Tom_Waarne
It sure makes a lot of sense. Good calibration is key to good information and safety.
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It sure makes a lot of sense. Good calibration is key to good information and safety.
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The AOA indicator can improve safety if it’s properly integrated, pilots are well-trained, and the display is standardized. Without these, it can become a distraction, adding stress and causing mistakes. Standardization across manufacturers is key to keeping it simple and effective.
Technology only works if you know how to use it and use it properly. To much technology can be more of a distraction than a help. We’re still piling planes into the ground with annoying stall warning horns. I am convinced at this point in GA history training is the best bang for the buck regarding safety.
A whole lot of pilots would ignore it much like they ignore “airspeed indicators”, “slip skid balls” and instructors who tell them over and over to NOT ignore those things. So it may be a marginal savings at best.
Another and simple way of understanding stalls and stalling is to actually teach them, fly all the way into them, let it fully stall and then calmly recover from one, find out you can actually do them without crashing. Different higher tech airplanes have different stalling characteristics. So be shown by someone totally familiar with that aircraft. But before I gave it all up, I had a young flight instructor with me. I slipped on final, I stalled in flight. The kid thought he was going to die in each instance. Or maybe it was just because he was flying with me…hmmm.
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The premise is faulty logic because:
If you are even halfway aware then you already don’t stall/spin into the planet.
If you are unaware then adding another instrument to be unaware of is silly.
Since so many accidents occur when the pilot panics and starts pulling back on the yoke; I don’t think that adding more unused information increases safety.
“The AoA for stall is always the same…” With a clean wing, yes. Add contamination and that AOA is sometimes drastically reduced.
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There is already a requirement for a stall warning device in all aircraft so I really don’t understand what this discussion is about. A stall warning device is an angle of attack indicator. In most of the aircraft I have flown they had a visual reference gage that I really never look at, but I knew the stall warning computer was using it to run a stick shaker or warning horn. The 737 Max had a single angle of attack indicator on it But it crashed due to the angle of attack indicator, not working properly with the computer.
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I agree. Teaching full stalls, incipient stalls and spins, plus recoveries is primary to understanding how a wing develops and loses it’s lift. Teaching approach to stalls is of marginal benefit except to familiarize someone with the sluggish control feel and abnormally nose high attitude. If AOA is taught ab initio then a student will refer to this instrument instinctively throughout their flying careers. BTW, why is there always a little bit of string on the nose of gliders?
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Accident mitigation is really a systems engineering problem, including operating environment, sensor capabilities, maneuver considerations, human factors in display, pilot skills, and so much more. To ignore this complexity and grab onto an overly simplistic “solution” – requiring AOA displays – is, sadly, nothing more than virtue signaling. Virtue signaling is when a complex situation is reduced ad absurdum to something that sounds good, feels good, is catchy, and will impress the unknowledgeable.
Research of literally thousands of NTSB reports shows that base to final loss of control accidents are as likely as not to be botched steep turns, similar to botched 360° turns at altitude. These low angle of attack, ball-centered loss of control events will not trigger AOA sensors.
There are also numerous stories at flight instructor conferences on the current low quality of pilot and CFI applicants. Giving marginally qualified applicants one more gadget to ignore in extremis is unlikely to solve problems. (First draft had an editing error, sorry)
The opportunities for safety improvement are real and should be pursued. Advocating AOA devices, is however, virtue signaling rather than addressing the real underlying problems.
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I’m interested in data showing “the current low quality of pilot and CFI applicants”. Can you provide some links to this data?
Yes, let’s add another expensive device to all aircraft. If pilots can’t keep their planes trimmed to a safe airspeed, maybe they can learn how to use an AoA gauge. Apparently, a lot of them can’t read fuel gauges or weather reports. It’ll be great.
The AOA indicator must be installed correctly, or, you will get erroneous information. Oh geeh,
, I wonder what that looks like?
My Maule has a kind of AOA in the form of a leading edge tab that operates a microswitch that turns a light on the panel about 5 mph before a stall. The difference is that it’s an on-off sensor with no in-betweens. Most AOA devices use a similar mechanical vane operated by air pressure from the relative wind but they control a variable resistor (or similar device) that shows the angle of the wing over a range in different colors. They have to be calibrated properly to be accurate and they can drift out of calibration over time. I think an AOA indicator is good for inexperienced pilots or those who aren’t familiar with the stall characteristics of a new (to them) airplane. I’ve owned and flown my Maule for 26 years and over 1,800 hours and have done a lot of actual stall training so I know what an imminent stall or real stall feels like and how to recover based on the feel of the controls. Adding a AOA indicator in my Maule wouldn’t make sense and would cost about $5,000. It might also give me a false indication if there was any ice buildup on the wing or wind vane. I agree that the manufacturer’s airspeed table isn’t the best way to detect the proximity of a stall. Modifications like my vortex generators alter the airplane’s stall characteristics. It’s better to practice stalls in the full range of flap, CG and bank configurations and create a calibration card for your specific airplane. That’s what McCall Mountain Canyon Flying Seminars had me do in my airplane when I did refresher training with them in 2016.
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You nailed it Andrew. So easy for the government and those who spent their life in it to just say “throw money at the problem”. It would be a complete waste of money for you to have to add this system to your plane. Once size fits all is not the answer, plus I get tired of people telling me how to spend my money. Been flying 49 years in everything from helicopters to triple 7’s and have not seen the need for this. Fly the plane, keep SA, and always leave a way out.
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Hmmm. I honestly doubt that installing an AOA system is the solution for sloppy flying and ignorance of training. The basics, power, pitch and airspeed seem to have been forgotten. Basic stall warning systems seem to get ignored. How the plane “feels” seems now forgotten as well. I think the cost of this enhancement is not worth the minimal effect, in my opinion, it will have on preventing accidents. I’ve seen AOA indications ignored in the cockpit too. I agree that the conditions that AOA is useful is only in clean wing conditions. Calibrating AOA to each aircraft is also an important factor.
If anybody actually read the document they might notice it is targeting transport category aircraft. Typically these are much more sophisticated airplanes that require type ratings and structured training. There were so many things wrong in that Colgan air accident and what we ended up with was a1500hr requirement before you were permitted to expose your passengers to a stall LOC accident.
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I read the SAIB to say that the FAA recommends AOA indicators in all aircraft that operate under parts 121, 135, 91, 91 subpart K, experimental aircraft and all aircraft certificated under part 23 - not just transport aircraft. That’s what the final paragraph says even though the examples are for transport category aircraft.
All I’m saying is that pilot training and experience in the aircraft are factors that the SAIB omits and should consider. All of the new technology in a GA aircraft increases cost in fairly large jumps. An AOA indicator adds about $5,000 in purchase and installation. That trend is how we get to a Cirrus SR22 with a base price of over $800,000 - way out of reach for most GA pilots. My 1986 Maule cost me $51,175 in 1998. Technology is good but too much of it can make flying impossible except for the wealthy. I don’t think that’s where aviation should end up. In my opinion training has a more beneficial effect on safety than throwing new technology at inexperienced pilots.
Many who eschew AoA have never flown with a true AoA indicator. A true unit utilizes a vane to derive the information. Many units on the market are derivative AoA thus requiring calibration. They are simply air pressure units and their calibration requirements make them suspect. Also because they are dependent upon air pressure I recently heard of an aircraft having the door pop open on takeoff caused erroneous static pressure inputs, and creating bad AoA information.
Having flown a true AoA in line operations on transport aircraft I became aware of how many times the aircraft was heavier than the W&B paper work. The result was better and more consistent landings. The other thing that amazed me was how much simple rain affected lift reserve. A true AoA unit does make for better and safer flying.
I did read the document. While it opens with an example from air transport, the body of the bulletin is obviously targeted at general aviation. The devices/products mentioned are the things you’ll find in booths at Oshkosh. The transport aircraft generally don’t have bolt-on solutions available (and they tend to have sophisticated AOA systems in the original design anyway). The modification/retrofit market is definitely GA. So that is the only practical target audience for a plea to equip.
I’m like Adnrew. I have lots of hours and lots of years flying my personal airplane, and I know it pretty well. I don’t think an AOA indicator would help me fly my airplane. In all my years, I have once ONCE been surprised by the stall indication horn, and it helped. That was during a climb at high altitude, where I had been pulling back more and more on the controls without realizing it, due to terrain in the area. Happily, I reacted correctly to the indication. Despite the terrain, I lowered the nose and increased speed and restored my climb performance. It was not an intuitive response. It was trained behavior.
Devices and equipment are nice, but they aren’t the answer. You can really only buy safety at the store that sells pilot training.
Here we go again, the government “recommending” a solution to a non-existent problem. The recommendation will soon turn into a requirement, to the pleasure of AOA indicator makers. When flown by real pilots, all aircraft give clear indications of imminent stall, if the pilot knows what to look for. On fabric-covered aircraft, you can literally feel the onset in the stick through slight vibration when the line of separation creeps forward from the trailing edge. A yoke or stick becomes “mushy”. Back in the day when pilots first learned to fly in ragwing gliders and taildraggers, they developed a feel for such things. A small piece of yarn taped on the outside of the canopy was another great flight instrument that cost nearly nothing.
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Raf is spot on. I have flown aircraft with a number of AOA systems since the 1970s. These are next to useless without aircraft and activity oriented training. I was particularly impressed with the practices and training provided by Ransome Airlines for the use of the DHC-7 AOA while conducting the STOL 7.5 degree approaches.
Like Raf, I am disappointed by the lack of consistency in both the siting and display of these. useful tools.
Will the units come with a healthy dose of airmanship? If not, well…
On aircraft like the 737NG, AOA display on the PFD is available as an airline option. Most airlines do not pay to have this turned on.
Like all these great ideas it needs to be thought through carefully, as training and awareness must be paired with the additional information. Personally I mostly stay far away from stall speed, flying my turbo Mooney between Livermore CA and the San Juan Islands. AOA would be useful once established on short final, as Mooneys don’t forgive landing fast. It would have also helped last year landing in Auburn WA, in the pattern with 3 slow flying 172’s. But I would never need AOA for base to final safety as airspeed and turn & bank indicator are my focus.
Thus, I do not believe AOA’s for all is the best cost-benefit choice.
That’s a warning, which is common.
The question is what the PF does about the warning sounding/vibrating.
The question is how would a pilot use the AOA indication, given there already is a stall warning sound/vibration.
Perhaps quickly check airspeed - oh, already can do that.
In the case of malfunction of airspeed system pilot could look in the clutter to check AOA value against coloured ranges. Then get pitch correct and hold it and power.
That’s what a QF crew did when pitot-static system of a B707 iced from moist air driven high by wind deflecting off mountains. No AOA indicator on that airplane.
Original B737 now has amber pitot heat lights hooked to master caution, IIRC. (Originally had green lights showing current was flowing through each heater, but being on aft part of overhead panel of a two-pilot airplane a dark one could be missed.)
Yes, better knowledge of airspeed and stall, especially effect of bank angle on required lift thus stall speed, would be helpful.
(Boeing airliners have both a sound and vibration of control columns. (Perhaps sound can be cancelled to help think, vibration is by an off-centre weight spun by motor strapped to the column, at least on narrow body airplanes.
I don’t remember DC8-7x from a flight test in which we nibbled at stick shaker to check engine stability, had more on my mind afterward than learning details of that airplane.)
My flight experience is GA, mainly experimental aircraft. Some airplanes have very nasty stall characteristics, with very little warning (Lancair 4, etc); good luck getting anyone to teach you stalls in those planes. I fly with a AOA but admit that I don’t use it enough. Last Summer while making a steep bank, on “speed”, downwind to base at a mountainous airport, the AOA popped up. It got my attention and I made the necessary corrections. Maybe Navy carrier pilots should chime in. I can’t speak to commercial aviation but wasn’t there a tragic accident some years ago (?Air France) over the Atlantic where the pilots rode a stall from ?25,000 feet into the ocean.
Analog AOA - Specifically FAA approved for ALL GA aircraft with simple logbook entry. $389 + 2-3 hours installation. Panel Mount or Glare Shield Mount. Lift Management, LLC (https://lift-mgt.com)
Not just a stall warning device. Manage lift at a glance, spot trends instantly. More intuitive than any digital display. Use it to train your seat of the pants feel for your airplane. On take-off, gauge sufficient lift to get safely into ground effect, safely get the most performance you paid for from your aircraft in marginal situations.
The AOA display is the final output to all other control inputs. It doesn’t tell you how to fly, you fly the aircraft and make it display the results you want. Almost all aircraft have an AOA indicator already called a stall warning.
I’m not sure more stall recovery training or spin training would help. Stall and spin prevention through thorough training including sim training would lower the accident rate. That and 100% less “cowboy” videos on YouTube encouraging edge of the envelope flying to postcard pilots.
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Until and unless training airplanes have AoA-I installed (addressed by the SAIB) and flight instructors know how teach their use, the FAA is peeing up the proverbial rope. I read the complete SAIB. Teaching instructors was not directly addressed. Again.
Back in 2014 the General Aviation Joint Steering Committee released a report stating installing AoA could help in reducing LOC accidents. They’re right but they did not directly address training airplanes or instructor training.
That’s a shift I don’t see happening soon. Flight schools will not adopt adding expensive AoA indicators and worse flight instructors won’t buy in for all the questionable reasons stated above.
Very sad.
Obviously not “needed”. However, AOAs everywhere has always seemed like a no-brainer to me, as the vast majority of US military fixed wing aircraft have them - for a reason. Birds have them too, connected directly to their nervous systems. This is tough for a human inside an aircraft, therefore we have AOAs.
It is about time. Angle of attack is the only indication that tells the pilot that the wing is generating lift, up to the Critical Angle of Attack when stall occurs. This is regardless of airspeed, angle of bank or G-load. It is the primary instrument for carrier landings in the US Navy. One hull loss that would have been prevented is Air France 447, and there are many more examples.
I’m have the calibration video in my YouTube https://youtu.be/nwsTaxpHoag?si=kRMXgyNFt4S96c0V
See my AoA training videos at Angle of Attack Training - Maui Flight Academy
I strongly disagree with mandating this device. I currently fly a plane equipped with one. I find it to be a useless distraction from other inputs to my situational awareness. What other inputs? Speaking only of VFR flight: Airspeed, attitude (bank and pitch), height above ground/ runway, and “feel”. Real airmanship means having situational awareness based on these inputs. Why does the AoA not help me? For one thing, it’s highly derived, meaning that it is not a direct input, but consists of multiple aerodynamic inputs, further processed, to portray AoA. These multiple stages of processing do not give me confidence. Is the aerodynamic part thing calibrated correctly? Is the electrical stage calibrated correctly? Beyond this, the actual use of the instrument is awkward and badly conflicts with the my primary inputs of ASI, and situational awareness. An audio stall warning, as on Cessnas for decades seems far better. That doesn’t compete with your visual inputs of ASI and attitude. What is wrong with that, requiring this gadget? Mandating this is a terrible idea, forcing a major expense, without any proven benefit.[quote=“system, post:1, topic:46675, full:true, username:system”]
A prominent proponent of angle of attack (AoA) indicators is applauding the FAA for recommending they be installed in all airplanes. The agency published a special airworthiness information bulletin (SAIB) recommending AOA systems be installed as standard equipment in new airplanes and retrofitted in the existing fleet. The full document is reprinted below. "Outstanding step forward by the FAA, recognizing the importance of AoA systems in keeping the pilot better informed on where the wing is operating relative to the stall," said Paul Dye, a serial homebuilder and former NASA Flight Director who has been promoting the tech for years. "Increasing the use of AoA systems - and training pilots to use them – will never prevent all accidents. But it is a definite step in the direction of reducing the number of loss of control mishaps.
An AOA indicator would not be needed if student pilots were taught to recover from stalls and full spins. Spin recovery used to be part of the required training years ago, but it was removed because training aircraft did not have speed breaks to prevent wing separation. Glider pilots still train for spins. Recovery is simple and being able to do it instinctively adds greatly to the student’s flying confidence. Ability able to instantly identify a stall is an important flying skill and it should not depend on an instrument. Power pilots who want to learn spin recovery can do it by taking a few glider lessons. But, watch out! Spins are great fun and you might become an addict!
The string is the simplest and least expensive of all aircraft instruments. So long as the string is vertical, the glider is flying coordinated so it helps the pilot to fly coordinated turns. It also serves as a stall indicator because, if it goes limp, the stall has caused reduced air flow over the nose.
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Nothing but whitewash. When I look at the fatal GA accidents in the last few months, it’s the pilot who makes bad decisions to take their family into known IFR conditions without the qualifications or skill required. An AOA would have just told them “you are about to die”. Case in point, two fatal accidents just one week ago with non-instrument rated pilots killing themselves and their family by purposfully flying into IMC conditions without an instrument rating. You can’t fix stupid.
I thought maybe your comment was not serious, but it is hard to know because many power pilots have never been near a glider. Just about every non-pilot who came to the gliderport with me asked about the string. I do believe that some glider training would help power pilots with airmanship and being more sensitive to what is happening to the airplane in different conditions. Interestingly, glider training starts with learning to follow the tow plane correctly, which is really formation flying - an advanced flying skill.