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Question for 737 pilots

PAPA FOX!

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I was visiting the UK B-737.org technical site and reading about the ice protection and saw no mention of what min airspeeds to use while flying an approach with ice on unprotected surfaces. Does your company manual specify any faster speeds in mod-sev ice when it is below freezing to the surface?


I had also wondered if there has ever been a large or heavy jet brought down by ice much like in Roselawn 11 yrs ago? I don't recall any. Also could the 737 have withstood the same conditions in Roselawn since it has hot wings among other means. Other than not taking off with other than a clean wing it seems it could withstand even severe ice for long enough to easily change altitude. Am I correct in than no aircraft no matter how large is allowed to fly in FZRA or FZDZ?
 

viper548

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even with ice protection, you're supposed to stay out of moderate and severe icing.
 

firstthird

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our FOM says to add 10 knots to your approach speed if you are accumulating ice on the approach, although you are supposed to bleed that off below 300 feet back to your original Vref.
I think that most planes (besides NASA testers there on purpose) stay out of FZRA and FZDZ, but I'm sure someone more erudite will enlighten us further.

Something interesting about the 737 (or at least I think so) is that we have no anti-ice or deice on the horizantal stabilizer. I've never really gotten a good answer why. I've heard the disturbed air off the main wing prevents ice from forming back there but who knows.

the NG 737s also have a limitation not to hold in icing with the flaps extended.

Is Roselawn the ATR that crashed in holding?
 

TrafficInSight

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PAPA FOX! said:
I was visiting the UK B-737.org technical site and reading about the ice protection and saw no mention of what min airspeeds to use while flying an approach with ice on unprotected surfaces. Does your company manual specify any faster speeds in mod-sev ice when it is below freezing to the surface?


I had also wondered if there has ever been a large or heavy jet brought down by ice much like in Roselawn 11 yrs ago? I don't recall any. Also could the 737 have withstood the same conditions in Roselawn since it has hot wings among other means. Other than not taking off with other than a clean wing it seems it could withstand even severe ice for long enough to easily change altitude. Am I correct in than no aircraft no matter how large is allowed to fly in FZRA or FZDZ?

I know nothing about the accident you're talking about but search for "Palm 90"
 

FN FAL

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firstthird said:
Is Roselawn the ATR that crashed in holding?
For some reason I seem to remember ASA had an ATR icing crash as well, near Detroit. Maybe I'm wrong.

My management tells me that the ATR has the same NACA airfoil as the Caravan.
 

PAPA FOX!

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FN FAL said:
For some reason I seem to remember ASA had an ATR icing crash as well, near Detroit. Maybe I'm wrong.

Yes, but it actually was an e-120. Here is the NTSB report.
 

Launchpad

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"I had also wondered if there has ever been a large or heavy jet brought down by ice much like in Roselawn 11 yrs ago?"


Check Air Florida in DCA a few years back, although that was more engine inlet ice than airframe ice.
 

Pat Fabin

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The NG airplanes also automatically increase your approach speeds 15knots if you've used wing anti-ice during the flight and land flaps 30 or 40.

But, I'd see more ice in one day flying around in my 1900 over Lake Erie then I've ever seen in 7 years flying jets....we just dont spend much time flying low, and the ram rise from flying faster keeps the skin temperature higher as well, which helps. The min icing speeds I've seen in turboprops are usually in the 150-170 knots range and if we're flying that slow we're landing or rotating.

The Palm 90 crash was icing-related but only in the way it caused false engine indications and the crew never set takeoff power. There is every reason to believe the airplane would have flown that day had they turned on the engine anti-ice or simply pushed the power up. A sad set of circumstances indeed.

-PF
 

Dangerkitty

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TrafficInSight said:
I know nothing about the accident you're talking about but search for "Palm 90"
That wasn't due to airframe ice. The engine's iced up on the ground when the crew didn't turn on the engine anti-ice. Thus, on take off the EPR's read artificially high and the aircraft took off with about half of what takeoff power should have been.
 

TrafficInSight

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Dangerkitty said:
That wasn't due to airframe ice. The engine's iced up on the ground when the crew didn't turn on the engine anti-ice. Thus, on take off the EPR's read artificially high and the aircraft took off with about half of what takeoff power should have been.
1.7 epr versus 2.04 , but airframe ice was probably also a factor:

'Palm 90' then proceeded to taxi into position behind a New York Air DC-9, the last of sixteen aircraft in line for takeoff. With a light snow still falling, Wheaton decided to use the hot exhaust from the preceeding DC-9's engines to melt the snow off the wings, which in the end only had the effect of pushing it to the trailing portion of the wing to refreeze. The aircraft's anti-ice system was unable to de-ice this portion of the wing.
At any rate the original question was wether ice had ever brought down a heavy and the answer is yes.
 

PAPA FOX!

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Dangerkitty said:
That wasn't due to airframe ice. The engine's iced up on the ground when the crew didn't turn on the engine anti-ice. Thus, on take off the EPR's read artificially high and the aircraft took off with about half of what takeoff power should have been.

You'd think any competent crew would have X-checked the EPR with EGT, fuel flow, and N1, not to mention the easily noticable sensation of accelrating very slowly! There was a near accident in some pacific island when a 732 had the EPR probes (both) covered by some fine powder due to some kind of mining nearby and they cleared the rocks off the dep end by some 5 to 10 feet!
 

Dangerkitty

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PAPA FOX! said:
You'd think any competent crew would have X-checked the EPR with EGT, fuel flow, and N1, not to mention the easily noticable sensation of accelrating very slowly! There was a near accident in some pacific island when a 732 had the EPR probes (both) covered by some fine powder due to some kind of mining nearby and they cleared the rocks off the dep end by some 5 to 10 feet!
If you listen to the CVR tapes you can hear the FO state a few times during the takeoff roll that something doesn't look right. He then kinda talks himself into thinking everything is OK. The rest is history.
 

Launchpad

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PAPA FOX! said:
You'd think any competent crew would have X-checked the EPR with EGT, fuel flow, and N1, not to mention the easily noticable sensation of accelrating very slowly!

They would, these guys didn't. If you ever listen to the CVR stuff from Air Florida, they make some comment about how engine ice and ice protection in general is just a myth.... There is a whole discovery channel show about the crash and rescue. Gross pilot error.

Word-
 

PAPA FOX!

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Here's the article about the above incident. Brace yourself because the end of the article will ANGER you very much.
 

FN FAL

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T-Gates said:
And the airline was Comair, not ASA...
Papa Fox! said:
Yes, but it actually was an e-120. Here is the NTSB report.
Thanks and thanks!
 

NuGuy

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Launchpad said:
PAPA FOX! said:
If you ever listen to the CVR stuff from Air Florida, they make some comment about how engine ice and ice protection in general is just a myth.... There is a whole discovery channel show about the crash and rescue. Gross pilot error.

Word-
I don't think that was jist of what was said on the CVR. I believe their comments were directed to the ground de-icing ops in general, which at the time, weren't organized quite the same way as they are today.

CAL had somewhat of a similar incident out of KDEN back when they had a hub there (icing wise, not crew wise, that is)

But I agree...if your AC uses EPR to set TO power, you should know a ballpark N1 number that is roughly equal to TO power as a cross check. Not just ice, but any piece of crud can fly up into the EPR probe and give you a false reading.

Nu
 
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