Flaps 10 glide during engine failure

[shumway76]

When you have an engine failure on single engine aircraft, do you use flaps 10 (for C172, so generally, do you select lift flaps) as soon as possible, or do you initially glide with flaps up?

What are the pros & cons of using lift flaps early during an engine failure?

[Big Pistons Forever]

The POH for the C 172 is quite specific on this question. It says that best glide speed (between 65 and 68 kts depending on the model) should be established as quickly as possible and the "Maximum Glide" chart specifies Flaps Up.

[Pilot DAR]

The right answer is to fly as the flight manual states. I expect that it specifies a flaps up glide. When your glide transitions from a glide for distance to the approach for landing, obviously some, hopefully all flaps will be extended.

Early extension of flaps will increase lift, which you do not need ("cause you got no thrust"), and will increase drag, which you really don't want then. Consider that increased drag will increase your descent angle. That might be what you want, but be careful what you ask for, you might get it. Remember that chances of survival are inversely proportional to angle of arrival. When you develop that steep descent angle, you'll want to convert it into a very shallow one before landing. This requires energy, which you do not have from the engine, so its you inertia only. With a lot of drag that goes away fast.

When I do familiarizing flying with owners in their STOL modified aircraft I would demonstrate, and train not to glide at speeds slower, or with more drag, than the flight manual states. You can do it, but slower means less inertia, and when you go to flare, there;s nothing left, and you stall and drop in unable to arrest your rate of descent.

You'll find many cases where flight can be accomplished at slower speeds or different configurations than the flight manual states. The plane might do it, but you may have unwittingly given up a reserve of safety (inertia) which did not even think about.

Yes, safely learn and understand, but ultimately you'll find the flight manual way is the best way - I've done a lot of flight testing, and that's what I have found....

[Old Fella]

Clean or Flaps

Extending Flap does a number of things. The camber of the wing is increased and thus more lift is produced for a given airspeed. Adversely, more drag is produced also. The aeroplane will have a better Lift/Drag ratio with the flaps retracted and when flown at the best glide speed will maximise the glide distance. Flying faster or slower than Best L/D Speed will reduce the glide distance. Flaps are best left up until a landing is assured.

[A and C]

Paint yourself into a corner

Selecting flap before landing is assured is throwing away performance, as said above the best lift/drag option is flap up at the PoH speed for the aircraft you are flying.

You can always get rid of energy with more drag but you can never get it back !

[Cows getting bigger]

This whole 'don't select until landing assured' discussion gets to me. Let me explain using the ubiquitous 172/152/PA28 with two examples.

Firstly a powered approach (I'll not get into the merits of such an approach, let's just take it as read that people fly these). If an aircraft is set up on a powered approach and at a sensible approach speed the landing is never assured. Dropping flap at 300ft or whatever is only going to forshortened the landing point. Agreed, you could drop the last stage 'over the fence' to drag off a few knots but do we really wish to reconfigure at this point?

Similar scenario but a glide approach. In this scenario the flaps are acting as your engine - controlling angle of descent. If your landing is 'assured' with two stages and you then drop the last stage (drag?) your landing s still assured but not at the same location. Again you will drag the landing point closer to you. This is why most sensible instructors teach that a glide should be aimed towards the far end of the landing area and pilots should adjust this point with the application of flap.

So, in summary, the 'landing assured' phrase needs to be understood in its entirety. Drop flap and do nothing else with the aircraft and you have moved your landing point. Your landing is only assured if you understand this and plan your approach accordingly.

[riseagainst]

I do not use flap until I'm certain that I will make it into the field and want to move my aim point closer. Lowering flap will spoil your lift to drag ratio, which I certaintly would not want to be doing until I am certain I will make it into the field.. Same as when I'm flying a glider ill fly a profile and only bring the spoilers out to move the aim point closer. I certainty would rather be slightly above profile than below.

[RatherBeFlying]

Keep the flaps up until over your chosen field. If you have tons of extra height, expend it in mini circuits while inspecting the field and approaches.

If there is any wind, downwind at slightly less than best glide speed gives you more choices and the option of doing a 180 into whatever looks acceptable.

Remember that a good approach to a poor field is much better than a poor approach to a good field.

Question: do you know how much altitude you will lose in a power off 360?

Once over the field, minimum sink speed is more appropriate than best glide as it gives you more think time. But as a glider pilot, I sometimes spend over half an hour "inspecting" a field before it turns out either that I have to land there or I find a thermal that gets me away.

For base and final, go back to at least approach speed and use flaps.

A good exercise is power off approach from the circuit. Bring the instructor along the first few times as he will remind you to have enough speed to flare with full flaps.

[Heston]

"Landing assured"? Oh its definitely assured if the engine's stopped

[Big Pistons Forever]

Originally Posted by RatherBeFlying

Remember that a good approach to a poor field is much better than a poor approach to a good field.

Excellent advice. When the engine stops the insurance company just became the proud owner of the aircraft. What the airplane looks like when it comes to a stop is immaterial, the only consideration is the health of the people in it.

The best way to ensure a successful outcome is to make sure the aircraft contacts a more or less level surface in a level attitude. Too fast is always better than too slow on the approach as you can always smash the aircraft into the ground if you have to. Too slow usually means coming up short and hitting something in the air and at flying speed .

Finally remember 80% of engine failures are caused by the actions or inactions of the pilot, so the best way to deal with an engine failure is to not let it fail in the first place.

[thing]

I know I've banged on about this before but all powered pilots should go solo on a glider first. It would take all the fear out of a forced landing, every landing in a glider is power off, you get one go and that's it. You don't read about glider pilots ballsing up a field landing.

Edit: I know the speeds and glide angles are different etc etc but the principle is the same.

[Big Pistons Forever]

Originally Posted by thing

I know I've banged on about this before but all powered pilots should go solo on a glider first. It would take all the fear out of a forced landing, every landing in a glider is power off, you get one go and that's it. You don't read about glider pilots ballsing up a field landing.

Edit: I know the speeds and glide angles are different etc etc but the principle is the same.

I have to say I disagree. I have taught 3 PPL's who started training with a glider license, albeit none with a lot of glider time. The basic stick and rudder skills certainly benefited from the glider time but I was surprised that all 3 took a bit of time picking up the PFL exercise. They all commented that they had so much more time to set up the approach in the glider and the fact that the spoilers could be treated like a pseudo "throttle" made the whole thing much easier in the glider. They are also programmed to always try to find a landing spot that will not damage the aircraft, a potentially lethal reflex in a powered aircraft that has suffered an engine failure.

In any case you are much more likely to experience a partial engine failure which will more than likely still allow you to maintain altitude, than a complete failure. I think flight training does pilots a huge dis service by emphasizing what is in the real world the statistically most unlikely possible scenario, a sudden and total loss of power with no warning.

[thing]

Can't argue with your views BPF, you're vastly more experienced than me but I can only speak for myself when I say that I never had any trouble with PFL's and I can't say that the thought of a donk failure bothers me too much. Of course I'd rather not have one but I would hope I would be fairly comfortable if I did have one.

I always fly like I'm expecting one at any rate, so I always keep a weather eye out for a landing spot and never fly over big swathes of city type area.

[RatherBeFlying]

I have to agree with BPF. Field selection and circuit management is a whole bunch easier coming down at 120 fpm than at 800 fpm.

And, glider pilots can and do have outlanding accidents, sometimes fatal.

You can get your glider license without ever having done an outlanding -- or talking to ATC . In fact the Bronze badge, which most clubs require before turning you loose for your 50 km cross-country is a post license exercise.

So it does not surprise me that BPF's licensed glider pilots required more teaching for PFLs. A PFL requires a lot to be done in a short time while outlandings are usually leisurely affairs.

[BackPacker]

You can get your glider license without ever having done an outlanding -- or talking to ATC . In fact the Bronze badge, which most clubs require before turning you loose for your 50 km cross-country is a post license exercise.

That's a bit of a sweeping statement. The requirements for glider licenses are somehow not standardized by ICAO (or nobody follows the ICAO recommendation, I don't know).

In the UK, AFAIK, the BGA *exclusively* uses the FAI badge system. They never issue you with a formal license.

In the Netherlands, there is a Glider Pilots License (which I have) which indeed can be done within 5 km of the field, and without any radio usage whatsoever. Only once you have the GPL will you start your x-country training.

EASA is going to change all this though (somewhere in 2014 I believe). There is going to be a formal EU-wide accepted Glider Pilots License, and this license will include x-country experience. From memory, the experience requirement is a 50 km solo flight or a 100 km dual flight.

Canada, US, Australia may all be different. I have no idea.

[India Four Two]

Canada, US, Australia may all be different. I have no idea.

Canada - 15 hours ground school, 60% on TC glider exam, 6 hours glider training under supervision of a Glider Instructor, including a minimum of 1 hour dual and 2 hours solo (including 20 take-offs and landings) and pass a skills test.

No requirement for cross-country or off-field landings.

Of course, all ab-initios take much longer than the minimum hours.

[Jim59]

The same European legislation that created the EASA PPL and LAPL(A) also created the LAPL(Sailplane) and Sailplane Pilots Licence (SPL). These licences all became available on the same date in 2012. However, there is a derogation in force which allows until 7th April 2015 for the UK to complete the conversion. Until then a licence is not required in UK airspace.

The training for the LAPL(S) and SPL is identical - as are the examinations. The requirements are:

• 10 hours of dual instruction.
• 2 hours of supervised solo.
• 45 launches and landings (their words not mine!)
• 1 solo cross country of 50 km or a dual cross country of 100 km.
• Pass the theoretical exams.
• Pass a flying skills test.

All instruction by an EASA FI and the examinations and skills test by an EASA FE. Same basic rules as for the PPL.

[BackPacker]

Yep, that's the one. To add, the only real difference between the LAPL(S) and SPL is the medical. SPL requires a class II, just like a PPL, where the LAPL(S) medical requirements are more at the NPPL/LAPL(A) level.

[thing]

I haven't kept up to speed with the EASA glider stuff. I have a silver 'c', would it just be a case of sending off the for the new license jobby?

Edit: and a class II medical.

[BackPacker]

Thing, I just checked the BGA website. Two things.

If you have at least bronze plus an x-country endorsement the BGA office apparently will issue you an ICAO compliant license right now. Or at least some paperwork saying you meet the ICAO requirements, or something like that. This is needed in case you go gliding in a country that does require a license.

Further, there is an FAQ on future licensing that is fairly vague at this time, but promises that everything will be sorted in the near future, including the process to obtain the license.

EASA Licensing