C172/Full Flaps/Ac veered off runway

[extricate]

Hi,

 

I've read a report about a student pilot who forgot to flaps up after touch n go, and the aircraft veered off the runway even after kicking in right rudder. I'm trying to understand why it happened and would like more advice on this.

 

With full flaps, could it be that even with full power, due to the disruption of airflow around the aircraft (slipstream effect), the flaps rendered the rudder ineffective in directional control and as a result, the aircraft could not get back on track?

 

Many thanks

 

 

[mnewbery]

What were the weather conditions at the time?

 

 

[SSCBD]

Pure Guess on above - aircraft in " full flap ground affect ", and had virtual no weight on nose wheel so that was ineffective - then I assume just late on rudder and amount of rudder , student thinking the nose wheel would steer it on ground. With full flap and at takeoff power they get a very flat takeoff configuration and very, very hoppy.

 

Again pure guess on what happened. .

 

 

[extricate]

What were the weather conditions at the time?

Wind conditions at that time max crosswind of 10kts, no gust.

 

 

[Camel]

Hi,I've read a report about a student pilot who forgot to flaps up after touch n go, and the aircraft veered off the runway even after kicking in right rudder. I'm trying to understand why it happened and would like more advice on this.

 

With full flaps, could it be that even with full power, due to the disruption of airflow around the aircraft (slipstream effect), the flaps rendered the rudder ineffective in directional control and as a result, the aircraft could not get back on track?

 

Many thanks

A C172 has a lot of drag with full flap 40deg and does not want to take off ...it will fly but very slow and hardly climb, the manual says return to 20 deg immediately for be able to climb from memory ! I don't think it could effect rudder directional control ! Look forward to other comments !

 

By the way with 40deg and carb heat on I don't think it will get off the ground unless it was a very cool day at sea level.

 

 

[kaz3g]

A C172 has a lot of drag with full flap 40deg and does not want to take off ...it will fly but very slow and hardly climb, the manual says return to 20 deg immediately for be able to climb from memory ! I don't think it could effect rudder directional control ! Look forward to other comments !By the way with 40deg and carb heat on I don't think it will get off the ground unless it was a very cool day at sea level.

Get the flaps down to 30 or less with it on the ground if at all possible because at 40 it will fly like a dog and will not climb unless terribly close to stall speed. Heaps of drag and not a lot of lift.

 

Kaz

 

 

[Yenn]

like a dog it may be but it will still fly, very nose down. But if a student didn't realise that he had full flaps, he probably wouldn't realise the nose was down. We keep hearing about accidents where the rudder doesn't get the use it ought to.

 

 

[jetboy]

The C172 with full flap takes for ages to reach the "as taught proper rotation speed" for takeoff so the nose gets held low until that speed is reached. By this time the mains are off the ground and its in a wheelbarrow situation. Plenty of entertainment for the tower.

 

dont ask me how I know

 

 

[ben87r]

I would suggest that the aircraft had insufficient rudder authority due to a low IAS, with full flap they can get off the ground at a surprising low speed, but won't venture far from there. Add in a little bounce on landing, and then tried to fly away that would result in a high AoA situation and a slower speed again now with no nose steering or directional breaking, possible for the pilot to then either find full rudder isn't sufficient or only apply the expected amount of rudder and not get the required performance.

 

I don't see it being an aircraft issue and depending on which way the aircraft vacated the runway, slipstream may have even been of benefit.

 

One light single I've flown a bit had no nose wheel steering and felt like at had a "no mans land" between having enough speed for sufficient rudder and having the aircraft grounded enough to use the directional breaking. Was very off putting.

 

Ps the above was actually due the the ridiculous speeds the flight school mandated on final (Vref +15) and the excessive float, was no fault of the aircraft.

 

 

[Downunder]

I saw an aircraft leave the runway on takeoff recently. 4 things I noticed.

 

1. Aircraft was at full flap after landing, taxiing back and going again. (I'm told wrong config.)

 

2. Wind was across the strip from the left. (Pushing tail right)

 

3. Engine torque from full throttle, low airspeed pulled aircraft to the left.

 

4. Speed was too slow for rudder to affect direction. (Continued to turn left)

 

All the holes in the cheese lined up and the result was an excursion on to the grass.....

 

 

[facthunter]

A lot of things are potentially wrong. The plane has a lot of drag, the stick is usually hard to push forward sufficiently, as it's out of trim once you power up.. If you aren't ready for it you won't manage it too well. Nosewheel contact (lower than the mains) is likely.... High power?, Hardly but, at low speed will cause left turn so need a lot of right rudder. Crosswind from the wrong side may also need rudder. In any sort of crosswind with that plane I wouldn't use full flap. You would have a pretty steep approach with power off and if you did a powered approach you will get a direction change when you remove power if you don't use positive rudder to correct it. In a crosswind you would want wing into wind down during the initial part of the go around till you are sure you won't get ground contact. It would also be wise to reconfigure to flap 30 to get more performance as soon as safe to do so. Depending on temperature, altitude and weight it's maybe not going anywhere with flap 40. Nev

 

 

[mnewbery]

I'm not sure the designer(s) ever expected zero forward speed plus full flap plus 10 knots XW plus full power.

 

Max demonstrated is 15 knots for some C172 models and this would be typical.

 

Generally I try not to be a test pilot in a plane I'm flying. I'm reading a C172N manual for a flight tomorrow. That scenario isn't in there.

 

 

[diesel]

I thought 40 degree flaps disappeared with the big handle years ago.

 

The later electric ladder was terrible. At least you could look out the window to see where they were.

 

Chas

 

 

[Roundsounds]

I'm not sure the designer(s) ever expected zero forward speed plus full flap plus 10 knots XW plus full power.Max demonstrated is 15 knots for some C172 models and this would be typical.

 

Generally I try not to be a test pilot in a plane I'm flying. I'm reading a C172N manual for a flight tomorrow. That scenario isn't in there.

If the holder of a Pilots licence cannot handle a C172 in 10kts of crosswind, they should go and do a tailwheel endorsement including 3 point and wheeler crosswinds at the max for the type with a competent instructor. That will sort out their crosswind landings.

 

 

[frank marriott]

If the holder of a Pilots licence cannot handle a C172 in 10kts of crosswind, they should go and do a tailwheel endorsement including 3 point and wheeler crosswinds at the max for the type with a competent instructor. That will sort out their crosswind landings.

If a pilot can't handle 15kts of Xwind in a C172 at 0 and up to 40° of flap then they shouldn't be solo, period!

 

 

[diesel]

Thats the advantage of not having a cross runway.

 

You learn to deal with it.

 

Chas

 

 

[Roundsounds]

Th

 

If a pilot can't handle 15kts of Xwind in a C172 at 0 and up to 40° of flap then they shouldn't be solo, period!

Current training seems to place emphasis on playing with as many electronic gadgets you can fit into a cockpit, doing all procedures using written checklists, talking non stop on the radio and less on basic stick and rudder skills.

 

 

[Roundsounds]

Thats the advantage of not having a cross runway.You learn to deal with it.

Chas

The advantage of crossing runways - if there's wind you can always find a crosswind.

 

 

[Pearo]

I got spoiled, I learned at an airport in a 172 that has a regular 10-15knot crosswind. Post christmas, the crosswind blows through the hangers, so when you think you are about to touch down you get a gust that makes you go flying again....

 

Beside the point. I was taught to do a T&G with full flap(30 degrees in the 172 I was flying) because a solo student had a flap retract failure. It works, but climb performance is atrocious and its going to be a 500ft circuit at best.

 

 

[diesel]

WTF?

 

If you have to get out again in a full flap cessna you must get that trim rolled forwards four palm fulls as it acellerates again.

 

Dribble the flap off as it gets going and fly normally.

 

Chas

 

 

[Pearo]

WTF?If you have to get out again in a full flap cessna you must get that trim rolled forwards four palm fulls as it acellerates again.

Dribble the flap off as it gets going and fly normally.

 

Chas

Or you just fly the plane and deal with it at a safer altitude.

 

 

[ben87r]

Or you just fly the plane and deal with it at a safer altitude.

Haven't flown the 172 but the Cessna singles I've flown, the first baulked landing checklists item is flaps 20 immediately.

 

 

[diesel]

A slowed up full flap trimmed 172 has a huge trim change when full power is applied.

 

If you dont get onto that trim wheel immediately

 

as part of the cleanup you will be busy.

 

Those old steering wheel things take a lot of pushing and non farming types may not handle it.

 

It would not be the first one to break. The older ones are full of corrosion in the tubes.

 

All ok if you do it right.

 

My old instructor in the 60,s said he could flight test anyone with one landing and overshoot.

 

Chas

 

 

[facthunter]

Coupled with worn seat rails where the seat goes back at any steep pitch angle and you can't reach the controls. The force required to push the stick forward could catch the unwary and makes accurate pitch unlikely unless you are anticipating it. The other problem is lost performance, (climb rate and acceleration) The 172 doesn't have a lot of that either with 3 or 4 on board and may have none to spare with the flap in full down position. Nev

 

 

[MikeWebb]

Hi,I've read a report about a student pilot who forgot to flaps up after touch n go, and the aircraft veered off the runway even after kicking in right rudder. I'm trying to understand why it happened and would like more advice on this.

 

With full flaps, could it be that even with full power, due to the disruption of airflow around the aircraft (slipstream effect), the flaps rendered the rudder ineffective in directional control and as a result, the aircraft could not get back on track?

 

Many thanks

A lot depend on which model of C172 we are talking about. The old models had 40 deg flaps and would not go round at full flap. This would have prolonged an attempt at lift off and any crosswind would have been an issue. In any case the P factor will cause a veer to the left unless you are aggressive with the rudder when you apply full power. I think this is just a case of a low time pilot meeting a condition he/she had not met before. We have all been there at some point.