X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [207.46.163.210] (HELO na01-bl2-obe.outbound.protection.outlook.com) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6644583 for lml@lancaironline.net; Wed, 18 Dec 2013 17:24:36 -0500 Received-SPF: pass receiver=logan.com; client-ip=207.46.163.210; envelope-from=rpastusek@htii.com Received: from BY2PR07MB550.namprd07.prod.outlook.com (10.141.217.145) by BY2PR07MB549.namprd07.prod.outlook.com (10.141.217.140) with Microsoft SMTP Server (TLS) id 15.0.842.7; Wed, 18 Dec 2013 22:23:37 +0000 Received: from BY2PR07MB550.namprd07.prod.outlook.com ([10.141.217.145]) by BY2PR07MB550.namprd07.prod.outlook.com ([10.141.217.145]) with mapi id 15.00.0842.003; Wed, 18 Dec 2013 22:23:37 +0000 From: Robert R Pastusek To: Lancair Mailing List Subject: RE: [LML] 4P landing on snow Thread-Topic: [LML] 4P landing on snow Thread-Index: AQHO/DHuxJAE50I0l0uJk4bt/CN78ppaeMkw Date: Wed, 18 Dec 2013 22:23:35 +0000 Message-ID: <968127cb846b480d92f4bfcf6542ed0e@BY2PR07MB550.namprd07.prod.outlook.com> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [108.28.164.93] x-forefront-prvs: 0064B3273C x-forefront-antispam-report: SFV:NSPM;SFS:(10019001)(199002)(57704003)(24454002)(189002)(53234003)(90146001)(81542001)(47446002)(79102001)(63696002)(56816005)(74502001)(65816001)(74706001)(83072002)(87936001)(81342001)(87266001)(2656002)(66066001)(76576001)(76796001)(69226001)(76482001)(74662001)(80976001)(76786001)(74366001)(16236675002)(19300405004)(59766001)(56776001)(85852003)(53806001)(31966008)(74316001)(83322001)(19580405001)(19580395003)(85306002)(54316002)(4396001)(50986001)(33646001)(49866001)(47976001)(15975445006)(80022001)(54356001)(81816001)(51856001)(74876001)(46102001)(77982001)(47736001)(15202345003)(81686001)(24736002);DIR:OUT;SFP:1102;SCL:1;SRVR:BY2PR07MB549;H:BY2PR07MB550.namprd07.prod.outlook.com;CLIP:108.28.164.93;FPR:;RD:InfoNoRecords;A:1;MX:1;LANG:en; Content-Type: multipart/alternative; boundary="_000_968127cb846b480d92f4bfcf6542ed0eBY2PR07MB550namprd07pro_" MIME-Version: 1.0 X-OriginatorOrg: htii.com --_000_968127cb846b480d92f4bfcf6542ed0eBY2PR07MB550namprd07pro_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Ralf wrote: We have winter in Ohio now and most of our runways are plowed but still do = have compacted patchy snow on it. Is there anybody on the list who can give me some advice on departing and l= anding a 4P on snow? How much runway do I need if braking action is very small? Does it behave l= ike normal or is it much different on snow? How do you hold it straight at = the start when the rudder is not working yet? Any input is appreciated. Ralf, I am by no means an authority, and I have only operated my IV-P on icy/snow= y runways a few times, but can give you some tips/considerations from flyin= g small airplanes (and F-4's) in Alaska for several years... First of all, there are some bright sunny winter days that look good for fl= ying that just are not suitable. Icy or patchy runways/taxiways combined wi= th strong winds and/or short runways are my best examples. The IV-P will "w= eather vane" with the best of small airplanes if all the wheels don't have = a good grip on the surface, and when it starts, abrupt controls to "regain = the straight and narrow" can make it much worse...very quickly. So the first tip: GENTLE on the controls...all of them...starting with the = brakes, and especially with the power on takeoff. You should be able to eas= ily advance the power to takeoff without touching the brakes. Takes just a = bit more runway to get to full power with the slow throttle push, but with = winter temps, your takeoff roll is probably shorter than summer anyway. Aga= in, crosswinds are more treacherous than when operating on a dry surface. = Your crosswind limits should be SIGNIFICANTLY reduced...and it's not just a= takeoff/landing consideration. Maneuvering the airplane on the ground can = also be an issue. So there is also a rather low total wind that's acceptabl= e if the taxi/takeoff surfaces are slippery/patchy. Another tip: Be prepare= d to shut down the engine (completely and quickly) with the magneto switch = if you get into trouble during taxi. In the F-4, we had very detailed stopping distance charts for various runwa= y braking coefficients (which were measured and broadcast by the tower), bu= t neither are readily available for most GA operations. You can, however do= some testing on your own before venturing out on the ice. Try landing and = rolling out, using only aero braking, the next time you're out flying on dr= y runway, to see how much distance it will take. In my experience, the airp= lane won't ever stop rolling on a hard surface without the brakes...unless = you shut down the engine after landing. So give it a try, then try some ver= y light braking after slowing to 50 kts or less. This somewhat replicates t= he slight wheel drag that a small amount of snow will provide, and will giv= e you some idea of runway required. 5,000' is probably the minimum I'd even= consider for an icy/patchy runway; 7,000' should be sufficient if you land= at the approach end (L not all of our pilots do this!) with the speed at 1= .2-1.3 stall--remembering that it varies with weight. Remember that the ene= rgy needed to stop is a function of the square of the touchdown velocity. F= ive knots makes a big difference! You mentioned landing/taking off on snow. I'd be really careful there. I've= not thought of "how much snow" I'd try to fly with, but it's probably half= an inch or less accumulation on the operating surfaces. Several considerat= ions here; first being that with snow on the taxi surface, you can't see wh= at you're taxiing over. Some serious risks therein. Second, if you try to b= rake with a snow accumulation on the surface, it's likely the wheel will lo= ck up and pile snow in front of it--quickly. Depending on conditions, it ma= y not start turning and "jump over" the snow berm when you release the brak= e; you have just locked up one wheel, for all practical purposes. Did I men= tion "gentle on the controls"...should have also said SLOW and steady. This is by no means a complete discussion/consideration. I'm sure others ha= ve LOTS more experience with Lancairs, and can offer better/more advice. I'= ve put too much time and money into my airplane to want to just go out and = experiment with adverse conditions--anytime. I'm not saying that I won't go= at all; just that my "minimums" change. The fact that you are thinking ahe= ad about these things is probably your best defense--and preparation...just= be careful! My two cents; views of others? Bob --_000_968127cb846b480d92f4bfcf6542ed0eBY2PR07MB550namprd07pro_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Ralf wrote:

 

We have winter in Ohio now and most of our runways a= re plowed but still do have compacted patchy snow on it.

 

Is there anybody on the list who can give me some ad= vice on departing and landing a 4P on snow?

 

How much runway do I need if braking action is very = small? Does it behave like normal or is it much different on snow? How do y= ou hold it straight at the start when the rudder is not working yet?

 

Any input is appreciated.

 

 

Ralf,

I am by no means an authority, and I have only operated my IV-P= on icy/snowy runways a few times, but can give you some tips/considerations from flying small airplanes (and F-4’s)= in Alaska for several years…

 

First of all, there are some bright sunny winter days that look= good for flying that just are not suitable. Icy or patchy runways/taxiways combined with strong winds and/or short runways= are my best examples. The IV-P will “weather vane” with the be= st of small airplanes if all the wheels don’t have a good grip on the= surface, and when it starts, abrupt controls to “regain the straight and narrow” can make it much worse…very quickly.<= span style=3D"mso-spacerun:yes"> 

 

So the first tip: GENTLE on the controls…all of them̷= 0;starting with the brakes, and especially with the power on takeoff. You should be able to easily advance the power to takeoff with= out touching the brakes. Takes just a bit more runway to get to full power = with the slow throttle push, but with winter temps, your takeoff roll is pr= obably shorter than summer anyway. Again, crosswinds are more treacherous than when operating on a dry surfac= e.  Your crosswind limits should be SIGNIFICANTLY reduced…and it&#= 8217;s not just a takeoff/landing consideration. Maneuvering the airplane o= n the ground can also be an issue. So there is also a rather low total wind= that’s acceptable if the taxi/takeoff surfaces are slippery/patchy. Another tip: Be prepared to shut down the engine (com= pletely and quickly) with the magneto switch if you get into trouble during= taxi.

 

In the F-4, we had very detailed stopping distance charts for v= arious runway braking coefficients (which were measured and broadcast by the tower), but neither are readily available fo= r most GA operations. You can, however do some testing on your own before v= enturing out on the ice. Try landing and rolling out, using only aero braki= ng, the next time you’re out flying on dry runway, to see how much distance it will take. In my experience, th= e airplane won’t ever stop rolling on a hard surface without the brak= es…unless you shut down the engine after landing. So give it a try, t= hen try some very light braking after slowing to 50 kts or less. This somewhat replicates = the slight wheel drag that a small amount of snow will provide, and will gi= ve you some idea of runway required. 5,000’ is probably the minimum I= ’d even consider for an icy/patchy runway; 7,000’ should be sufficient if you land at the approach end (= L= not all of our pilots do this!) with the speed at 1.2-1.3 stall--rememberi= ng that it varies with weight. Remember that the energy needed to stop is a= function of the square of the touchdown velocity. Five knots makes a big d= ifference!

 

You mentioned landing/taking off on snow. I’d be really c= areful there. I’ve not thought of “how much snow” I’= ;d try to fly with, but it’s probably half an inch or less accumulation= on the operating surfaces. Several considerations here; first being that w= ith snow on the taxi surface, you can’t see what you’re taxiing= over. Some serious risks therein. Second, if you try to brake with a snow accumulation on the= surface, it’s likely the wheel will lock up and pile snow in front o= f it--quickly. Depending on conditions, it may not start turning and “= ;jump over” the snow berm when you release the brake; you have just locked up one wheel, for all practical purposes. Did = I mention “gentle on the controls”…should have also said = SLOW and steady.

 

This is by no means a complete discussion/consideration. I̵= 7;m sure others have LOTS more experience with Lancairs, and can offer better/more advice. I= ’ve put too much time and money into my airplane to want to just go o= ut and experiment with adverse conditions--anytime. I’m not saying th= at I won’t go at all; just that my “minimums” change. The fact that you are thinking ahead about these things is probabl= y your best defense--and preparation…just be careful!

 

My two cents; views of others?

 

Bob

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