J170C full flap baulked landing characteristics.

[Guest Ken deVos]

While practicing forced landings in the J170C, I managed to set the aircraft up into an unexpected situation that perhaps warrants further discussion.

 

The decent with power off was normal, field selected and finally full flap deployed with airspeed having decayed to about 55knt. Satisfied that I would make the field, I smoothly applied full power while simultaneously pushing the stick forward. The nose began to rise as expected and more forward stick applied. However, the nose kept rising at a steady rate despite now applying full forward stick!

 

Concerned at the uncontrollable rising attitude, I killed all power, waited for the nose to lower, then slowly reapplied power. This time I ensured the elevator maintained authority before full power was finally applied. Once established in the climb, flaps were slowly retracted and normal flight ensued.

 

The aircraft was loaded with about 58kg fuel; myself plus flight bag at say 80kg and nothing in the back behind the seats.

 

 

[motzartmerv]

whoa..dude.. Don't do that again will you... Apply full power and raise the flaps to take-off position.. Do it in that order, as soon as the power goes on bring that flap up and control the attitude.. Watever you do, don't get into the habbit of reducing power to lower the nose, especially at low level like that..

 

With all that flap out and full power on the extra lift created from the inboared sctions of the wing can be to much to be overcome by the corective forces on the tail plane..This isn't the case with the 160 but obviously is with the 170..

 

So to recap..

 

1. Apply full power

 

2. Raise the flaps to take-off position

 

3.control the nose attitude with elevator

 

4. Assume the normal climb attitude.

 

You said you were at 55 kts, then applied full power and the nose came up..

 

So now your in a new configuration, ie, high nose attitde and low speed, sound familliar?? perhaps from your lessons on "stalling".. So then you reduced power. So now your slow, a high nose attitude, and no power on.. Ya see what im cooking??

 

So....please...don't do it again...:thumb_up:

 

 

[Steve L]

I too think you had too much flap for the elevator to overcome. I"m a low time student flying a 170, and once while milking the flap off from the first stage after take off I went the wrong way with the switch. It was just momentarily and I thought it wasnt enough to alter the flap but the Jab did pitch up quite noticably and i'm sure that if I had kept lowering the flap at that slow airspeed I would have had a stall to contend with. I would have considered milking the flaps very carefully after applying full power the first time, maybe this is wrong but as a said im a low time student 16 hours and with the exams out the way im heading for my first solo.

 

Steve

 

 

[Guest Ken deVos]

....This isn't the case with the 160 but obviously is with the 170..So to recap..

 

1. Apply full power

 

2. Raise the flaps to take-off position

 

3.control the nose attitude with elevator

 

4. Assume the normal climb attitude.

I have not experienced this in either the LSA55 or J160 and characteristic may be peculiar to the J170. However, I was taught to reconfigure flaps last, as described in the theory books, but I do intend discussing this with the CFI soon.

 

Since the J160/170 takes four seconds to retract full flap back to 1st stage, if flaps need to be raised as soon as power is applied, then the problem will be at its worst when a go-around is required within 4 or 5 seconds from the landing flare (ie full flap, 55knt, 50ft agl). Also, will the aircraft sink when flaps are retracted at this time?

 

I know that the stabiliser/elevator is larger on the J170 than the J160. I wonder what the J170 would do if it was loaded differently, especially with more weight behind the seats.

 

 

[Guest brentc]

I had intended to jump in the 170 and try this on the weekend but forgot all about it.

 

Part of aircraft certification is it's ability to fly with a positive rate of climb with full flap applied.

 

Based on this I would expect that as long as it's within the correct C of G range that it will comfortably fly with full power and full flap.

 

Perhaps when you are up next, try this procedure at a safe altitude and you'll find that all is ok......

 

 

[Guest Ken deVos]

...Perhaps when you are up next, try this procedure at a safe altitude and you'll find that all is ok......

Yes Brent, it's on my to do list. Unfortunately, I ran out of time in the training area and the CFI was busy with a student when I returned.