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Author
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Topic: 727/737 deicing
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Subsonic Transport
Post Captain
Member # 2139
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posted
While my pilot friend and I hash out what happened to the Q400, he mentioned to me that another friend of his said that the 737's do not have ice protection in the vertical stabilizer and the horizontal stabilizers. I thought he was nuts.
I then started to recall when I took my 727 F/E written many years ago. They are both built on the same technology. I went upstairs and dragged out my 727 maintenance manual from People Express. I opened the book listed under rain and ice. I'll be damned. The 727 is not ice protected on either stabilizer. I was surprised.
Last night at work, I asked a SWA crew if their new 737 is ice protected. There response was "no."
Wow, I never knew that.
So I ask you all....Why?
Posts: 407 | From: Buffalo, NY
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Tom Girtman
Post Captain
Member # 1021
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posted
It is because Boeing tail stabizers were Swept wing!
Posts: 169 | From: Buckingham, Pa.
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Glasspilot
Post Captain
Member # 390
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posted
I was a 727 Capt. from 1998 till they parked them Sept 2000.
Once we were landing in STL, lots of rime ice in the clouds. We had all the deicing equipment lit up. As we went to landing flaps I noticed the elevator felt weird, very light in the yolk. I told the F/O and engineer I was adding 10 knots because of possible ice on the tail.
After pulling into the gate I went down to the ramp looked at the tail and it was covered with inches of rime! Makes you wonder how Boeing and the FAA thought they didn't need any systems back there!
Posts: 263 | From: Outer Banks, NC
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Subsonic Transport
Post Captain
Member # 2139
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posted
Yesterday I spoke with a UAL airbus crew. The Airbus does not have protection either. I'm still waiting for info on the MD95.
[ 02-26-2009, 21:27: Message edited by: Subsonic Transport ]
Posts: 407 | From: Buffalo, NY
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jpp
Post Captain
Member # 2913
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posted
757/767 does not, either. Boeing apparently says it's not an issue!
Posts: 41 | From: lga
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Subsonic Transport
Post Captain
Member # 2139
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posted
I spoke with an Airtran pilot last night and he advises me that the B717 is protected on the horizontal stabilizer with hot air.
Was/is the DC-9 and the MD80 series protected the same way?
Posts: 407 | From: Buffalo, NY
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Bob Ritchie
Post Captain
Member # 1035
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posted
Yes....
They have heated tail anti-ice; just like the wings. It was less of an issue on the DC-9 as the tail would carry a good load of ice. By the time it was streached into an MD-80....tail ice became more of a concern.
I do not recall that tail icing ever created a problem on the DC-9/80 series. Not to say that it never occured.
There were several instances of ice forming on the wings of MD-80s, while on the ground, due to cold fuel in the tanks. Before the problem was resolved by visual inspection and eventualy installing heated blankets...there were a number of take off crashes resulting from the ice formation. TWA and other airlines had a couple of incidents where the ice shed off and caused severe engine damage. Not a problem on the DC-9s.
15,000 hours in type, much of it throughout the midwest. Never worried about ice. Although one time going into Anchorage.... the heated windshield glazed over completely while decending on approach. By the time we were on final I had about a 10" circle of clear windshield.
Bob
[ 03-04-2009, 09:36: Message edited by: Bob Ritchie ]
Posts: 1733 | From: Warren County, Missouri
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Glasspilot
Post Captain
Member # 390
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posted
quote:
Originally posted by Bob Ritchie: By the time we were on final I had about a 10" circle of clear windshield.
Sounds like my old 1969 Beetle! Once the heat/defrost system rotted out you had to blow hot air from your mouth at it to see out! (Upstate NY)
Bob, it must have been REAL cold up there for the windshield heat to have been overpowered like that!
Andy
Posts: 263 | From: Outer Banks, NC
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Subsonic Transport
Post Captain
Member # 2139
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posted
I remember working Continental when the wing ice situation developed on the MD80's. If I recall correctly, their were strings attached to the wing, in the wing root area and if they moved freely, no ice. If not, get the glycol or wait for the fuel to warm up. Isn't his why TWA put the black stripe on the wings? If it's rough, no ice, if it's smooth, ice.
Posts: 407 | From: Buffalo, NY
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dave carr
Post Captain
Member # 783
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posted
quote:
Originally posted by Subsonic Transport:
I remember working Continental when the wing ice situation developed on the MD80's. If I recall correctly, their were strings attached to the wing, in the wing root area and if they moved freely, no ice. If not, get the glycol or wait for the fuel to warm up. Isn't his why TWA put the black stripe on the wings? If it's rough, no ice, if it's smooth, ice.
Management also gave us a ladder and a broom stick. The ladder was on wheels and we had to push it up close to the leading edge of the wing and then climb the ladder. Once perched upon the ladder we then leaned out with the broom stick and moved the strings. If the strings moved we were good to go. If the strings were frozen to the wing and wouldn't move then the wings had to be cleaned. I remember doing that in such places as ONT and SNA on warm sunny days.
This caused some problems with the ground personell. As pilots we were required to inspect for ice but the ground folks were required to move the ladders. This caused some interesting conversations. Also some stations purchased good solid ladders but they were heavy and hard to move around. Other stations bought the cheapest junk they could find and climbing to the top of one of these K Mart specials was not one our favorite things. Ah---the memories.
Dave Carr
Posts: 232
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Subsonic Transport
Post Captain
Member # 2139
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posted
I always wondered why the MD80 series had this problem. I knew that the 727 had fuel heat. The description is as follows courtesy of People Express:
Fuel and oil flow:
Metered fuel, from the fuel control, passes throught the core tubes to absorb the heat from the oil. The hot oil passes around the tubes and is baffled to pass back and forth across the tubes 14 times to give the maximum exchange heat. The cooler oil then travels to the engine bearings and seals.
Fuel Temperature Indication Circuit:
Fuel temperature information is useful in assessing hot-fuel climb performance, oil cooling capacity [engine and hydraulic], fuel icing from water contamination, and possibility of fuel freezing.
There is no mention of over the wing icing. Cause there isn't any.
Posts: 407 | From: Buffalo, NY
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Bob Ritchie
Post Captain
Member # 1035
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posted
Sub,
Most jets have fuel heat, including the DC-9/MD-80 series. It is two different subjects. I believe your reference is fuel heat associated with ice formation in the fuel filters, etc.
The ice on the wings of an MD-80 is a refrigeration effect. One of cold fuel in the tanks making the surface of the wing very cold and therefore forming ice on the wings.
Bob
Posts: 1733 | From: Warren County, Missouri
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Subsonic Transport
Post Captain
Member # 2139
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posted
I do realize the difference between internal ice and the over wing ice. I think I assumed that if the fuel was at or above freezing, ice wouldn't form over the wing.
I'm trying to remember why the MD80's had over wing ice. All I can remember was something structural.
Posts: 407 | From: Buffalo, NY
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Glasspilot
Post Captain
Member # 390
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posted
quote:
Originally posted by Subsonic Transport:
I do realize the difference between internal ice and the over wing ice. I think I assumed that if the fuel was at or above freezing, ice wouldn't form over the wing.
The fuel heat does not heat the fuel in the tank. It heats the fuel on it's way to to a fuel filter. Filters sometimes start to clog up with particals of ice and the fuel heat simply clears this up. It has nothing to do with wing ice.
quote:
I'm trying to remember why the MD80's had over wing ice. All I can remember was something structural.
Pilots always expect ice when it's cold outside but MD managed to design a wing that would create ice when the weather on the ground is such that you wouldn't expect it!
Lets say an MD-80 flies a leg at altitude long enough that the fuel gets very cold. Now it lands at an airport with high humidity and pulls into the gate. As water vapor comes into contact with the top of the wing sometimes water would condense and then freeze. It so happens ice would form on the wing directly in front of the engine inlets.
Now the aircraft rolls for T/O and just at rotation the ice would break off and go right where you don't want it to go. After a few of these incidents the FAA had us checking for ice. And eventually a wing heater blanket was developed to solve this problem.
Fun, Uhh?
[ 03-08-2009, 18:02: Message edited by: Glasspilot ]
Posts: 263 | From: Outer Banks, NC
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