When flying a powered aircraft, sometimes you need to go land when you didn't expect to. The cause could be an emergency, such as a fire, bird strike on the propeller, engine problems, or a number of other things.
Or it could be a precautionary landing, where the aircraft is working fine but it would be prudent to get on the ground Real Soon Now. Examples include fuel shortages, or weather closing in on a VFR-only pilot.
Today's practice involved:
- Flying downwind, which is parallel to the runway but in the opposite direction,
- At circuit height, which is 1000' above airport elevation (AAE),
- With no conflicting traffic (since this is only a simulation, and therefore elective),
- Chopping the power, and gliding to the runway and a safe landing.
Somewhere on the downwind, usually opposite the threshold, we announce our intentions (just n case there is someone in the circuit), then chop the power to idle:
- Point the aircraft at the threshold - we have "no" engine, so it is not a good idea to fly further away from our friend, the runway,
- Get the airspeed to 73 knots, which is the best L/D speed for this aircraft. When flying at this speed we have the most range - if you fly any faster OR any slower, you won't go as far, and being able to fly (glide) further means you have more options for landing,
- Perform the Cause Check (this can be done while waiting for the airspeed to shed). Fuel pump on, mags both, fuel cutoff open, mixture rich, air alternate, temperature and pressure. Sometimes it can be as simple as descending from a great altitude but not moving the mixture from lean to rich, thus starving the engine for fuel - and correcting the problem means you again have an engine - nd no need for a forced landing,
- Communicate. In a true forced landing we're going for the runway threshold and have no options, and so it becomes everyone else's responsibility to stay out of our way - but so far we haven't told anyone that we're doing something non-standard. We've got the airplane doing the right things to make the runway, and we're going to be doing a lot of focused flying in the next while, so it's time to engage everyone else and get them out of our way, so we don't have to worry about them while we need to be worrying about us. When doing a simulated forced landing we announced our intentions on the radio on the downwind before even starting and make sure there are no conflicts - and if there are then we do the good citizen thing and just do a normal circuit and landing,
- Now it's time to get down, while managing the energy available so we don't end up short of the runway. Remember that the Eclipse is real slippery, and has an 11:1 glide ratio. We had 1000' of height, so we can glide 11,000'. Unfortunately, the runway is maybe 3,000' away.
- Time to get out full flaps (they cause lots of drag, and allow a steeper angle of descent without having to fly faster). We're flying at 73 knots, but the maximum full-flap flying speed is 78 knots. I'm trying to get down, which means I have lots of energy in the bank, which means I can safely fly at a non-perfect L/D speed... so I drop the speed to 70 knots to give a bit more protection against overspeeding the flaps,
- Still lots of energy, and much closer to the threshold, and so I kick in a forward slip. We're in a left-hand turn to align with the runway, so I use right rudder (which points the nose of the aircraft to the right, and away from the runway), and left aileron (which causes me to turn to the left towards the runway), and also use the elevator (stick forward/back) to keep my speed at 70kt. We're flying in a circle to line up with the runway centre line, but we're flying with the left wing noticeably down, and with the nose well right of our ground track. In effect, we're flying somewhat sideways and the whole left side of the aircraft is plowing a lot of air - and we're shedding altitude fast (when up in the practice area I could get a descent of well over 1000 feet per minute).
- When still comfortably higher than the glide slope and well sure of reaching the runway, I smoothly lose the forward slip by relaxing the right rudder (my leg is sore by this time) and bringing the stick to centre, and continue to manage the speed with the elevator. Now I am lined up with the runway and approaching the threshold, and it's time to get speed to 60 knots (which means I won't glide as far since it is further from the optimal 73 knots), and get stabilized for the landing. If still hot, or if there is a crosswind, I can put in a side slip.
- And land the plane normally.
So how'd I do on my three attempts?
First landing I nailed it. Great forward slip, smooth exit from the slip, good flare and I greased the landing a safe distance down the runway - you want to maintain a positive energy bank account at all times, for example, you could encounter sink just off the threshold. Touch&go and off to attempt #2,
On the second landing I got lazy - I took a looser circle to the threshold, my speed sometimes dropped to 60 knots (which meant I couldn't fly as far), and I didn't recognize my draining energy bank account as quickly as I should have, and didn't let out of the slip as soon as I should have. I was a bit low off the threshold and if I truly didn't have an engine then I probably could have stretched it out to the runway - but this is a simulation. I put in a touch of power, then chopped it and performed the touch&go. Off to attempt #3.Learning experiences from attempt 2:
- Don't perform a lazy circle - make a beeline to the runway.
- Speed management!
- Above all else make sure you make the runway. Lose the slip to get closer, and re-engage it when you're sure you have lots of energy int he bank.
- No configuration changes close to the ground. Ever. I did this right. If I was energy-shy at a good altitude then I would remove the flaps, and extend my gliding range. Shedding all that drag is useful if gliding into a headwind, or if the energy bank account is low. But by the time I figured out that I was tight on energy I was close to the ground, and any configuration change close to the ground is generally a Bad Thing. Removing flaps, for example, will first result in a loss of lift and an altitude drop as well as reduce drag - but by the time I could take advantage of the reduced drag I'm probably out of altitude. And so I used the engine to get me to the runway. In a true emergency you do what is required to get to the runway, since everything else is usually a worse outcome.
Forced Landings: 3 (two successful, one possible if it were a true emergency)
What I did well:
- Forward slips, especially the smooth exit
- Side slips
- Energy management (except attempt #2)
- Tracking without thinking - somehow I managed to "wear" the airplane to where I wanted it, without having to think about what specific control inputs were required,
- Speed management (except attempt #2)
- Self-diagnosis. I damn near interrogate the instructor on the details while climbing out and during the downwind - it's my style of learning, in that I just don't want to know what works, but why it works, and how it is connected to everything else, and did I make the right decisions.
- Not changing the aircraft's configuration when I was short of energy - even in a tight situation, safety first.
- Recognize when a shortfall in energy may occur, sooner, and then switch to a distance glide to ensure we make the runway
- I have to think before engaging a forward slipping turn.
- Keeping the rudder right to the floor in a forward slip.
- Gliding the aircraft right in, managing the energy so the safety buffer was always there.
- Telling my wife about flying a forward slip at 100' AGL (somehow she thinks it isn't normal to be flying sideway through the air).
Next lesson we'll add precautionary landings and forced landings off-airport, which involves landing site selection, managing energy, managing crosswinds, etc. Unfortunately, we cannot descend below 500 feet above ground level (AGL) for the off-airport practice.
After this lesson I was exhilarated.
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