IFR X/C Route Change, and a Flaps Discussion

caliginousface

Frank N. Beans
Just a question for you cloud surfers and teachers. Not so much of a problem with more wide open airspace, but in terminal areas like the SF Bay Area, it's most def not unheard of to have your filed route completely change. In this case, when you pick up your clearance before departure, do you have your students recalculate ground speeds, fuel burns, ETE's and so on? I remember during my instrument training they would totally change my routing but we'd just fly the new routing without recalculating. Any thoughts?

Then about flaps. I had a student fly with another instructor who ended up scaring my student out of extending flaps during extended downwind turning base citing "you increased your chance of a stall" by doing so. I thought about it, sure flaps lower stall speed, but the AOA at which you stall is now decreased, which i thought would only be an issue if you were pitching up while putting the flaps down. After going through that in my head, I still didn't feel it was worth freaking out about.

Hanyway, wasssuppppppppp.
 

tgrayson

New Member
another instructor who ended up scaring my student out of extending flaps during extended downwind turning base citing "you increased your chance of a stall" by doing so.
Not really clear on what the instructor said. Is it extending the flaps on extended downwind or extending flaps while turning base? As long as you don't allow the trim change to reduce your airspeed, you certainly don't increase the chances of a stall, but rather the opposite.

As for flaps during the turn, some people are a bit paranoid about that. The idea is that if you have an asymmetrical flap deployment, you have less time to regain control of the airplane if you're already banked. I've only seen a 2 or 3 people concerned about that in the past 12 years.

Unless you spoke with the instructor, there's a good chance your student misunderstood what the instructor was saying. You might consider asking the instructor to clarify his criticism.
 

meritflyer

Well-Known Member
Usually the route changes aren't significant enough to merit a full re-work of the performance data. However I will add up the new distance, take my average estimated ground speed, and fuel burn to get a rough idea of any changes especially, if I am risking my reserves.
 

MidlifeFlyer

Well-Known Member
You want to get a gross idea of how the change affects the flight time for fuel usage purposes, but recalculating a bunch of what were =estimated= speeds to begin with every time there was some course change or a new vector is some serious overkill.

On the flaps, there's a lot of that stuff = don't do it in a turn= going around. The two main reasons I've heard (that make at least some kind of sense) are that (1) if one flap doesn't work, the effect of the asymmetry is much more dangerous in the turn and (2) the changes in drag an configuration might result in a visual illusion (sort of like the "downwind turn" illusion) that could increase the risk of a stall.

For (2), I guess if you have problems with downwind turns, you ought not mess around with the flaps.

For (1), if you worry about the engine deciding to fail as soon as you extend your downwind beyond gliding in the pattern, you probably should worry about this too. Probably more since the risk is arguably greater.

:cool:
 

nosehair

Well-Known Member
extending flaps during extended downwind turning base citing "you increased your chance of a stall" by doing so.
It is a bad habit to routinely extend flaps during a turn.

(1)The beginning student has difficulty adjusting pitch and usually allows the nose to pitch up during the turn while extending flaps.

(2)Why are you extending flaps, anyway? To increase sink rate, usually, so the action should come after the base turn after looking at the runway and deciding to extend flaps, not for a rote flap-setting. What if you're too low, and should delay flaps?

(3) Other more practical reasons, such as flap split, or whatever, but the main reason, in training, is to break the rote pattern and induce some thinking and judgement, as in (1)&(2).
 

NJA_Capt

Well-Known Member
...scaring my student out of extending flaps during extended downwind turning base citing "you increased your chance of a stall" by doing so.
You never said how much flaps he was using. I would have to ask if it was an extended downwind why would you want to add flaps anyway? It requires you to add more power to drag the plane back to the runway. In training the basic principle is to remain within power off gliding distance in the pattern. Flaps decrease this distance. If you are outside the flaps up distance, why would you add flaps and make it worse?
 

caliginousface

Frank N. Beans
You never said how much flaps he was using. I would have to ask if it was an extended downwind why would you want to add flaps anyway? It requires you to add more power to drag the plane back to the runway. In training the basic principle is to remain within power off gliding distance in the pattern. Flaps decrease this distance. If you are outside the flaps up distance, why would you add flaps and make it worse?
I guess I shouldn't have said extended downwind, rather beyond abeam the numbers, turning downwind to base, applying 20 degrees flaps.
 

caliginousface

Frank N. Beans
It is a bad habit to routinely extend flaps during a turn.

(1)The beginning student has difficulty adjusting pitch and usually allows the nose to pitch up during the turn while extending flaps.

(2)Why are you extending flaps, anyway? To increase sink rate, usually, so the action should come after the base turn after looking at the runway and deciding to extend flaps, not for a rote flap-setting. What if you're too low, and should delay flaps?

(3) Other more practical reasons, such as flap split, or whatever, but the main reason, in training, is to break the rote pattern and induce some thinking and judgement, as in (1)&(2).
Thats good stuff but I don't tell them flaps have to be down during the turn. They look at the runway as their guide for how quick they need to be descending, and every now and then they know they are high turning base and extend flaps early like during the turn. But thanks for all the input guys, will take into consideration.
 

nosehair

Well-Known Member
and every now and then they know they are high turning base and extend flaps early like during the turn.
Notice I said, *routinely*.

After a *routine*, or *standard* habit pattern, then you should 'break it up' and deviate from the routine, or standard, to create thinking and adjustment to ever changing conditions.

It is just not good traing to allow 'sloppiness' in just 'slammin' down the flaps' with not much regard to where you are in the approach.

It's easy to do in a 152. Get lazy, I mean.
 
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