Fri Sep 14, 2018 6:56 pm
You asked about approach speed, and this is what UK glider pilots are taught :
1. Nil wind approach speed is 1.3 x Vs. Add half the estimated headwind for best penetration, ie to achieve best distance over the ground, and to allow for gusts. If its very gusty, more speed won't hurt if you'll still stop within the field.
2. In a strong wind, say 15kt+, you might encounter a strong wind gradient. This is where the wind speed drops appreciably as you descend. The problem is that it takes time for the aircraft to overcome inertia, ie to increase its speed over the ground. So I've commonly seen 10kt or more wiped from my airspeed, which takes me closer to the stall than I want! In a glider the remedy is to lower the nose markedly, and it will pick up speed in plenty of time if you don't delay. In a draggy engine-out aircraft the ground might arrive first, so I'd guess you increase your approach speed early on to give you a margin if this happens. I get the impression that in power the wind gradient is less noticeable, because the propellor is pulling you through the air, so this one could catch you out.
3. If there's a crosswind, curl over from trees or even a hedge can be a nasty surprise in the last 50 ft or so, and a reserve of airspeed helps to give enough control authority to cope. It generally stops as you round out. Landing towards the far side of the field helps.
You probably won't have the problem that gliders have, which is that the aircraft will float until you've bled off your airspeed above the stall (or more accurately, you're so draggy that this won't take long). So you might be able to give yourself a higher margin over Vs than a glider can risk.
However, don't assume this all applies to an engine out aircraft because I don't know where there might be differences. It might be worth talking these points through with an appropriate instructor (one who focuses on stick and rudder flying, rather than procedural flying, as there's no manual for your selected field so you have to improvise).