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Thread: Any pilots here?
02-14-2009, 06:47 PM #1
Any pilots here?
I was just wondering if there were any pilots here in the forum? I started takeing my privates when I was working for a friend running a ground spray rig for him. He had a air tractor turbo prop, an air cat with a 600 HP Pratt & Whittney radial, then his 172 cessna skyhawk we used for a scout plane. Any how when the drought hit things went belly up and the bank took the planes so there went my free ride and I couldn't afford plane rental to finish my lessons.
I've logged 75 hours flight time only flying VFR. My boss and I were heading back from Norton Kansas to Goodland Kansas and it was winter late at night and we hit some fog. My boss who had IFR rateing was piloting the plane back to Renner field. And we were about 40 miles NE of the airport and we noticed our wings were starting to ice up and we could no longer maintain altitude. We were flying about 6,000 above the ground and it was just a gradual derease in altitude and we made it back to the airport just fine, however when we landed we had a fixed gear and did not use the flaps.
I was just wonder about the plane crash, how the pilot didn't have any clue that there was that much ice build up on the wings. If it was bad enough that he lost all lift when applying his flaps you think he would have had trouble maintaining altitude way back in the flight. I'm just speculating I don't have that much experience flying and definatly not any twin engine aircraft. I was just wondering if there was anyone with experience here that could clarify this for me.
02-14-2009, 11:03 PM #2Regular Guest
- Join Date
- Nov 2007
- North Texas - DFW area.
When an airfoil (airplane wing) gets a deposit of ice, the ice tends to adhere to the skin of the wing and follow the upper surface of the wing (camber) due to the laminar airflow flowing over the wing surface. Naturally, the stall speed of the aircraft can be raised significantly when ice is present on a wing.
As long as the airplane's air speed is greater than the newly-raised [yet unknown] stall speed due to a coating of wing ice, the plane can continue flying, up to a point.
The heavy loading of ice on the complete airframe of a small general aviation airplane can cause a plane to lose altitude with the throttle at max. Think of it as slowly adding the equivalent weight of couple of passengers and/or luggage to the passenger compartment as ice builds on the skin of the plane. The engine is only so powerful and the wings can generate only so much lift. Besides, the wings are getting coated with ice and the ability of the wings to generate lift is slowly diminishing as the wing ice builds in thickness. The airplane can continue to fly, but it can be a losing battle with gravity.
Also, that plane (Cessna 172?) you were flying in could have had propeller icing. Prop icing can cause the air foil (spinning propeller) to have decreased thrust (lift). Lesser thrust from the prop would be the same as decreasing the throttle. Less thrust and the plane would slowly sink. Maybe the carb intake was slightly iced and a decrease in engine power would have resulted. I'm just taking a stab in the dark for I don't know what happened in your situation.
An aircraft that is experiencing a buildup of ice that is greater than the deicing equipment can remove from the wings, propellers, etc. is in a dangerous state. The pilot, whether he/she likes it or not, has become a TEST pilot.
When a pilot introduces an aerodynamic input to an ice laden aircraft, this can "upset the apple cart" and cause an out-of-control situation to develop in a matter of a few short seconds. Any of the following pilot-induced inputs can cause an aircraft to go out-of-control in an aircraft experiencing heavy icing:
- slowing down the aircraft to below the newly-raised [yet unknown] stall speed
- extending the landing flaps at the trailing edge of the wings to increase lift a slower air speeds
- lowering the landing gear
- extending leading edge wing slats for greater generated lift
- abrupt control inputs such as sharply banking the wings or pitching the nose causing a high speed stall
- disengaging the autopilot while airfoil control surfaces are greatly deflected (unknown to the pilot at the time the huge amount of deflection present) due to autopilot demands when a build-up of wing ice causes extreme control surface movement to keep the aircraft flying straight and level in the intended direction
Imagine that you are flying heavily iced in a traffic pattern to land at an airport (and, naturally, you are flying low and slow). If you run into trouble and gravity starts taking over due to decreased airfoil lift, you don't have enough altitude or airspeed to recover from the stall. Remember, the stall speed is higher and the pesky old ground comes up to meet you before a greater airspeed can be attained to get the wings flying again. [A stall can happen in the traffic pattern whether an aircraft is experiencing icing or not. I am talking about icing conditions.]
There was a twin turbo-prop passenger plane that crashed near Roselawn, Indiana in 1994 due to severe icing. The plane was being held by air traffic control at 10,000 feet altitude when the autopilot was disengaged by an uncommanded roll excursion as it was descending to 8,000 feet. The plane immediately experienced severe and abrupt out-of-control movements followed by a rapid descent to earth.
1994 Roselawn crash
Tiger93rsl, I hope this helps. This is not meant to be a treatise on the fundamentals of aircraft icing. Just some ideas and info to help answer your questions.
02-15-2009, 12:36 AM #3
Great explanation! I have 42 hrs in a cessna 172. Passed my written and was working up for my checkride when my instructor got busy and then relocated and I moved to the beach. My wife wants me to finish my license... but i told her I need to retake the ground class. Been to long since I flew. (like 8 yrs ago).
I miss it and all these purdy days we get out here makes me cry!Silent Service........ Death From Below!
Somewhere in Kansas, a town found a village idiot!
02-15-2009, 01:02 AM #4
Yes thank you for the explanation. And it was a skyhawk we were flying in. And the iceing was definaly on the wings and not the prop. but it was a smooth even film of ice matching the airfoil. I was just going thru the logs I kept I only have 28 hrs. I can get credit for the remaining 22 hrs. can't be counted. I would like to finish, I relly enjoy flying.
02-15-2009, 06:30 AM #5
Twilli used to be test pilot for the CIA and flew classifed aircraft. Twilli is still not allowed to talk about itNo Heat No Cool You need Action Fast
02-15-2009, 09:02 AM #6
02-15-2009, 10:13 AM #7
Commercial, Instructor (including Instrument and Multiengine) with turbine (Learjet) time.
If you are flying VFR, you should be far enough from any water vapor that icing is not an issue. Usually, icing is an IFR (Instrument Flight Rules) issue.
The first thing to do when you notice ice accretion in a plane not certified for known icing (like a 172) is to get out of it. Usually, requesting an immediate descent to minimum altitude is in order. Don't wait.
When you have ice on the wings of a 172, you have it in other places, even if you can't see them. The prop isn't heated, so yes, you DO have ice on the leading edge of the prop, which immediately begins to degrade the ability of the prop to pull the airplane along.
And, even worse, you have ice building up on the air intake for the engine, that rectangular area with the screening under the prop. You could be descending and suddenly you have a windmilling prop, and no power. That's when you request a vector to the closest field, and you declare an emergency.
There are three types of systems to handle icing.
On many jets, including the two Lear models I flew, we have a "hot wing." Air is "bled" from the engine compressor and piped to the leading edge of the wings, etc, to prevent ice from forming.
Some planes can't afford to lose the power associated with a bleed air system, like the Hawker HS125. It uses the same size Garrett engine as the Lear, but it is a much larger aircraft, so instead of a hot wing, it uses a "weepy wing," a system of deicing fluid that is "weeped" through tiny holes to wash away ice as it forms. It's called the TKS system.
The most common system for flight in known icing is the "boot" system used on Barons, King Airs, Conquests, Navajos, and the Dash 8.
In another thread about the crash outside Buffalo, I theorized that since the Dash has a good record for operations in icing, either the system did not function properly or the crew did not initiate the system soon enough. Depending on the situation, ice can accrete rather quickly. Most crews are very vigilant about icing.
In the US, pilots are trained to wait between boot activations to allow the ice to build to the point that an activation will clear the wing, because the breaking ice in the boot area will force the breaking of ice BEHIND the boot area. Canada has a different approach, telling pilots to activate the boots upon first notice of icing. Since the Dash is a Canadian built plane (with much of the cost of production borne by the Canadian taxpayer, by the way) the frequency of activation may be dictated in the Approved Flight Manual for the aircraft. Since I have never flown a Dash, I can't tell you that.
I hope that helps.
02-15-2009, 03:39 PM #8
Man. Now I really want to fly! I woild love to get my private... then Inst.... then multi engine. I would love to fly a king and eventually up to a lear jet!!!
I flew the heck out of the F15E simulator while I worked there for 4 yrs at Seymore Johnson AFB.
Yes... it was a blast!Silent Service........ Death From Below!
Somewhere in Kansas, a town found a village idiot!
02-15-2009, 04:52 PM #9
When you have that kind of money, the $1,800 per hour cost of a Lear is not important.
My advice to would be pilots is to join a club that shares aircraft ownership costs, and do it for fun, and not as a career. There are too many youngsters whose parents will support them while they work low paying flying jobs on their way to the job they really want, "airline captain." Until then, the money is absent.
02-15-2009, 07:47 PM #10
02-15-2009, 07:55 PM #11
2. Given the right (wrong) conditions ice can build up very fast. One of the earlier reports I heard on this crash said the pilot reported ice on one of the wings (don't know if this is accurate or the reporter screwed up). If only one de-ice boot was effective it would make the plane very difficult to control.
02-15-2009, 08:31 PM #12
02-15-2009, 08:58 PM #13
My advice to would be pilots is to join a club that shares aircraft ownership costs, and do it for fun, and not as a career. There are too many youngsters whose parents will support them while they work low paying flying jobs on their way to the job they really want, "airline captain." Until then, the money is absent...
Son in Law was a pilot for Continental Airlines till the layed him off and your right, the pay is horrible. Unless you a captain your not getting ahead.I'm not tolerating Political Correctness anymore, from now on it's tell it like it is.
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