Full Flaps AFTER Landing

Flying Pig · February 13, 2009, 07:14:26 PM

I fly a Cessna Turbo Stationair on a daily basis. The plane I fly flies at almost gross weight and has a significant amount of equipment in the rear. In the 206 the nose becomes very heavy on landing so I rarely land with more than 10 degrees of flaps. Sometimes 20 degrees. I have no problems at all landing on some of the smallest and shortest strips with 20 degrees. I fly with about $500k worth of surveillance equipment so extremely graceful landings are a must.

My question, I discovered that after landing with 10 or 20 degrees, after my nose wheel is on the ground, I can then lower my flaps to full down. With full flaps out acting as big sails, the plane will slow and stop considerably without me ever touching the brakes. Any potential issues with this technique? Most 206 pilots I know really like to avoid landing with full flaps. Me included.

Trung Si Ma · February 13, 2009, 07:45:03 PM

I don't have any 206 time, but was taught to get rid of the flaps on a Birddog after landing to keep myself planted. I also know that on my 172 10 degrees of flaps are used for short field takeoffs so either all of them or none of them does seem to make sense.

Flying Pig · February 13, 2009, 08:15:39 PM

After I land, I immediately retract my flaps. However, beyond 20 degrees, which is the case for going ful flaps, you are not longer increasing the lift. I have been doing it and havnt had any negative results. With 20 degrees, I land very gingerly and then lower to full and come to an abrupt slow down just by the drag and resistance caused by full flaps. Hmmmmm.....Im trying to see if there are any negatives?

bosshawk · February 13, 2009, 08:30:08 PM

Rob: the one issue that I could see would occur if you suddenly had to go around. Then, full flaps will cause a bad pitch issue until you can retract them. I admit that they act as good speed brakes, but in most cases you shouldn't need that much braking action. Your agency can afford brake pads, so don't be too soft on them.

As a check pilot(and a very cautious pilot in general) I take exception to people who retract their flaps while still on the runway. I sincerely believe that such technique makes bad habits if you also fly an airplane with retractable gear: too many times I have seen people retract the gear instead of the flaps. Had just such an incident about two weeks ago at Merced: result, a very nice F-33 Bonanza is now a serious wreck.

SilverEagle2 · February 13, 2009, 08:54:50 PM

QuoteAs a check pilot(and a very cautious pilot in general) I take exception to people who retract their flaps while still on the runway.

My BE23 is placarded that one should "Raise Flaps to increase brake effectiveness."

I have found that if I do not raise my flaps, I will porpoise and skid so I have to remove the flaps as soon as I touch.

However, this requirement can be airframe specific.

Flying Pig · February 13, 2009, 11:10:36 PM

Quote from: bosshawk on February 13, 2009, 08:30:08 PM
Rob: the one issue that I could see would occur if you suddenly had to go around. Then, full flaps will cause a bad pitch issue until you can retract them. I admit that they act as good speed brakes, but in most cases you shouldn't need that much braking action. Your agency can afford brake pads, so don't be too soft on them.

As a check pilot(and a very cautious pilot in general) I take exception to people who retract their flaps while still on the runway. I sincerely believe that such technique makes bad habits if you also fly an airplane with retractable gear: too many times I have seen people retract the gear instead of the flaps. Had just such an incident about two weeks ago at Merced: result, a very nice F-33 Bonanza is now a serious wreck.

So as an experienced civilian and military pilot yourself, you'd recommend against my new found, self taught technique?

bosshawk · February 13, 2009, 11:57:42 PM

Rob: just my preference, but I wouldn't unless absolutely necessary to avoid going out into the "boonies". Brakes are there for a purpose, use them. I also concur with your practice of using 10 degrees for most landings: the 206 simply doesn't need any more unless into a very short field: then, the short field technique should do the trick, along with more flaps. As you know, I fly a 206 most of the time in CAP. In my Bonanza, I rarely use more than half flaps on a landing and it is a faster airplane than the 206.

Flying Pig · February 14, 2009, 12:34:16 AM

Quote from: bosshawk on February 13, 2009, 11:57:42 PM
Rob: just my preference, but I wouldn't unless absolutely necessary to avoid going out into the "boonies". Brakes are there for a purpose, use them. I also concur with your practice of using 10 degrees for most landings: the 206 simply doesn't need any more unless into a very short field: then, the short field technique should do the trick, along with more flaps. As you know, I fly a 206 most of the time in CAP. In my Bonanza, I rarely use more than half flaps on a landing and it is a faster airplane than the 206.

What was that?.....Sounds like a CHALLENGE!!!

caprr275 · February 14, 2009, 10:59:46 PM

What I was always told by the FAA was to NOT touch the flaps until off the runway. The FAA HATES when you start cleaning up your airplane and your still rolling on the runway. When you remove your flaps your attention is split and your not paying full attention to exiting the runway and getting on the correct taxiway .

Just a few things to think about.

es_g0d · February 15, 2009, 02:36:13 AM

The "FAA way" isn't always the right way, depending upon your type of operation. I agree, though, that most DPEs and inspectors I've asked about this topic agree that its generally poor technique to raise the flaps whilst still on the runway ...

EXCEPT when needed for maximum wheel-brake stopping power, when recommended by the manufacturer. Alas, there are very few absolutes in aviation!

One technique I'll throw out there for raising the flaps on the runway when required: USE ONE FINGER. It's far less likely that you'll be able to actuate the gear handle with one finger vice the flap switch.

I'm not advocating raising flaps for stopping, reference the reasons stated above. Furthermore, it is very seldom necessary in the real world. I'd intimate to you that if stopping distance is truly that critical then you likely won't have the performance to make it OUT of that field after your taxi-back.

Flying Pig · February 15, 2009, 02:49:50 AM

Now, just to clarify, Im not talking about raising them, Im talking about lowering them to full down AFTER you are on your roll out to decrease stopping distance. When I have done it in the past, I can really feel the plane lurch forward and slow considerably when they fully extend. So I know it does help. But I also dont want to develop any bad habits. I only have about 700 hours, so I am still a young pilot.

flynd94 · February 15, 2009, 02:52:04 AM

I would frown upon a student or if my First Officer added flaps after we touched down. In my current a/c Beech 1900D, I use nothing but flaps 17, unless we have a contaminated runway. Every AFM/POH I have ever seen says bring the flaps up to take the weight of the wings and, put in on the brakes.

They put brakes on a plane for a reason.

Keith

PS- I am true believer in NO configuration changes on the runway. Wait till you clear the runway. Look at the pro's, we leave everything where it is. What happens if you put more flaps in and, all of sudden you lose control (asymmetrical flaps). You might have a lot of explaining to do.

edited to add PS

Flying Pig · February 15, 2009, 02:58:34 AM

OK...well, thats a couple of pilots with experience that dwarfs mine who don't think its a hot idea. So I will abandon it. I guess if I want to stop that soon, I should just land with full flaps and call it good instead of inventing my own techniques on the fly. No pun intended

I read your PS. Good thinking. You know, I never thought about the asymmetrical flap deployment on the roll out. I was always taught that you shouldnt deploy flaps in a turn for the same reason. I imagine your evenly applied braking could go right out the window real quick if one flap fails to lower evenly. Thanks. Hadnt thought of that.

es_g0d · February 15, 2009, 04:21:11 AM

It sounds like what you're doing by lowering full flaps is some form of aerodynamic braking. I can't patently say that's wrong, but I would ask a lot of "why" questions if I was with you when you were doing it! A CE-206 isn't a BE-1900, nor is it a Supercub nor an F-16. As such, I can't recall any mention of aero braking in Cessna POHs. I think the bottom line is the same as the first one--its something that's possible to do (and perhaps do safely), but it would probably raise more questions than you have answers. That said, I do love a good discussion about aerobraking... its underutilized in our line of work.

flynd94 · February 15, 2009, 05:54:46 AM

Well, I can tell you this much if you want effective braking, you bring the flaps to zero, steady pressure on the the brakes and, keep the yoke in your gut. By leaving the flaps down, you are producing a small amount of lift, that in turn reduces the effectiveness of the brakes.

Yes, a BE1900 is no C206 but, last time I checked most planes fly the same way. Pull up, houses get smaller, push down houses get bigger. I would dare Flying Pig to use his "technique" on a CAPF5 or a FAA check ride and see what happens. I would see an UNSAT in his future, with remedial training with a CFI.

This is JMHO, of a guy who has been flying for close to 20 years.

es_g0d · February 15, 2009, 06:29:20 AM

You understand I'm not disagreeing with you, flynd94? With regards to WHEEL braking, you're spot on. And agreed, exhibit questionable techniques on a checkride and... you're leaving yourself at the mercy of the examiner.

Alas, I was waxing philosophic about aero braking ... not only underutilized but poorly understood as well!

LittleIronPilot · February 17, 2009, 07:31:53 PM

I understand the "dump the flaps" theory for maximum weight at 20 degrees or less...but my aircraft (C182) can go to 40 degrees of flaps...you 40!. There is NO LIFE with those barn doors hanging out there, it is all drag, enough that you can feel the forward movement slow when you deploy them.

Just for the record, I normally land with 30 degrees and only use the 40 for SHORT fields.

flyguy06 · February 18, 2009, 04:44:58 PM

As a one and a half year old CFI, i am really enjoying this discussion. I amlearning a lot. I to teach my students not to raise the flaps or push in carb heat until clear of the runway area. I want their attention focusedon landing and controlling the aircraft. Transitioning from flying the airplane to taxing ans traying on the centerline of the runway requires concentration and I dont want their attention deflected by messing with other stuff.

But after reading some of these comments, I am thinkoing a little differntly. I would obvioulsy try these techniques myself first b4 suggesting them to a student.

Again, great discussion. I had almost given up on CAPTalk, butthis is actually something meaningful that I can use. thanks

FW · March 05, 2009, 02:58:31 PM

This is a great topic for discussion. I can remember 2 times when I added full flaps when "breaking" for a stop after landing. Both times due to break failure. both times required engine stop and full flaps and full prayer mode. luckily, all worked both times.

Mustang · March 20, 2009, 04:02:20 AM

Quote from: Flying Pig on February 15, 2009, 02:49:50 AM
Now, just to clarify, Im not talking about raising them, Im talking about lowering them to full down AFTER you are on your roll out to decrease stopping distance.

You're operating out of FAT, correct? Plenty of runway, why do you care about your stopping performance?

As a matter of technique, however, adding flaps after touchdown might bite you should you encounter an unexpected gust. Better to leave them alone, or retract them fully.

Flying Pig · March 20, 2009, 02:34:56 PM

I am at KFAT but I fly and land all over the state. I spend a lot of time at Selma, Harris Ranch and Reedley on missions landing for fuel. Harris Ranch is like landing on a sidewalk! There are also a couple of private strips I am allowed to use as well that are shorter than Harris (3O8). I really have no problem hitting the numbers and getting stopped on any of them with only 10 degrees, sometimes 20. I almost never use 40.