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Cirrus Jet (combined thread)

Well that’s the first POH I have ever seen which tells the pilot not to fly in bad wx

However that POH is not for the jet; it is for an SR22.

Administrator
Shoreham EGKA, United Kingdom

Comments on kathrynsreport (that just comments, but it’s all that we have) seems to emphase on pilot decision to takeoff although windshear of 20kn+ was advised.
Does any one know if windshear is one of the scenarii of the SF50 type rating? I’m curious that also SF50 does implement radar, how can a pilot decide to TO inside a red cell with thunder…

LFMD, France

greg_mp wrote:

I’m curious that also SF50 does implement radar, how can a pilot decide to TO inside a red cell with thunder…

You wouldn’t really use Radar on the ground – it gets turned on only when lining up on the runway, it is considered impolite to irradiate people on the ground with it…

However, the the SF50 also implements “Windows”, a technology that miraculously allows one to observer the weather conditions surrounding the aircraft, and “Radio”, which in this case allowed listening to the wind shear warning.

Unfortunately, “airmanship”, “common sense”, and “good judgement” are optional extras.

Biggin Hill

There is always windshear if there is wind

It’s just a question of how much.

20kt WS on takeoff is nothing. It is what you get if departing in say 20kt wind (say, straight down the runway). You see 40kt pretty soon. Assuming you depart into wind, you climb into increasing headwind, and the aircraft inertia (which acts along its vector, regardless of wind etc) gives you an impressive rate of climb. I once say +3000fpm in the TB20; the passenger was really impressed

20kt WS if landing would be harder, but you will know it from the reported wind, and add perhaps 10-20kt to Vref, and not choose to land on a 500m runway…

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Well that’s the first POH I have ever seen which tells the pilot not to fly in bad wx

However that POH is not for the jet; it is for an SR22.

It’s the same UI and physics is close although heavy jets are fragile to WS near the ground compared to light pistons

Peter wrote:

20kt WS on takeoff is nothing…20kt WS if landing would be harder

Maybe not an issue if you keep 1deg incidence and 1deg AoA in pistons? as long as you wait for it to be ready to liftoff by herself nothing can go wrong, any +WS after is a bonus

But in jets you go on +20deg incidence right after Vr which probably never factored any WS or wind changes, with such incidence +20deg AoA is not far away if the aircraft is still stuck in the ground for some reason, the pilot is flying on ASI > Vr and VSI>0 rather than his feeling or letting her liftoff by herself, if you fly jets in +20kts WS the same way as piston you may need 5km runway and new tires

For landing a similar story, one can afford to lose 30kts on IAS and freefall before go-around in microlight when it’s gusty between the trees, you have instantaneous power and WS feedback pass-through right on the spot to pilot head and teeth in SF50, flown on coupled ILS/LPV behind the screens on AT & AP with load of inertia and wing load, +20kts WS does not pass-through to pilot teeth, it has to be interpreted from performance data but the time the pilot figure it out and engine accelerate your are already in the turf !

Last Edited by Ibra at 31 Aug 14:16
Paris/Essex, France/UK, United Kingdom

Well, wind shear (as reported in wind shear warnings) is a SUDDEN increase or decrease in airspeed, we are not talking the normal change of wind speed and direction in the transition through the ground boundary layer. So a reported windshear of 20kt is not “nothing”.

And with thunderstorms in the vicinity, the direction is not driven by the general direction of wind, but can also be influenced by the storm cell; the most dangerous one is the “microburst” downdraft which can change the wind velocity typically from headwind (component) to tailwind (component) as you fly under the cloud.

With a cell above the airport, you can find a nice strong headwind turning into a tailwind just after lift-off.

Biggin Hill

Yes it’s not just wind gradient or stationary turbulence, it’s also the change of wind values (speed & direction) vs horizontal & lateral positions, the wind at the wind sock is not the wind you are rotating on takeoff or the wind you are flaring on landing, now if +/-20kts on IAS is a big deal?

This will matter a lot for heavy jet aircrafts flown “by the numbers” with load of mass & power inertia but some aircrafts may tolerate +/-20kts IAS as they do in the hands of very sloppy or less informed pilots

Last Edited by Ibra at 31 Aug 17:45
Paris/Essex, France/UK, United Kingdom
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