stall warning - audio buzzer

[johnm]

I remember the 'audio stall warning' with GA planes

 

I'd be interested to know of there are any ultralights with them - I can't imagine it is a common installation ?

 

I prefer silence than that annoying stall warning - what say you ? - or what advantage is there in having an audio stall warning (if any) ?

 

 

[kodiak74]

"I prefer silence" - like that eternal kind of silence you get after a low altitude stall without any warning ?

 

 

[Roundsounds]

"I prefer silence" - like that eternal kind of silence you get after a low altitude stall without any warning ?

If your sole means of avoiding a low altitude stall is an audible stall warning, I suggest you seek further stall awareness training.

 

 

[kodiak74]

If your sole means of avoiding a low altitude stall is an audible stall warning, I suggest you seek further stall awareness training.

Hah ! - I should have realised there was an ambush waiting on that one. But seriously - anything that improves situational awareness (& safety) is good to have. There could be any number of scenarios where attention could be diverted leading to the aircraft getting into an undesirable state & approaches stall. Depending on the aircraft you may get some physical warning, or maybe non at all, but with a buzzer you get a audible prompt to get things under control.

 

 

[Roundsounds]

Hah ! - I should have realised there was an ambush waiting on that one. But seriously - anything that improves situational awareness (& safety) is good to have. There could be any number of scenarios where attention could be diverted leading to the aircraft getting into an undesirable state & approaches stall. Depending on the aircraft you may get some physical warning, or maybe non at all, but with a buzzer you get a audible prompt to get things under control.

Still firmly believe reliance upon stall warning devices to be dangerous. If your SA is poor enough to not know you're getting close to stalling you do need upskilling. Remember - Aviate, Navigate etc - nothing takes precedence over flying the aircraft. Of course the highest degree of risk would be when seriously loaded up during a forced landing and if you've secured the aircraft correctly most stall warnings will not function when you really need them. (ie: master switch OFF)

The best way to develop your ability to detect in "impending stall" is to gain an aerobatic flight activity endorsement.... and use it.

 

 

[Nobody]

The requirement for certification is copied from 14 CFR 23.207 below. The 5 knots worth of warning is hard to achieve through aerodynamic methods/buffeting alone and so most aircraft need some audible warning.

 

Roundsounds, over 100 years after the first flight pilots continue to crash aircraft and cause injury and death by stalling. Significant research from the USA has shown that Angle of attack indicators, with audiable warnings, significantly reduce the rate of loss of control incidents, to the extent that the FAA has relaxed the rules requiring engineering approval to fit them to existing aircraft to encourage wider adoption.

 

a) There must be a clear and distinctive stall warning, with the flaps and landing gear in any normal position, in straight and turning flight.

(b) The stall warning may be furnished either through the inherent aerodynamic qualities of the airplane or by a device that will give clearly distinguishable indications under expected conditions of flight. However, a visual stall warning device that requires the attention of the crew within the cockpit is not acceptable by itself.

 

© During the stall tests required by § 23.201(b) and § 23.203(a)(1), the stall warning must begin at a speed exceeding the stalling speed by a margin of not less than 5 knots and must continue until the stall occurs.

 

(d) When following procedures furnished in accordance with § 23.1585, the stall warning must not occur during a takeoff with all engines operating, a takeoff continued with one engine inoperative, or during an approach to landing.

 

(e) During the stall tests required by § 23.203(a)(2), the stall warning must begin sufficiently in advance of the stall for the stall to be averted by pilot action taken after the stall warning first occurs.

 

(f) For acrobatic category airplanes, an artificial stall warning may be mutable, provided that it is armed automatically during takeoff and rearmed automatically in the approach configuration.

[kgwilson]

Stall warnings are good if you happen to nod off while on short final & pull back a bit too much. The resultant sharp wakeup squawk will probably mean you crash a couple of milliseconds later than you would have if you didn't have a stall warning. Tongue now out of cheek. I flew with them in GA aircraft & most seem to be set at about 10 knots above stall. Probably good for a new pilot but there are times when they are a nuisance like when you have to fly at full power just above stall & turn to clear a bloody great mountain in front of the runway you are taking off from. It seems to unnerve passengers when you tell them what the noise is.

 

 

[kodiak74]

Umm, a lot of GA aircraft (ie Cessna's) use a pressure based system for the stall warning - no electrics required. From a quick internet search, the stall switch on the Beech 18 is hot wired (bypasses master) so that it will work always. Given how important a functioning stall warning indicator is, I would suspect that this would be the case on a lot of aircraft. But I don't know that for sure, so it is up to each pilot to know how the systems on their aircraft operate. Putting a blanket statement like "most stall warnings will not function when you really need them" in a public forum is downright irresponsible. By all means highlight aircraft types where this is the case, but a generalisation like that helps no-one.

 

Aerobatic endorsement - seriously ? - basic stalls and recovery are covered in the GFPT - the real question is how often do we practice them. The one thing that would make me think about doing the Aerobatic endorsement would be spin recovery training - but thats a different discussion.

 

Just to set the record straight - I'm not saying that one should rely solely on the stall warning indicator, its part of the sensory inputs (like stall buffet, instruments and gauges, and wind/engine sound) that you use to build up your awareness of your situation. Given a stall is not a good thing to have happen, and little friendly reminder from time to time is a good thing. Likewise everyone benefits from stall training and improved handling skills,etc.

 

 

[Yenn]

I have a Cessna stall warning in my Corby, it is a small trumpet like funnel, activated by low pressure. I never got around to finding the correct spot for the sensor tube to be mounted so it doasn't work. I can fly at about 5 knots above the stall by the feel of the controls, so it is unnecessary. How many airliners have crashed with the sound of the stall warning screaming away in the cockpit voice recorder and the pilot not releasing stick back pressurs?

 

 

[Roundsounds]

Umm, a lot of GA aircraft (ie Cessna's) use a pressure based system for the stall warning - no electrics required. From a quick internet search, the stall switch on the Beech 18 is hot wired (bypasses master) so that it will work always. Given how important a functioning stall warning indicator is, I would suspect that this would be the case on a lot of aircraft. But I don't know that for sure, so it is up to each pilot to know how the systems on their aircraft operate. Putting a blanket statement like "most stall warnings will not function when you really need them" in a public forum is downright irresponsible. By all means highlight aircraft types where this is the case, but a generalisation like that helps no-one.Aerobatic endorsement - seriously ? - basic stalls and recovery are covered in the GFPT - the real question is how often do we practice them. The one thing that would make me think about doing the Aerobatic endorsement would be spin recovery training - but thats a different discussion.

 

Just to set the record straight - I'm not saying that one should rely solely on the stall warning indicator, its part of the sensory inputs (like stall buffet, instruments and gauges, and wind/engine sound) that you use to build up your awareness of your situation. Given a stall is not a good thing to have happen, and little friendly reminder from time to time is a good thing. Likewise everyone benefits from stall training and improved handling skills,etc.

I have operated and instructed in a large variety of aircraft types and assure you the majority require the master switch to be on for them to operate (the pre-flight inspection soon determines that). I hope my "blanket statement" concerning stall warning devices result in readers determining the situation in the various aircraft types they operate. I have a couple of hundred hours in a Beech D18S, the type could safely operate without any stall warning device as the pre-stall buffet is quite pronounced.

 

Stall recovery training is no where near as important as learning the symptoms leading up to a stall, so recovery can be initiated before the stall. These symptoms/cues vary between aircraft types and include placement of the flight controls as they control angle of attack and slip/skid. To say aerobatics are of lesser value than the spin recovery training is an ill-informed take on aerobatics. You spend a significant portion of time at/near/beyond the critical angle in a number of manoeuvres. Spin recovery training is of little use to a pilot who unintentionally enters a spin at or below circuit height. A pilot who allows an aircraft to enter a spin in the circuit is unlikely to have the skills to recover before hitting the ground. Again, learning to recognise an impending spin and initiating recovery before it develops is far more important than spin recovery.

 

I'm not saying stall warning devices are a bad thing, they are way down the list when it comes to avoiding an unintentional stall. If you consider the stall training delivered during abinitio training is adequate, you really should find a good instructor (current aerobatic pilot) to do further training in the types you operate and with the C of G in the range you would normally operate at.

 

I appologise for ranting, but the stall / spin accident rate would reduce significantly if pilots received proper training.

 

 

[kodiak74]

No apologies required - its all a matter of perspective. You clearly have the good fortune to spend more time in the cockpit than some of us mere mortals. For those of us who haven't had the training (either quality or quantity), or hours of experience, we will take all the help we can get ! I think the crux of our differing arguments is that your position is to make every pilot "stall safe", which we can all agree on, however that takes time and money that may not be available to all. My point is if the plane is "stall safe" we cover all skill levels of pilot, and have an additional safety warning system for when we forget our training.

 

Yenn - Having watched most of the Air Crash Investigators there was only one deep stall crash I can remember - BEA 548 - and that was fitted with a stick shaker system, but I'm sure there were other alarms going off as well. Anyway the amount of alerts and warnings on airlines puts most/all GA aircraft to shame, and I wouldn't expect anyone to be able to fly one of those by feel at 5 knots above stall without them!

 

 

[frank marriott]

it is up to each pilot to know how the systems on their aircraft operate

Very relevant point - not just related to a stall warning device.

 

 

[Bruce Tuncks]

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.

 

 

[johnm]

thanks BT - that's the first ultralight I've heard of with a stall warning device ............... what %age have them I do not know ?

 

if a stall warning device is seen as such a critical thing (for) - why do some planes not have them (against)

 

 

[facthunter]

The standard method of stall recovery that is generally used in training results in too great a height loss to save you on final. Yes angle of attack related Indicators are essential on big stuff. Regardless of your configuration, they indicate the situation. Warnings can be very distracting if they are in error, and a bit ineffective if set too high. I've had a stick shaker activation that was erroneous at a few hundred feet on a jet, and It's not fun, I can assure you. Failed warnings are a real concern even though they might be rare.

 

Stalling is not a speed and it is an angle of attack thing. The pilot determines the AoA with the elevators and pulling back is fairly instinctive when the nose drops. People ARE "assisting' the turn with unbalanced rudder . Better training is needed rather than insist on an audio stall warning. You original straight and level should have been from stall speed (almost) to above cruising with trim and "feel " of controls emphasised. SLOW flying is when you concentrate more as the margins are reduced. Less responsive controls should be noticed long before you are stalled in "our" type of aircraft. People are generally $#1t scared of stalling or flying slow. That's reasonable as you should concentrate but knowing more about it is the answer. Most planes that stall have stall warning devices fitted. Don't get too worked up about airliners being mishandled as it's not got a lot to do with what's happening with simple conventional sport basic planes.

 

Some don't embrace the Stick stall position concept fully but the principle is there to be understood. Aeroplanes don't stall without pilots doing it to them, unless something untoward is going on like out of balance, mistrimmed icing etc. Nev

 

 

[Roundsounds]

The standard method of stall recovery that is generally used in training results in too great a height loss to save you on final. Yes angle of attack related Indicators are essential on big stuff. Regardless of your configuration, they indicate the situation. Warnings can be very distracting if they are in error, and a bit ineffective if set too high. I've had a stick shaker activation that was erroneous at a few hundred feet on a jet, and It's not fun, I can assure you. Failed warnings are a real concern even though they might be rare.Stalling is not a speed and it is an angle of attack thing. The pilot determines the AoA with the elevators and pulling back is fairly instinctive when the nose drops. People ARE "assisting' the turn with unbalanced rudder . Better training is needed rather than insist on an audio stall warning. You original straight and level should have been from stall speed (almost) to above cruising with trim and "feel " of controls emphasised. SLOW flying is when you concentrate more as the margins are reduced. Less responsive controls should be noticed long before you are stalled in "our" type of aircraft. People are generally $#1t scared of stalling or flying slow. That's reasonable as you should concentrate but knowing more about it is the answer. Most planes that stall have stall warning devices fitted. Don't get too worked up about airliners being mishandled as it's not got a lot to do with what's happening with simple conventional sport basic planes.

Some don't embrace the Stick stall position concept fully but the principle is there to be understood. Aeroplanes don't stall without pilots doing it to them, unless something untoward is going on like out of balance, mistrimmed icing etc. Nev

Well said Nev!

It'd also suggest very few low level stall/spin accidents occur with idle power, wings level and in balance - so why train it only in that config'? I think you've hit the nail on the head - a lot of instructors are wary of stalling.

 

 

[Downunder]

thanks BT - that's the first ultralight I've heard of with a stall warning device ............... what %age have them I do not know ?if a stall warning device is seen as such a critical thing (for) - why do some planes not have them (against)

Seen one on a Foxbat and possibly a Sportstar.......

 

 

[Flying Officer Kite]

Seen one on a Foxbat and possibly a Sportstar.......

... and a Jabiru.

 

 

[facthunter]

Dunno why you would want one on a Foxbat. Nev

 

 

[Bruce Tuncks]

Good stuff Nev. I demonstrated your point with a control-line model when I was a kid. It had too sharp a leading edge... vertical dive, up elevator, high speed rotation, high-speed stall. Splat into the ground in a level attitude.

 

On the Jabiru, the angle of attack warning ( I agree we shouldn't call them stall warning) thing is purely pneumatic, it makes a harsh sound when the actuator comes under suction. Nothing much to fail.

 

At this time , the attitude is so nose high that I fail to see how you could stall this Jabiru inadvertently, at least with the wings fairly level and without a big elevator input.

 

You are looking at the sky and the controls are sluggish but all still working in the correct sense.

 

Gliders do not have AoA-warning devices because they spend a lot of time near the stall when thermalling. Turning tight, 45 degrees of bank and right down near the stall. You would think that this is a recipe for spinning but its quite safe. In 50 years I have never seen a thermalling glider enter a spin.

 

 

[Flying Officer Kite]

Dunno why you would want one on a Foxbat. Nev

Agreed - there isn't one on either of the two Foxies I'm training on. Wasn't easy to induce a stall when the recovery procedure was being covered, and anyway the "seat of the pants" alert provided ample warning before it happened!

 

 

[djpacro]

... It'd also suggest very few low level stall/spin accidents occur with idle power, wings level and in balance - so why train it only in that config'? ....

Seen the new advanced stalling and incipient spin elements in Part 61 MOS?

 

Well said Nev! ...I think you've hit the nail on the head - a lot of instructors are wary of stalling.

Yes indeed, even more so with the new Part 61. My opinion is that the advanced stalling/incipient spin exercises require an instructor with a spin training endorsement (consider also CASA's new definition of aerobatics).

[dsam]

Any Dynon Skyview equipped aircraft (when using their pitot tube) shows AoA on the display at all times. It also gives an audible & verbal warning of imminent stall (and excessive airspeed too, BTW).

 

Excellent situational awareness is made much easier with modern instrumentation, but there is no substitute for basic stick & rudder skills, and a natural "seat of the pants" awareness of flight parameters (in VMC). IMC is another story, but not part of RA-Aus aircraft operations.

 

 

[Roundsounds]

Any Dynon Skyview equipped aircraft (when using their pitot tube) shows AoA on the display at all times. It also gives an audible & verbal warning of imminent stall (and excessive airspeed too, BTW). Excellent situational awareness is made much easier with modern instrumentation, but there is no substitute for basic stick & rudder skills, and a natural "seat of the pants" awareness of flight parameters (in VMC). IMC is another story, but not part of RA-Aus aircraft operations.

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.

 

 

[Roundsounds]

Seen the new advanced stalling and incipient spin elements in Part 61 MOS?Yes indeed, even more so with the new Part 61. My opinion is that the advanced stalling/incipient spin exercises require an instructor with a spin training endorsement (consider also CASA's new definition of aerobatics).

It's certainly an improvement over the old Day VFR Syllabus, but there will be very few instructors with the skills to deliver the training as per the MOS. Additionally the same skills problem exists with instructor trainers and a lack of suitable aircraft to deliver the training.