How much snow/ice is allowed on the fuselage of a 737?

[PitotTube]

Hello,

We all know that the wings, horizontal stabilizer, vertical stabilizer and rudder have to be clean for takeoff, but how about the fuselage? I am trying to find guidelines for this but cannot find anywhere.

Airlines that do two-step deicing, do they also put type II or Type IV on the fuselage? I have a hard time believing that.

If anyone knows please add to the thread,
pT

http://cdn-www.airliners.net/aviation-photos/middle/9/3/6/1173639.jpg

[Flight Detent]

My understanding, is that if the particular surface does not produce lift, then there is no requirement to get it deiced.

Cheers...FD...:)

[PitotTube]

But if there is like an inch of snow all over the top of the fuselage it must be pretty significant drag penalty? What does boeing say/recommend about this? Anyone knows?

pT

[Daysleeper]

The whole airframe including the fuselage should be clear of contamination.

There is an exception (but check the individual type as not all types allow it) that allows a thin hoar frost on the fuselage but only to the point where lines and stencils remain clearly visible.


http://www.airteamimages.com/pics/82/82258_800.jpg

[BOAC]

As daysleeper says. There are important things like static ports and other vents/+ out and inlets and what happens to snow in front of the windscreen and engines as you accelerate and where does any melted ice run and gear doors and ....................quite lot to think about.

[Mad (Flt) Scientist]

Technically, the Canadian Regulations would allow contamination on both of those fuselages:

602.11 (1) In this section, "critical surfaces" means the wings, control surfaces, rotors, propellers, horizontal stabilizers, vertical stabilizers or any other stabilizing surface of an aircraft and, in the case of an aircraft that has rear-mounted engines, includes the upper surface of its fuselage.

(2) No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.
(my emphasis)

Obviously, any specific model prohibitions in the AFM limitations would overrule the general provisions of CAR602.11 in a more conservative sense

As to the question of applying AI fluids to a fuselage - a thorny question. Hold Over times are only really validated for essentially "flat" surfaces - what happens to fluids on a curved - or vertical - surface is something that isn't really spoken about ...

[kenparry]

For the Boeings that I've flown, it's exactly as daysleeper said above: thin hoar frost only. That's from the AFM.

[Exaviator]

From my own experience on the B747 passenger aircraft, snow & ice on the fusilage was never a problem on as it is usually melted by the heat being transfered from the cabin. It was only necessary to de-ice the wings and tail plane. The freighter however would accumulate snow on the fusilage and this was also removed prior to flight .

The de-icing crews were very experienced, knew what they were doing and did an excellent job often in very miserable conditions.

The bottom line was keep it clean and if in doubt remove it! :ok:

[john_tullamarine]

There are important things like static ports

Probably not a major concern with most being on the lower surfaces .. but static error changes would be my first worry. There have been occasions involving eyebrow raising/fright where mods forward of the statics have caused unexpected airspeed errors for the test crew doing the qual trials ...

[BOAC]

Well, JT, I guess you have never seen a 737 static port covered in re-frozen melt, then?

As for "mods forward of the statics" a new rule for IB?

Back to fuselage ice and snow - in the UK you have CAA regs to work with, as described by DS plus common sense, which is what the Captain and ideally the rest of the crew are/?were? expected to exercise.

[L337]

Many years ago I arrived at a snow covered 737, and as required insisted that all snow be removed from all surfaces. Including the fuselage.

I made the error of telling the de-icing crew to not de snow the area forward of the cockpit. I could see no harm in not removing the snow from that area.

On takeoff at about 80kts all the snow on the nose blew off onto the windscreen. I was instantly unable to see out the window. A flurry of hands found the wipers, but for a few seconds it was a little fraught.

Learnt about flying from that.

[ShyTorque]

I wouldn't want ice flying off and being ingested into the engine intakes so I'd have it removed.

[TOWTEAMBASE]

try you tube, there are 3 or 4 little videos on there called "caa ice aware", might be of interest

[debiassi]

Also worth considering that icing on the fuselage can be sucked into the engine causing FOD (foreign object damage) or flameout. Chunks of ice if not removed can also fall into crevaces and lodge in places where they could cause damage or control anomalies. Airframes are designed to be flown clean and all relevant performance data is based on a clean airframe.

[groundog]

thickened anti-icing fluids may be applied to fuselage as per request from PIC.

Some airlines have instruction to use T2 or T4 in front of the engine inlet (cases such as MD-11, B727 or similiar) to prevent ice accumulation in that area. It could be ingested by engine during spool-up. Somewhat theoretical, but risk do exists.

Type 4 can also be put on the fuselage if requested, but I cannot see any reason for that - even very high snowfall usually does not build up significantly on top of the roof (even less if it has been sprayed with T1).

Good reasons given above to do proper de-icing on the fuselage. To have point of view for beancounters it usually takes about 100-200 litres of de-icing fluids to give the tube a good rinse, depending on your local contract just barely above 200-300 euros. Not too much for safety, what do you recon.

I do training for de-icers in northern europe and it is good to see pilots to recognize the risks too - it is easier for both parties if we play the same game :ok: