Pressurisation system can seem daunting and hard to get your head around at times (and it certainly was for me), but it’s really quite simple. My simple trick is I set the controller to 5000ft cabin alt. That way, when I take off, the cabin stays unpressurised until I reach 5000ft, then the system will keep that cabin altitude until it reaches it’s max differential, wherever that altitude might be. In the case of the Cessna, at 20000ft, it will probably have around a 10000ft cabin, maybe a bit more. This way, I don’t have to mess with setting landing altitudes etc and won’t forget (since it’s very rare I land airports with elevations above 5000ft). If I do, I have to remember to set it to field elevation + 1000ft on descent. Worst case scenario, even if you forget, when the squat switches on the plane depress after landing, the cabin will depressurize. If you left controller at 5000ft and then landed at a 6000ft elevation, it wouldn’t be a big thing. Barely feel a pop.
@Mooney_Driver I have a friend here who owns a P210 (not sure which model) if you have any specific questions let me know. I have some hours in 210s (not pressurized) and love them. Very stable platform. Most (prob almost all) have the gear-door removal mod which simplifies things a lot. I have flown one with the old-style gear doors and that’s a handful !
Thanks guys. I’ll let the person who asked me know and maybe point him to this thread.
So basically it is a relatively easy to fly but complex to maintain and operate airframe.
… but complex to maintain and operate airframe.
“Complex to operate” is always relative. It’s not a Cessna 172 where you push in the throttle fully upon takeoff, leave it that way during climb, and maintain some “best” airspeed until you either have reached your desired altitude or it will just stop climbing. And upon descent pull it to idle and leave it that way until touchdown. Do that with a 210 (or any aeroplane with a powerful air cooled engine inside a tight cowling) and your engine will last less than 200 hours…
What you need to do instead is set climb power according to the book. Then watch your temperatures all the way up and adjust your speed accordingly. When the engine starts getting hot you need to lower the nose and increase speed for more cooling airflow. Don’t climb higher than necessary. The higher you go, the longer the climb will take and the hotter the engine will get. (The same with pressurised twin Cessnas. I have over 1000 hours on them but not more than maybe 20 hours above FL200. And never experienced a cracked cylinder).
But the most important thing is to avoid rapid engine cooling. The only time during an entire flight when the power needs to be at idle is over the numbers prior touchdown. During cruise and descent the power needs to be on all the time. This requires very careful descent planning. A good figure is to reduce manifold pressure by one inch per minute which will take about 15 minutes. In order not to bust the red line speed during a powered descent the resulting ROD can be fairly low, maybe only 500ft/min, so descent really must begin early. This is not something a typical low-hour PPL holder was ever trained to do.
And after landing never forget to observe the 2 minute cooling period for the turbocharger…
Thanks, this is good information.
Cool down period, I recall it well from the Senecas.
Actually, unless you drag in at very high power, at the end of the landing roll, the turbo and related components are at the lowest temp they are going to get before switching off; this so called cooling-down period is in reality heating up because of lack of airflow. This was explained to us, with actual data, during the APS seminar.
It depends on how you have to taxi in and for how long. On a level paved surface idle power should be sufficient for taxiing, so your taxi time can count as the cooling period and you can shut the engine down when reaching your parking position. But when substantial power is required for taxiing (eg. on grass or uphill) then some extra cooling time will certainly not hurt.
dirkdj wrote:
Actually, unless you drag in at very high power, at the end of the landing roll, the turbo and related components are at the lowest temp they are going to get before switching off; this so called cooling-down period is in reality heating up because of lack of airflow.
This can work but doesn’t have to. It depends strongly on the airport.
The primary bit is that the engine(s) have to be running at low power for at least 2 minutes before shut down. I’ve seen people land and just turn out of the runway onto their parking turf and smashing the mixtures closed. Not good.
The turbine shaft is oil cooled – the efficiency of which depends on airflow & oil flow (volume & pressure). Low airflow & low oil flow in conjunction can’t be that good I would think.
The primary bit is that the engine(s) have to be running at low power for at least 2 minutes before shut down. I’ve seen people land and just turn out of the runway onto their parking turf and smashing the mixtures closed. Not good.
But on approach the engines are running at low power for many minutes, and taxiing is done low power too (except for the guys who are always on the brakes). Standing still with the engines running only lets the oil temperature go up.
