Have I missed something?

[DFC]

While observing a newly approved FIC instructor making a demo of a stalling brief to a student yesterday, I heard the folowing pearl of wisdom;

This aircraft stalls power off at 50Kt.

In the climb at full power it will stall at 55Kt.

This aircraft runs out of elevator authority at 60Kt and the nose will always drop.


I have no problem with the first statement.

However, if the 1g power off stall is 50Kt how can the stall speed with full power and 1g be higher?

Secondly, if there is not enough elevator authority to hold the nose up (maintain 1g) below 60Kt with the power off then how can one claim to demonstrate a power off 1 g stall at 50Kt?

Have I missed something over the years or are we about to get a rash of instructors who will be teaching utter rubbish?

Regards,

DFC

[jsf]

Where did he do his FI(R) course and does his CFI know what he is teaching? Did you correct the unfortunate individual?

When he/she flew the exercise I imagine the brief would have been demonstrated to be lacking.

jsf

[Johnm]

The higher speed with power on must surely be because the wing will always stall at the same angle of attack, so with power on the airspeed might well be higher at the same angle of attack. Running out of elevator authority at 60kts I can't figure out and look forward to wiser heads than mine with answer!

[Lawyerboy]

I'm lost. Ignoring for the moment the fact that I'm just a student so have no idea what I'm talking about, as to (2) I'm with Johnm - wing always stalls at the same angle so entirely possible that IAS could be higher but the wing still stalls in the climb (depending on angle of attack). However, running out of elevator authority at 60kt at all angles of attack doesn't make sense to me if stall in, say, s+l isn't until 50kt....?

LB.

[DFC]

jsf,

This guy is "teaching" future instructors and has CAA FIC approval. He is the CFI and he was previously the CFI of Jersey according to his intro!!!!!

No I didn't make any comment and decided to check that I haven't got it all worng for the past 30 years!

---------

lawyerboy and johnm,

In this case the aircraft stalls while at 1g at 50Kt with the power off. Or put another way, in level flight at 51Kt, the angle of attack is just at the stalling angle.

When full power is applied and the nose pointer upwards, the thrust vector is inclined and part of this vector is added to the lift. Thus with full power applied we do not need so high an angle of attack at 51Kt because the thrust is partly assisting lift. So it follows that with full power we will be flying at a lower speed than 50Kt before we need the stalling angle of attack to maintain 1g flight.

As for the elevator authority.......basically, this guy in one sentence says that if you close the throttle and allow the aircraft to slow while maintaining level flight, the aircraft will stall at 50Kt. He then turns round and says that the elevator is not able to keep the nose up at a speed below 60Kt.......so how does he get to 50Kt in the first place??????

I realise that you are a student and of course you will in time be given a briefing on stalling whic as you so correctly point out is related to angle of attack. However, don't mix up attitude and angle of attack!

Regards,

DFC

[IRRenewal]

Case 1: fair enough

Case 2: Two things. Slipstream effectively lowers the angle of attack, therefore decreasing stall speed. Vertical component of thrust also lowers effective weight of A/C and reduces stall speed as well. Stall speed with power on is lower than stall speed at idle power. Are you sure you heard him correctly?

Case 3: Are you sure this is what the instructor said?

[DFC]

IRRenewal,

I heard what he said OK. I also read the same thing from a handout he produced.

Having sat in to observe how instructor courses are run in the UK, I did not feel that I should correct what must be a CAA approved standard way of teaching instructors in the UK.

So is this guy teaching the same as everyone else in the UK? :confused:

Regards,

DFC

[jsf]

DFC

I don't suppose there is any danger that you walked in on a demo of how NOT to teach stalling!

As IRRenewal says stall speed with power on is lower than stall speed idle. That is usually stated for full flap and flapless in the POH for the A/C.

With elevator authority running out 10kts above stall, you are never going to be able to grease this baby on!

Let me know what type of A/C it is, I'll avoid it.

Is it that easy to become an FIC now....

But seriously though.........

Having said that, I just did a stint instructing away from my usual haunts and found differences in the way things are taught down there to the way I and my colleagues would teach. Not "bad" technique, but not what I would regard to be best practice. Not at the school I was teaching at, I hasten to add. But another on the same field.

There are maybe some standardisation issues at FIC level in the CAA. That one is down to the FIE's I guess....

jsf

[machonepointone]

As an FIE, if somebody came out with that sort of rubbish when I was testing him or her, they would fail the test. If it was an initial test I would discuss the matter with the school that "taught" him and, if necessary, take the matter up with the CAA. The FIC course is bad enough as it is without having individuals being taught to teach something so blatantly wrong.

DFC, the only thing that the CAA approve is the syllabus. It has practically no say in how it is taught.

As for the lack of elevator authority at low speed, it sounds as if the aircraft in question is one of those that has been designed to be "unstallable." This is a load of nonsense in its own right because if you were to fly at 100 knots and pull hard enough there would be plenty of elevator power to get the nose well up to the stalling angle of attack.

[Send Clowns]

I think I can comment, having not only been taught by a reputable shool (my groundschool instructor for my FI(R) had been an instructor for 50 years) but also having taught Principles of Flight at ATPL. DFC is entirely correct. The 1g stall speed of a conventional, certified aircraft will always be higher power-on than power-off. The aircraft could not be stalled if the nose dropped above stall speed, and this would suggest to me that the aircraft is way outside the C of G limits.

Assuming that he has correctly reported the briefing, this FIC instructor was talking garbage. That is worrying. I think someone should be told, starting with the student. However one would hope that, having passed at the very least an approved CPL groundschool course and have a couple of hundred hours or a CPL the student should have an idea him or herself. Perhaps just talk about it, to see if that is the case, confirm that the student is right in any doubts, and encourage a complaint. The paying customer complaining can sometimes get things corrected most quickly.

As Mach1.1 hints, we hear about many badly-taught FI(R) courses. help the students who suffer them do something about it.

[Tubbs]

I don't think that this necessarily indicates a badly taught FI course, as the course doesn't aim to teach basic aerodynamics. To me, this sort of teaching is representative of someone who didn't learn the basics properly and has got through the rest of the training without revising his/her incorrect base facts. The FI course is more about how to teach rather than dragging you through the whole ATPL syllabus again.

Rather than ranting about the poor standard of FI course instruction, I would look at the JAR PPL and ATPL syllabus and think about how the emphasis has moved from understanding principles to passing exams. I know people who got through the exams by focusing more on exam technique and past papers and less on application of fundamental principles.

My FI(R) course was taught extremely well and I'm getting a bit pissed off with the snotty attitude of some people towards modern FIs. I went through PPL training in 1993 and back then the standard of training was not different. Some are good, some are bad. Some teachers have the bedrock theoretical knowledge and some don't.

God save us from a 'rash of instructors who will be teaching utter rubbish'. Bugger off mate.

[Send Clowns]

Tubbs

Note this guy was teaching FI(R)s. That is the next stage up, and anything he says must be basically correct, aerodynamically!

[benchmark]

Send Clowns,

I think you have contradicted yourself old boy....

"The 1g stall speed of a conventional, certified aircraft will always be higher power-on than power-off"

If that's the case then the chap in question was not talking garbage. He was however, and you have got yourself mixed up.

[Angel´s One Fife]

Doesn't surprise me. I know of an FIC approved guy who recently failed his own instructor renewal three times in a row and is still teaching FIC. And he was based at an integrated school! There are many rubbish instructors around these days who have been taught by fools like him. What was worse was the CFI still let him teach in the sim.

[DFC]

"To me, this sort of teaching is representative of someone who didn't learn the basics properly and has got through the rest of the training without revising his/her incorrect base facts"

So that means that this individual may have got it wrong at PPL training and then received the wrong info during CPL training and during instructor training and at no stage has this ever been picked up.

This individual must have done the stalling exercise on at least 1 instructor renewal test so the FIE must have missed it.

However, leaving the individual case behind, what system is in place for instructor quality control. i.e. do the CAA actively seek reports of the above or do they rely on the instructor/examminer/FIC/CFI to effectively quality control themselves?

Regards,

DFC

[Send Clowns]

Ooops, you're right, benchmark. I knew what I meant, just wrote the opposite! Yes, the stall speed is lower power-on. Sorry!