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stall warning - audio buzzer


johnm

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Being inclined to have the head in the cockpit is something we should be wary of. I don't recall too many Pitts being involved with stall incidents. if you fly that kind of plane you should be a bit above average in this kind of knowledge and experience. if you were engaged in a dogfight where the turning radius must be tight and you are right on the edge of stall, You wouldn't be looking at an AoA readout in the older type of planes in those circumstances. (which is what we relate to). Nev...

 

 

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The only problem with the increased use of EFIS in light aircraft being they foster a head down method of flying. EFIS has a place in aviation, particularly IMC op's. I fear we will see an increase in midair collisions / near misses.

Head down flying could be a concern, except that I know I can keep by eyes outside where they belong, and rely on Dynon's numerous verbal alerts. That way my visual attention is only drawn inside when something is amiss (eg. various pressure & temperature warnings when out of safe range, airspeed, g forces, etc..). That doesn't mean I don't regularly scan my instrumentation, but knowing I get verbal warnings from the system allows me to maintain normal vigilance outside the cockpit.

I also have a cheap ADS-Pi device delivering ADS-B & Oz Runways traffic to my iPad, alerting me to traffic far sooner than the best eyes can pick them up, so my iPad deserves a glance every now and then for conflicting traffic.

 

Sorry if this is a bit of thread drift...

 

 

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The continued anti technology attitude displayed in this forum is frustrating. The modern technology has the ability to provide audible warnings that means that the head can be out of the cockpit.

 

The "seat of the pants feel" as you approach the stall changes significantly in a steep turn. The increased G loading results in a higher stall speed in the turn and the higher airspeed means that the controls still feel effective and heavy at the stall, making it hard to "feel how" close you are to a stall. It is why the turn base to final is so deadly.

 

 

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When did you last practice stalls and slow flight?

 

I may be odd but I enjoy slow flight and stalls. I regularly enter the pattern without flaps in the RV4 at less than 70 kts, that is some 5 knots above the stall and on final if a wing drops I use rudder rather than aileron, even though i know the aileron will work OK.

 

Get out and pracice, but at a safe height first, you never know you may get to enjoy flying with the controls feeling soft.

 

 

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I don't think anti technology is the word for it but there is a tendency to over instrument many planes because more is better and it doesn't cost extra to have the lot, so why not.? No instrument tells you how you are tracking on crosswind or base for example. You have to look outside. A glider can be flown very effectively with a tuft of wool. Slip and AoA are indicated by the wool. You SHOULD be capable of doing a circuit with airspeed inoperative. Hopefully you will err slightly on the fast side. Indications can be erroneous. Following a failed instrument has been known to kill. I love GPS, but there's an old rule. Never trust ONE instrument alone. There should be confirmation/checking by an independent source. Nev

 

 

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I don't think anti technology is the word for it but there is a tendency to over instrument many planes because more is better and it doesn't cost extra to have the lot, so why not.? No instrument tells you how you are tracking on crosswind or base for example. You have to look outside. A glider can be flown very effectively with a tuft of wool. Slip and AoA are indicated by the wool. You SHOULD be capable of doing a circuit with airspeed inoperative. Hopefully you will err slightly on the fast side. Indications can be erroneous. Following a failed instrument has been known to kill. I love GPS, but there's an old rule. Never trust ONE instrument alone. There should be confirmation/checking by an independent source. Nev

I think we are in agreement, but just with different emphasis.

 

When I fly, I actually have 5 independently powered GPS moving-map devices on board. Two are on the panel. Years ago, a (now corrected) software glitch "froze" my Dynon upon circuit entry to (a fairly busy) Broken Hill. That left me with 4 sources of ground speed (not as good as IAS, admittedly). It was a fine VMC day and I simply continued the circuit to land there uneventfully, all by "feel" and an occasional glance at ground speed from the secondary GPS on the panel.

 

I've flown rudimentary gliders in the 1970's and appreciate the tuft of wool "instrument" as much as anyone. Regardless, I'm a BIG fan of technology WITH redundancy. Keeping my head out of the cockpit is just as natural as it always was, but the modern audible technology now helps me keep it there (not on an old e6b wheel with paper maps & scribbles).

 

 

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There's a lot of people trying to sell you gadgets out there. Gyro instruments cost a fortune to buy and keep legal so modern may be a better way to go there, but I'm a fan of a turn needle proper rated. GPS has the same source and someone could turn it off at will. The tendency to over instrument concerns me more than people flying with less than needed. The original B 747 Jumbo had so many warnings they got rid of more than half of them. Distraction is the thing to avoid when flying. Everglades... changing an undercarriage indicator bulb with 3 crew and no one flying the plane. Nev

 

 

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There's a lot of people trying to sell you gadgets out there. Gyro instruments cost a fortune to buy and keep legal so modern may be a better way to go there, but I'm a fan of a turn needle proper rated. GPS has the same source and someone could turn it off at will. The tendency to over instrument concerns me more than people flying with less than needed. The original B 747 Jumbo had so many warnings they got rid of more than half of them. Distraction is the thing to avoid when flying. Everglades... changing an undercarriage indicator bulb with 3 crew and no one flying the plane. Nev

Nev, again, we seem to agree... somewhat differently 003_cheezy_grin.gif.c5a94fc2937f61b556d8146a1bc97ef8.gif

At Broken Hill I elected to keep flying and resolve the instrument issue on the ground later (even though a 30 second re-boot is all it took to solve it). Regardless, there was no need for that distraction at a critical time in the flight. It all comes down to proper airmanship.

 

Luckily, my Eurofox is nowhere near a complex as a 747, so my audible alerts are very minimal, and mostly triggered by my own actions (eg. setting & reaching altitude bugs, approaching waypoints, my disabling of the autopilot etc.). Not distracting at all IMHO.

 

As for GPS getting "switched off at will", perhaps I should have more correctly said GNSS. Most of my devices respond to both the American & Russian Glonass constellations of satellites. Three of my devices also position themselves via mobile phone network triangulation (OK for much of my Oz regional flying). And in the unlikely event that the Americans AND Russians agreed to switch them all off, I'll know it immediately when the maps stop tracking. At that point I'll know exactly where I am, and use my magnetic compass (yes I still have one...) to land safely at the nearest airport (along with all the rest of the world's RPT aircraft I would think - heaven forbid!)

 

Your reference to cheap gadgets & proper turn & slip indications is spot-on. Not all flight-attitude "gadgets" can be relied upon & a few of them are little better than a spirit-level glued atop the instrument panel! That is why I am happy with the Dynon, as it has all the flight-parameter sensor data to keep it correct.

 

Now I've really caused thread drift.... sorry 042_hide.gif.f5e8fb1d85d95ffa63d9b5a325bf422e.gif

 

 

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Gliding instructors used to have an airspeed-indicator cover so the student had to fly without ASI . I don't know if they still use it but they sure did on me. As Nev indicated, most people including me flew faster.

 

Flarms are a good example of Nobody's point. Mine often has me turning my head looking to see what the flarm has indicated. I look out more with it than without it.

 

The main problem with using the flarm for RAAus planes is that CASA will want to mandate something much more expensive.

 

 

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I believe that any stall warning device has its merits however, during stall training it is good to be able to switch off the audible warning which gets louder and louder and often stresses out the student as he or she waits for the impending drop out of the sky. A quiet stall is much more relaxing. The same applies to a first time deliberate spin entry.

 

Just my opinion.

 

Alan.

 

 

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It's proven that in an actual emergency audible warnings may often not get noticed at all and may just be a nuisance when you are handling something that has ALL of your attention already (Remember the gorilla in the room) As I've already said I've had the stick shaker at 300' and had to fly it onto the deck with that happening and the F/O having a willy. It's not just ignore and press on and hope for the best .. You have to double check all parameters, sink rate airspeed readings, attitude, flap configuration, power setting, speed brake stowed, glide slope (still on it) and curse the bloke who invented and installed the bloody thing as it's not cancellable, so curse that person too. Would have been even worse had the conditions been IFR or night. Nev

 

 

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Well, in all the years since I started flying (30+) I have never heard anybody say they prefer no audible stall warning. As far as I know, all Jabiru aircraft have a stall warning. I like to hear it squeak just as the wheels touch the ground. If you are flying in even light turbulence, sloppy controls and any buffet due to impending stall could possibly be masked by that turbulence? Still, as long as you're alone when (if) a stall occurs and you're not over my house.

 

 

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the stall, making it hard to "feel how" close you are to a stall. It is why the turn base to final is so deadly.

 

Bullshit. You are not travelling at speed turning onto finals. Its reluctance to bank and over ruddering that kills people.

 

Personally I do not want a stall warning in my plane.

 

On a turbulent day it could be blaring at 80kts.

 

Had that in a spamcan a couple of months ago.

 

Attitude my friend then the occaisional check.

 

Are you even trimmed for correct speed?

 

Modern people do not think one can operate safely without electronic stimulators.

 

I dont want one. If you want one get it right without first.

 

Chas

 

 

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7252. A plane doesn't stall by itself. You have to input the controls for it to happen and the elevator controls the angle of attack of the wing. People only stall in straight and level when practicing stalls, so the first thing to do would be do stalls where they are likely to be done inadvertently. Ie in a turn. Dramatic? Yes it could be and that is why people die. They don't get trained in a real situation so when and if it happens what chance do they have? A stall warning blaring continuously won't help .It may even make things worse. Nev

 

 

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I did my training in the Piper Tomahawk, well known for it's (vicious) stall characteristics. We did climbing and descending turns with a stall, stalls with and without flap and stalls at idle and full throttle. Horrid experience to say the least. Did much the same in the PA28 warrior and if I remember, all we did in the Tobago was a few straight and level stalls which were very benign. Correct, planes don't stall by themselves but a low hour pilot, distracted by heavy circuit traffic, lumpy conditions and a bee in the cabin might get caught. One experience I had a few years ago was when a fellow took me for a ride in a Jabiru, speed back to 60 knots turning final, overshot the centre line and rolled to about 60 degrees to regain the centre line. 60° turn is an increase of 40% on the stall speed. Jabiru stalls at 40 knots full flap, so that turn brought the stall up to 56 knots. Not far from 60 in my books. Maybe I'm just a wooz (woose?) but it was not my idea of fun.

 

 

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Chuck Yeager's opinion on AoA gauges at about 1:00 min

Straight from the master's mouth!!

 

Chuck Yeager's comment re angle of attack indicator:

 

"it's a stupid instrument, if you don't know what your angle of attack is you shouldn't be flying"

 

 

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For the people that mainly use a speed, as a guide, it's a revelation. I know he's a very experienced pilot, but I don't think I agree with him. Whatever your weight or configuration the indicator will adjust for it. In turbulence where you are choosing a speed to optimise controllability with structural loads imposed it will help define the margins you have. Stick stall position doesn't work with horizontal stabiliser working through a large angle where you could trim to one knot above stall speed for weight and still have the stick in the mid position. Jets can get into deep stall effect without buffet. Your elevators can be almost ineffective in a recovery. Nev

 

 

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My Jabiru has a stall-warning device. It is self-energised. And when I built the plane, I moved the trigger a few mm upwards on the wing LE so it would go off sooner. In the air, you can fly around really nose high and slow with the warning sounding.Interestingly, it doesn't sound off on landing. Maybe I'm landing it too fast.

Hi Bruce, the jab LSA stall warning can be made to go off on landing, but like you I find it usually doesn't. A few times it's just started to squeak in the flare, for me.

 

 

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When tricycle undercarriages almost became universal (early 60's), many instructors felt the best technique was to have the nosewheel high on landing with the speed reduced as much as is comfortable. This would bring on the stall warning on most landings. Just a short beep was most common.

 

A spate of accidents occurred later throughout the Industry due to wheelbarrowing which I for one couldn't understand HOW it could be, as generally the skills are less demanding and directional control much better with tricycle U/Cs. It then became clear that people were landing fast and having weight go on the nosewheel and THAT is VERY directionally unstable, if it's overdone. Speed and braking (weight transfer) will cause it which often go together as the end of the runway is a finite length. If there is some tailwind the situation is even worse. Nev

 

 

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  • 4 weeks later...

Most slow speed microlights probably difficult to fit any useful stall warning

 

I built a LRI - lift reserve indicator - and tried it on my Zenair 701 and found that although it indicated readings to help stay in safe attitudes it was not useful in critical parts of flight like landing and t/o where things unravel very quickly.

 

I originally trained in C172 with the strangulated bagpipes style stall warning and found them very vague - years later i was told because those planes were also used for tourist flights the usual practice was to block them up

 

My first GA plane was an old C150 which had the microswitch in the wing and a electromechanical beeper which was very useful and gave intermittent chatter when running at optimum conditions but a continuous tone if you were about to die (flatlining sound)

 

 

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The smaller aircraft that also have low wingloading are very susceptible to speed changes and changing sink rates (they don't have much penetration as some used to call it),that reaction time must be much quicker in gusty conditions than bigger aircraft generally, which have more inertia which may help (but can hinder also if you get well off target). Its likely that trying to scan instruments that often have a lag time is counterintuitive to just flying a little more by the seat of your pants at the final stages of an approach in challenging (gusty) conditions. If you chase airspeed you will overcontrol. You basic reference is ATTITUDE and power by VISUAL reference outside and feel for the power by position of the control or the full power stop if you really are in strife. The airspeed may get just a brief glance to verify that the others are doing what they should.

 

Note What I say here is "general" and don't apply any aspect in isolation when you consider it. It's a mix to bear in mind. You will find your own way of coping best. Nev

 

 

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Re the last bit yes you don't have much margin and the wingspan is large making well coordinated turns a more critical manoeuver at low speeds. I can only think that feeling a thermal is a pretty sensitive thing and you are concentrating on getting the performance, so you are very much in tune with your plane.. Nev

 

 

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