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Airframe icing today.. poor landing. coincedence?

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Airframe icing today.. poor landing. coincedence?

Old 15th Mar 2015, 22:56
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Airframe icing today.. poor landing. coincedence?

Bit of a strange one this. We were flying today from down south back up north, C 172 and I was flying in IMC for a large part of the journey (1.2 hr flying ish). So the forecast said there was potential icing and it seemed it could have gone up to 10,000ft from what my copilot read (FI, 6000+ hours on small and big planes). We were at around 4,000ft-5000ft and this was because routing necessitated it.

So we kept a close eye on it and maybe 45 minutes in some ice was spotted under the wings and from there it built up quite fast, not badly on the leading edge but the strut was quite affected and various other parts (pitot, steps etc ) Pitot heater worked however. So we commenced descent as climbing out of it was not an option. Windshield was heavily iced over at this stage.

Descent was uneventful and we popped out of the muck at around 1800 feet, ice was visibly melting.

Runway came into site soon after and I put it down (maybe 3 minutes since out of cloud).
The plane seemed to be a bit wooly on landing and I ended up hooning in a bit quick and where I was expecting it to hold the flare it seemed to drop (no stall warner) and a bounce and then I caught it on the next bounce.

My question, is it possible that ice on the airframe somewhere could have contributed or I just screwed up?? I am puzzled about it because normal landings are nice and predictable and I haven't done a bounce for some months!!! thanks

Last edited by anderow; 15th Mar 2015 at 23:17.
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Old 15th Mar 2015, 23:07
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Tailplane icing.
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Old 15th Mar 2015, 23:20
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I did wonder about this possibility. Any other thoughts, anyone?
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Old 15th Mar 2015, 23:21
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Agree with Cusco.

Also pro rata if you've got a bit of ice on the wings there will be a lot more on the tailplane where it can build up more quickly. Also as the tailplane is thinner you don't need much for it to have a significant effect aerodynamically.
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Old 15th Mar 2015, 23:21
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Anderow

I can remember training for an IR in a PA28 We were in an airway at FL80 in solid IMC when the instructor told me to hold my altitude.
I pointed out that I had max power and sped was back to 75 KTS and we were going down.
He quickly asked ATC for a lower level and we were cleared to no lower than FL60
we sailed down through FL60 and only stopped at 4000 feet with terrain at 2300 feet below
had the icing level been lower God knows ?
don't mess with icing in a non deice anti ice capable aircraft.
If you do carry extra speed to a normal approach and landing as your stall will be higher and although the ice may melt off in certain areas you may have quite a buildup on other areas of the airframe

Pace
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Old 15th Mar 2015, 23:47
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dear OP:

what does "HOONING" mean? and "Whooly"?

I thought you british folk didn't like ice with your drinks, so why would you like it on your airfoil?
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Old 16th Mar 2015, 00:09
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Anderow

Did you follow the procedures in the C 172 POH emergency checklist for "inadvertent icing encounter ", particularly the direction to use zero flap ?
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Old 16th Mar 2015, 00:18
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Did you follow the procedures in the C 172 POH emergency checklist for "inadvertent icing encounter ", particularly the direction to use zero flap ?
BPF, good point!
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Old 16th Mar 2015, 02:16
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The accident record shows 2 types of icing accidents.
  1. FIT usually uncontrolled when unable to stay airborne
  2. Stall in late approach - - not uncommon.
Once you have the good fortune to emerge still flying, you may want to find a long runway that will accommodate an extra 30 kt on approach.
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Old 16th Mar 2015, 08:11
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Gatwick ATIS yesterday

There was plenty of icing around yesterday. After flying around in generally ‘claggy’ conditions I didn’t actually pick any up, but Gatwick ATIS was giving ‘moderate icing between 1,000’ and FL 070’.
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Old 16th Mar 2015, 08:26
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Old C172 wisdom - "when ice on dick, you feel sick" - did the OP extend flaps as usual, or use emergency checklist to land with zero flaps? With ice on the tail you are usually shifted back in the envelope and when heavy anyways could stall the machine by that (would explain bouncing as well, as w&b would get you wrong on landing).
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Old 16th Mar 2015, 08:55
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Just a word of warning as its something which is close to my heart. A very close friend and Ferry pilot was killed ferrying a 172 in Canada which iced up.
He didn't stop going down till impacting a shallow river in Canada.

Do not fly in conditions where there maybe icing unless your aircraft is approved for ice and even then use that capability to get out of it.

Most certainly do not go into icing conditions unless you know by going down to lower levels you can remove it and that those levels are way above terrain.
It is not something to mess with

Pace
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Old 16th Mar 2015, 09:40
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The form 214 for the 15th March showed a freezing level at 2000'. Normally they are pretty accurate. I took off at 15:00 with a surface temperature of +7 and found ice at 2 500' that went fairly well up to 18 000'


Form 214 is a good thing to keep in your armoury, I certainly would not have wanted to go flying above 2 000' in an aircraft without anti-ice kit yesterday.


SND
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Old 16th Mar 2015, 09:44
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A fair while ago I flew a 737 into BHX in icing conditions. We spent as little time as possible going through the bad icing layer but you could see the build up on the wipers, etc.

I added 10kts to the final approach speed and even with that, flaring was a real effort and it sat down with a thump. This is in an aircraft with copious amounts of hot bleed air anti-/de-icing on the engines and leading edges that is certified for flight into known icing conditions. Power settings on the approach were a fair bit above normal too.

I get the feeling that a light aircraft would have just crashed as it was below freezing at ground level, so no chance of it melting.

Don’t go there!
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Old 16th Mar 2015, 10:04
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With ice on the wings it is very normal for stall speed to go up, stall characteristics to become worse, and overall lift v drag to become worse.

There have been several crashes of Jets in the states where the pilots have not carried the recommended extra airspeed and have stalled on approach (whilst on the dry wing recommended approach speed).

I would have thought rather than tailplane icing it was just the natural degradation of wing performance, flying the approach at close to your undocumented stall speed and then stalling it in rather than flaring. A good thing it happened a couple of feet above the ground rather than 100 feet above the ground.
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Old 16th Mar 2015, 10:22
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Thanks guys. Some excellent input here from much more knowledgeable folks.

Yes, this was an unplanned icing encounter and I am fully aware of the 172 non icing capability, even more so now.
There was 4 on board so we were heavy but within limits.


Cloud was patchy for some of the distance and hence IMC/VFR on and off so icing was not an issue initially, it was only when the clag got heavier that it was noticed, and it came quickly, though we knew we did have the height above terrain and melting point below to let it melt off but it wasn't considered an emergency as we were commencing descent very soon after that point so would be in warmer air. I think given any longer in those conditions and we would have descended regardless.


However after landing I noticed melted ice (significant amount) that had fallen off the plane and that is when I realised it may have been more than we could see.

I didn't get time to use the cessna inadvertent icing checklist (truth be told I didn't think of it) but I used only 20 degree of flap and around 75-80 knots on final. It was at the slower end of the flight envelope that thing's seemed to fly differently..!!

Last edited by anderow; 16th Mar 2015 at 11:05.
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Old 16th Mar 2015, 11:24
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Yup that's what happens when you get covered in ice. The struts would have been a clue, it's likely the wings would have been worse. I fly a low wing so it's relatively easy to see and definitely not to be underestimated.
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Old 16th Mar 2015, 17:51
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The point about using flaps up as recommended by Cessna is that if you have ice on the tail plane and you lower flap on the approach the tail plane may stall resulting in loss of control in pitch and you usually lower flap when relatively near the ground.

Over the years quite a few aircraft have come to grief this way. If you're quick you might getaway with it if you retract flaps!
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Old 16th Mar 2015, 18:10
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I think in these circumstances I would have stayed flying in the warmer air for longer than three mins and given it more of a chance to melt, though if unsure if you are in air that will melt the ice than do as suggested with extra speed and recommended configuration on the approach. Another thing to consider if you have enough height is a low speed handling check, but doing this too low is not advisable.
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Old 16th Mar 2015, 21:33
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I have to confess that I'm shocked that the 6000 hour FI with all that experience didn't have any contribution to make towards making this a safer flight.

The holes in the cheese were lining up and maybe you got lucky, but there were plenty of options to reduce the risks in the trip you describe. Most of which have been covered by other posts.

F214, and associated pre-flight planning - the route forced you to that level. Consider choosing a route that avoids icing, or at the very least affords you the option to avoid forecast icing conditions.

Four up in a C172 is tending towards the tricky end from a W&B perspective which may not help.

Once icing is recognised flying a non-FIKI approved aeroplane, you are now effectively flying an untested aeroplane. In the case of inadvertent entry into icing conditions, the POH calls for leaving by the safest and most expeditious route. Often this requires a descent to warmer air. In some cases the aircraft forces this because its performance is so degraded that it can no longer maintain altitude.

Use of flaps is often precluded in the case of icing. Your wing is no longer the aerofoil it was intended to be, and its behaviour is no longer certain. Changing its behaviour further by extending flaps is not a good idea, particularly when that same ice might prevent a retraction of the flaps. Knowing the POH in this case might have been useful.

Recognising that the tailplane will undoubtably also have been affected should have raised awareness that "feel" in pitch, trim management and speed control may also be affected.

The recommendation to wait further before landing to allow more ice to melt is good, if and only if the conditions allow it. If there was space, time, and fuel permitting it then handling checks and reduced icing could have helped.

Actually, it's great that you've posted this. I am sure that there are lots of people who hadn't thought about the symptoms, consequences and mitigations of this kind of risk. I am also sure that there are wiser people than I who can further add to and refine the advice regarding this scenario.
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