Flap setting on walkaround

[pelmet]

I am considering modifying my procedure as suggested here after reading this blog. Any comments.

"Multiple blogs ago, we discussed the wisdom of preflighting flaps by running them full down on the walk-around. That subject was about a fatal accident in Detroit involving a heavily loaded C-172. Witnesses saw the aircraft takeoff with full flaps, struggle into the air, and crash—four fatalities. If inclined, you can reread the commentary and opinions, which slightly favored following the manufacturer’s checklist. That means if it’s on the list do it—if not, it’s optional.

There was another flap accident (also fatal) last week involving a C-150 that resulted in the loss of a 20-year old student and his 33-year old CFI. My usual disclaimer about preliminary speculation applies, and you may chime in with similar protection. The sea-level runway had a density altitude of perhaps 2,000 feet in summer temperatures. The runway was 3,700 feet with an estimated 500 yards of overrun before encountering more than 50-foot trees. Witnesses saw the 150 take off with full flaps and barely get airborne in ground effect.

After getting airborne, the flaps were retracted; the aircraft climbed slightly, appeared to be out of ground effect, and wobbled before nosing straight in. The CFI had mentioned to one of the witnesses that he had been up much of the night with a sick child, raising the issue of potential fatigue.

What happened here, in my view, was not a long chain of judgment errors but rather a lapse. A lapse is where one omits or commits just one action that triggers the event. Other examples would be an altitude bust or forgetting to raise or lower the gear. There are actions to guard against them, but sometimes—despite long rants here and elsewhere—the path to catastrophe can be brutally short and swift.

A couple of quick thoughts for your consideration since we’ve hashed this out before:

1) Leave the flaps up on preflight. You’ll find out soon enough if they work—either on takeoff or landing—before getting to a critical situation. This is my personal favorite—the preflight flap craze appears to have come into vogue in the 1990s, perhaps after somebody got sued.

2) If you insist on checking flaps during the preflight, set them no lower than to the max lift setting. In most Cessnas, for example, that will be 20 degrees. That way, if they’re forgotten before takeoff it won’t be a disaster.

3) Another technique, if your aircraft system allows, might be to lower the flaps, turn off the master switch, and then position the flap switch to up so they will automatically retract when the master is turned on for engine start.

4) Fatigue, illness, or medication increases our ability to lapse. That leads to the judgment issue preceding the lapse of whether today’s flight is a good idea. You can see where that is going and something we’ll discuss in the future.

My office overlooks the ramp, and I’ve seen more than a few aircraft taxi out with flaps still down: One lapse away from a major problem? So far this year, there have been six fatalities due to a procedure that was designed to prevent them. The law of unintended consequences applies here. I know pilots shouldn’t be making basic mistakes, but good luck with that line of thinking. Better to avoid putting yourself into a bad situation than to always avoid the small but deadly lapse. That’s called risk management.

Your thoughts?"

[photofly]

It can be advantageous to lower the flaps for an inspection. If the push rods are no longer straight (not something you'll see from the air) then it's likely a flap overspeed was done under the supervision of a previous PIC. If you spot it on the ground you can avoid flying a damaged plane and avoid getting the blame for it.

On the subject of checklists:

"Wing flaps - RETRACT" appears in the POH Starting Engine checklists for the 172.

"Wing Flaps - Set for takeoff (0-10°)" appears in the before takeoff checklist for the 172 (too lazy to look at the 150 right now, but I"m sure it's there too.

The correct flap settings are given again in the "Takeoff - Normal Takeoff" and "Takeoff - Short Field Takeoff" checklists.

That's three separate opportunities *not* to leave the flaps down, if you follow the printed procedures.

At some point there has to come a "buck stops here" responsibility for correctly configuring the aircraft for whatever phase of flight you're in. I don't know if this is such a point, but to follow your example, why not have a checklist to make sure that the flap position switch was positioned to "up" after the master switch was turned off, in case *that" procedure was forgotten?

[jschnurr]

At all the FTUs I've either been a student at or instructed at, it was always flaps full down for the walkaround. At the 703 job, I never put flaps down... if they were broken, the previous pilot would have snagged them, or I would find it on the taxi out.

Some will say that the flaps need to be cycled through their whole travel to find any malfunction in the system, but I don't buy that. The extremely remote chance of the flaps working at partial extension and not at full extension, to me doesn't outweigh the hazards of flap extension in the ground. Extending full flaps on a low wing in the hangar carries the risk of damage if something is left under the wing. And with a high wing, I've seen dozens of people smack their heads on the fully extended flaps. Besides, if the flaps work on the ground, how can you be sure they will work in the air with the additional air forces? Extending flaps on the walkaround, doesn't have any net benefit to me.

[LousyFisherman]

Taking off with full flaps on a 150 or a 172 means that the pilot ignored the handling of the plane on the takeoff roll. I mean. neither accelerates worth a damn with full flaps. In fact I am amazed a 150 can get off the ground with full flaps. Must be something to do with low density altitudes.

2800 feet is what I need for a take off at a density altitude of 7000 feet.

Neither of these accidents were because the flaps were left down. Both were caused by the pilots choosing to ignore the poor performance of the plane on the takeoff roll.

IMHO
LF

[cgzro]

The most dangerous situation with flaps is an asymmetric deployment. You are usually low and slow when you put them down and if they come out uneven it could be deadly. Id suggest that all control surfaces and engine controls should be checked on the ground before you start the engine where a problem hurts nobody.

It also sounds like the plane was spun / snapped in, otherwise it would not 'nose in' it would mush in without anywhere near as much likelihood of killing people. So not only were flaps left deployed but the ensuing stall was not correctly dealt with.

[Posthumane]

As photofly mentioned, it's in the checklist several times so it's not just one oversight. Also, one of the pre-takeoff checks involves looking at the control surfaces to make sure they move in the correct direction, at which point it would be difficult not to notice the flaps are still down. My on-runway mental check is Fuel-Flaps-Mixture-Time-Transponder-Track, where I touch the flap handle to make sure it is in fact fully seated (my aircraft has the old handbrake-style lever for the flaps).

One time where it IS likely to leave the flaps down is when doing continuous circuits. Someone doing a simulated short field landing with full flaps, perhaps landing a little too far down the runway, could get in a hurry and just pour on the coal to get airborne again without reconfiguring the plane. Again, though, as LF mentioned it should be pretty obvious that something is wrong when the plane isn't climbing.

A family member who was doing a night checkout in my plane left the flaps down once during a circuit. Because it was night, and that runway (CFX2 16) had a bit of a black hole effect at the time, at first he thought it was a pitot-static failure since the airspeed started falling as he was climbing. I can't remember what made him change his mind, might have been a stall horn beep, or perhaps the instructor noticed it... That wasn't with you, LF, was it?

[photofly]

One time where it IS likely to leave the flaps down is when doing continuous circuits. Someone doing a simulated short field landing with full flaps, perhaps landing a little too far down the runway, could get in a hurry and just pour on the coal to get airborne again without reconfiguring the plane. Again, though, as LF mentioned it should be pretty obvious that something is wrong when the plane isn't climbing.

I've done (or perhaps more accurately I've been subjected to) many such takeoffs in both 150s and 172s. It's no different than a go-around with full flaps. I've never had a problem leaving the ground and fixing the problem in ground effect. Or in the climbout. Clearly the performance is sensitive to load and density altitude, and I don't report this to recommend the technique. Merely to point out that it is not inevitable death that results.

[ahramin]

I don't think you can attribute those accidents to a walkaround procedure. Flaps up would be a part of the after start, and flaps set would be part of your before takeoff. So 2 items to be missed. Plus a proper control check before takeoff will have you looking out at both wings twice so more opportunity to catch it. Proper checklists (not 2 pages long) and discipline is what prevents takeoff configuration accidents. Trying to cure it by changing your walkaround would be like preventing gear up landings by leaving the gear pins in.

However, as far as the walk around itself is concerned, I never put the flaps down for a normal walkaround. I have never seen an AFM or FCOM that requires or recommends it.

[cgzro]

Actually given that weather /VFR into IMC and fuel starvation are the two most common acidents you could almost certainly skip a flap check and instead spend a minute more checking fuel and the weather and come out way ahead safety wise

[danishroy]

Like mentioned by a member here. I dont think the walkaround is to blame. I'm currently still doing my ppl. I was taught to put the flaps down during walkaround. Iv never had a flap down situation, there's so many times where you have to make sure flaps are set for take off and when you do control check you should notice the flaps are set wrong. I think those accidents are due to omitting check list items.

[Rookie50]

Usually leave them up, but it's my plane. A rental, I'd drop them.

On mine, they go down 20 for takeoff, I glance each side, if down together, don't expect future problems.

Fuel, oil, weather, seem more critical --

[SuperchargedRS]

I preflight with my flaps up, small aircraft all the way up to turboprops.

[North Shore]

I run my flaps through their range during the preflight, as per the checklist, and then they are left up until the pretakeoff check.

Edited to add: now I have a little coffee in me, and see that this is about C172; as I rent, I run the flaps down, walk around, and then set them as necessary for t/o

[Chris M]

I run them down to maybe 20 degrees, largely because in the 172M I don't feel like standing there holding the flap toggle to drive them all the way down to 40. Also means I don't have to duck down so far to cross them. It's a rental so I feel it's worth taking the time to make sure nothing's been broken since the last time I flew it. As mentioned there are ample opportunities both as checklist items and looking in the area to verify that they're configured for takeoff.

[Posthumane]

I put mine down for the walk around. It takes a second to do with manual flaps and draws no current. Not only does it allow me to see the pushrods and hinge rollers, it lets me check if the flaps are frozen to the underside of the wing, which I've had happen a few times due to a crappy flap-gap seal which tended to trap moisture. I'd rather find they are frozen before I went through the run-up and taxied out to the runway.

[PilotDAR]

Follow the manufacturer's recommended procedures - that's why they were written and approved.

Through any meaningful pre takeoff check, the flap position will be confirmed as correct. If not, the pilot discipline has failed. "Changing" or making up your own procedure to pre-empt a failing you might make is wrong - just follow the procedures already present for the aircraft. There is no excuse for beginning a takeoff with the control's not checked and the flap and trim position confirmed as correct (and fuel to the engine too).

It is a basic requirement of pilots that they confirm the configuration of the aircraft. Configuration assurance is the pilot's responsibility, and it's simple: Next, I am going to XXXX with this plane. For that I know that I will require ABCD configuration. Is the plane in that configuration? I will now check.

many such takeoffs in both 150s and 172s. It's no different than a go-around with full flaps. I've never had a problem leaving the ground and fixing the problem in ground effect. Or in the climbout. Clearly the performance is sensitive to load and density altitude, and I don't report this to recommend the technique. Merely to point out that it is not inevitable death that results.

Photofly is right. Any pilot who crashes any aircraft following a full flap takeoff is inadequate to the plane. Few types specify full flaps for takeoff, but all certified light aircraft can safely do it, or they will not be certified. This, for the reason that the flap system can fail during an overshoot, and it is required that the aircraft be able to climb away safely. But, of course, use the recommended flap setting for takeoff.

If you are flying an unfamiliar aircraft, and you intend to use something in that aircraft during the flight, it is wise to confirm that it works priot to takeoff. My preference is to always use full flaps for landing, so I check their correct function in unfamiliar aircraft. I have had a flap jam and become asymmetric while flying a Cessna 180, so a preflight check is worth the effort. Unfortunately, preflighting the flight controls on a floatplane is not as easy as a wheelplane, so the hands on, eyes close element tends to be overlooked.

When flying a 150/172, it's worth using that opportunity to "become at one" with the plane. Understand the checklist so you are using it as a checklist, not a "to do" list. It is a "light touch" tool to assist you in confirming that you're doing it right. Avoid depending upon it to assure your configuration. Certainly avoid complicating it further by changing it! It won't be long before you're flying something more complex, and then you'll really be in trouble if you're home making your checklists!

The discipline of the cockpit is to some degree a language in its own. When spoken correctly, it'll be darned close to what the manufacturer of the aircraft has had approved. If you go somewhere else, and the person (instructor?) who is checking you out sees you applying home made procedures, they're going to question why. You don't want that, because if the check pilot is questioning, that's costing you money. They expect you to follow the manufacturer's procedures. If the see that, that box is ticked, and you're on to the next. If they see you do something different, you're paying them while you explain why.....

Operate the way the flight manual says to, and use your skill as a pilot to assure configuration prior to every change in phase of flight. Then refer to the manuacturer's cheklist to assure you were thorough.

And... When you see Transport Canada or FAA "approved" on a blog, take it as the gospel. Otherwise, read with great caution!

[davecessna]

The most dangerous situation with flaps is an asymmetric deployment. You are usually low and slow when you put them down and if they come out uneven it could be deadly. Id suggest that all control surfaces and engine controls should be checked on the ground before you start the engine where a problem hurts nobody.

It also sounds like the plane was spun / snapped in, otherwise it would not 'nose in' it would mush in without anywhere near as much likelihood of killing people. So not only were flaps left deployed but the ensuing stall was not correctly dealt with.

That's an excellent point I was actually just going to post as well. Try a "by-the-book" short field landing on an icy runway with a strong headwind. If the flaps come up unevenly, get ready with those dancin' feet.

[rxl]

As he usually does, PilotDAR nails it. +1.

[DanWEC]

I agree. Not deploying the flaps on the walkaround because of an unfortunate error is akin to filling the tank right to the collar before each and every single takeoff, no more touch and goes, just because a few people have forgotten to check the fuel and ran out while flying. Ignoring the several flap items in the checklist is poor pilotage, not a systemic problem.

In a 172, and some other Cessna products, it's prudent to physically check the flap linkage rod, and also give the flaps themselves a good tug. No other way to do it besides with the flaps down.

I found a broken wire in the 337, hanging on by 1 strand, by cycling the flaps during the walkaround. It seemed like something was binding because the motor would slow down and almost stop several times during the cycle, but it was just the poor connection that was probably one flight away from breaking completely. Wouldn't have found it any other way since you can't quite hear the flap motor very well while in flight.

Current turboprop 703, both types, get a full cycle flap and position check, each preflight.

I actually did use a checklist at an FTU that had the "Master off, flap selector up" sequence. It gives you one more thing to look outside at when the master goes on again, but it does solve the issue.

[JasonE]

You'll never forget on the Piper Cherokee to raise them. I have to lower the handle to climb over to the pilots seat!