An iced up aeroplane is comparable to a gymnast who’s handcuffed and chained down to the ground with a 100 lbs weight then expected to perform an Olympic-worthy performance.
So without a doubt, ice is bad business.
Have you ever tried to carry an ice block? I have, and it’s pretty darn heavy. This is the first problem with having ice on your aircraft: It added unnecessary and unaccounted weight to the aircraft.
On an aeroplane, every pound of weight is religiously checked for and people will shed as much as they humanely could, which is why if you carry a lot on a flight, you have to pay extras.
Weight is critical.
An aeroplane does not weight itself, instead, its Flight Management Computer (FMC) will deduce the gross weight of the aircraft through data input by the pilot based on the formulae:
EmptyWeight+FuelWeight+Pax+Cargo=GrossWeightEmptyWeight+FuelWeight+Pax+Cargo=GrossWeight
Which will give a pretty close approximate enough for safe operation.
But remember that an airliner is big, and an accumulation of ice all over the aircraft can clock in a weight of several hundred extra pounds.
Unaccounted weights make the aircraft fly less efficiently and major calculation errors can be made such as wrong take off speeds and a myriad of other critical data. Needless to say, that’s the recipe for a total disaster.
The second thing: This is what airflow through a normal wing is like compared to an iced up wing.
On a clean wing the airflow is smooth, creating optimum lift for the aircraft.
A frosty wing, on the other hand, will break up the airflow and create turbulent streams, reducing lift greatly and can result in a stall.
A stall is the worst situation an aeroplane can ever get into. It is when lift is lost completely and the aeroplane will begin to go on a steep dive.
This is a 747 in a fatal stall, recorded in 2013 by dashcam of a road vehicle in Bagram. Seconds later the plane crashed into the ground, erupted into a fireball killing all crews on board.
It is definitely not what you want to happen when you’re on a flight.
Third problem: They will clog up all of your control surfaces, worst case scenario is that you will lost control of the aircraft completely.
On an aircraft you have several control surfaces that will help you orient your flying metallic tube wherever you wanted it to go.
Flaps and ailerons will help you control the roll of the aircraft, or the rotation of left and right of an aircraft. In other words, flaps and ailerons will help the aircraft turn.
The flaps and ailerons can be frozen solid and refused to move and do their jobs when, for example, the aircraft is passing through a humid and subzero region. Rain drops or palpitation can form on the wing and frozen them up if the pilots forgot to flip on the deice switch.
Result is that you can’t bank.
They’re the giant, moving pieces you can see here. It’s always interesting to see first time flyers freaked out because they thought the wings are falling apart as these moved.
This is applicable to all of the surfaces on the aircraft, you’d technically still be lucky if you only have your flaps and ailerons offline.
Just pray a lot that other surfaces such as elevators and rudder won’t follow suit.
Then there’s the tail (or as we nerds would like to call it: Empennage):
Empennage includes a giant vertical triangular piece which is called the vertical stabiliser and two side pieces sticking out that are called horizontal stabilisers.
Not only do they help controlling the yaw (Rudder on the vertical stabiliser) and the pitch (Elevators on the horizontal stabilisers), as their names suggested: They also help providing stabilisation to the aircraft.
How? By generating a downward force that will balance out with the upward lift from the front wings.
Ice has the same effects on the tail assembly the same way they do with the front wings.
They will dramatically reduce lift the empennage created and can result in a tail stall and force the nose downward, of course, again:
A fatal stall of a C-17 in 2010, no survivor.
They will also do a toll on critical instruments of the aircraft such as pitot tubes which are important to determine the air speed of the aircraft, resulting in a wrong calculation of airspeed. If the aircraft was flying manually, the pilot might notice a discrepancy and correct it.
Big troubles would occur if the aircraft was on autopilot and the computer might try to correct the thrust to bring it up to set speed.
Fuel lines and vents can also be frozen leading to a fuel starvation. I don’t need to explain how bad this is, do I?
All in all, remember to flip the deice switch if you see snowflakes around you. Don’t be like the pilots on Air Florida Flight 90.
The pilots failed to active the deice system. This mistake led to the improper calculation of Engine Pressure Ratio (EPR) and ice buildups on the wings.
Thirty seconds after the jet was airborne, it stalled and crashed straight into the Potomac, resulting in 78 casualties, 9 injuries with only 5 final survivors.
Author – Matthew Lee
