extra airspeed. Without it you might have had a full tailplane stall and an unrecoverable situation. (Remember Colgan Air 3407? A Dash-8 T-tail. The pilot lost it after he deployed the flaps on approach.)

As for the idea of pitot-static icing, I doubt it. You had pitot heat on, and in transport category aircraft, the static port is also heated, so unless your airspeed readings were stuck at 270-300 knots (your cruise IAS), they were probably correct.

From FAA Advisory Circular 91-74, Pilot Guide to Flight in Icing Conditions:
There are a number of specific cues associated with ICTS (Ice Contaminated Tailplane Stall) to which a pilot should be sensitive, particularly during this phase of flight (approach and landing). Most of these cues are less readily detected with the autopilot engaged.
*Elevator control pulsing, oscillations, or vibrations (hard to sense in a desktop flight-sim!)
*Abnormal nose-down trim change
*Any other unusual or abnormal pitch anomalies (possibly resulting in pilot-induced oscillations)
*Reduction or loss of elevator effectiveness
*Sudden change in elevator force (control would move nose down if unrestrained)
*Sudden uncommanded nose-down pitch

That's my $0.02

As an aside, I am amazed at the sophistication possible in FS9/FSX. When I was first learning the craft, I practiced instrument procedures on FS5. It was crude, but it worked well enough. But practice system failures? Fuhgedaboudit! Now you've got transport-category aircraft, their systems and their aerodynamics all modeled in high fidelity. I regularly use the PMDG 737 to prep for recurrent. It's cheaper and it works better than the training software the company bought me! Whoda thunk it?