The Holy Micro\u2019s Absolute AoA indicator is a lifesaver because it ignores airspeed and focuses on the only thing that actually causes a stall: the Angle of Attack (AoA)<\/strong>. In a turn, your “Stall Speed” is a moving target, but your Critical AoA<\/strong> is fixed. All the Pilot Operating Handbooks (POH) indicate the Stall Speeds for different Bank Angles. The pilots are expected to remember these numbers during the flight regime. The below table show the Stall Speeds at 00 Bank Angle and 600<\/sup> Bank Angle for Max Gross Weight, clean config.<\/p>\n\n\n\n Comparison: Level Flight vs. 60\u00b0 Bank<\/strong> Summary<\/strong> The Absolute AoA provides an instant, “real-time” visual and audio warning that an airspeed indicator\u2014which doesn’t know you are banking\u2014simply cannot give.<\/strong><\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" How to Mitigate Accelerated Stall Risks in High-Bank Maneuvers via Absolute Angle of Attack Lift Reserve Indication and Changing Frequency and Pulse Rates of the Tones? Why an AoA Indicator is Safer than an Airspeed Indicator during the Turn to Final? Beyond Airspeed:How the Holy Micro\u2019s Absolute AoA Predicts and Prevents Accelerated Stalls. Keep It […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-379","post","type-post","status-publish","format-standard","hentry","category-skyvoice-alert"],"yoast_head":"\n
Here we use our Chevron Presentation as a reference to expand on the above point.<\/p>\n\n\n\n\n
The Holy Micro system is calibrated so that the Blue Donut represents your “on-speed” approach.
\u25cf The Math<\/strong>: This corresponds to 1.3 times the Stall Speed (V-stall)<\/strong>.
\u25cf The Reserve:<\/strong> When you are “in the donut,” you have exactly 40% Lift Reserve<\/strong> remaining.
\u25cf The Benefit:<\/strong> On the base leg, as long as you see that Blue Donut<\/strong>, you know you have a solid safety cushion.<\/li>\n\n\n\n
In a banked turn, the airplane feels “heavier” due to G-loading<\/strong>. To maintain altitude, you must pull back on the yoke, which increases your Angle of Attack<\/strong>.
\u25cf Airspeed Indicator:<\/strong> Might still show 70 knots (your normal approach speed), making you feel safe.
\u25cf Holy Micro AoA:<\/strong> As you steepen the bank and pull back, the indicator will move away from the Blue Donut<\/strong> towards the Red immediately. It shows you are “spending” your 40% reserve to maintain altitude in the turn.<\/li>\n<\/ol>\n\n\n\nType of Aircraft<\/strong><\/td> Stall Speed at 00<\/sup> Bank Angle<\/strong><\/td> Stall Speed at 600<\/sup> Bank Angle<\/strong><\/td> Remarks<\/strong><\/td><\/tr> Cessna 172<\/strong><\/td> 42 KIAS<\/strong><\/td> 59 KIAS<\/strong><\/td> Stall Speed at 600<\/sup> Bank Angle is more than the Approach Speed<\/strong><\/td><\/tr> Cessna 441<\/strong><\/td> 89 KIAS<\/strong><\/td> 128 KIAS<\/strong><\/td> Stall Speed at 600<\/sup> Bank Angle is more than the Approach Speed<\/strong><\/td><\/tr> Piper Cherokee P28<\/strong><\/td> 55 KIAS<\/strong><\/td> 75 KIAS<\/strong><\/td> Stall Speed at 60\u00b0<\/sup> Bank Angle is more than the Approach Speed<\/strong><\/td><\/tr> Beechcraft Bonanza A36<\/strong><\/td> 62 KIAS<\/strong><\/td> 87 KIAS<\/strong><\/td> Stall Speed at 600<\/sup> Bank Angle is more than the Approach Speed<\/strong><\/td><\/tr> Cirrus SR22<\/strong><\/td> 70 KIAS<\/strong><\/td> 99 KIAS<\/strong><\/td> Stall Speed at 600<\/sup> Bank Angle is more than the Approach Speed<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n \n
The Red Triangle on the top represents the angle just below the Critical Angle of Attack.<\/strong>
\u25cf The Math<\/strong>: Beyond this angle of attack Lift Reserve is 0%.<\/strong>
\u25cf The Danger:<\/strong> If you are in a steep base-to-final turn (e.g., 45\u00b0 or 60\u00b0 bank) and you pull until the
indicator hits the top Red Triangle<\/strong>, you will stall\u2014even if your airspeed is well above the “normal” 1-G stall speed. This is an accelerated stall<\/strong><\/li>\n<\/ol>\n\n\n\n
Assuming you are flying at a constant 75 knots<\/strong> (your 1.3 V-stall speed)<\/p>\n\n\n\nFlight
Condition<\/strong><\/td>Airspeed<\/strong><\/td> Absolute AoA
Indication<\/strong><\/td>Absolute AoA
Tone<\/strong><\/td>Lift<\/strong>
Reserve<\/strong><\/td><\/tr>Level Flight<\/strong><\/td> 75 KIAS<\/strong><\/td> Blue Donut<\/strong><\/td> Solid Tone<\/strong><\/td> 40%<\/strong><\/td><\/tr> 30\u00b0 Bank<\/strong><\/td> 75 KIAS<\/strong><\/td> Top half of Blue<\/strong> Donut and
Slanted Red Lines<\/strong><\/td>1600 Hz Tone with Low Pulse Rate<\/strong><\/td> ~28%<\/strong><\/td><\/tr> 45\u00b0 Bank<\/strong><\/td> 75 KIAS<\/strong><\/td> Slanted Red Lines and Solid Red Triangle<\/strong><\/td> 1600 Hz Tone with Medium Pulse Rate<\/strong><\/td> ~12%<\/strong><\/td><\/tr> 60\u00b0 Bank<\/strong><\/td> 75 KIAS<\/strong><\/td> Solid Red Triangle<\/strong><\/td> 1600 Hz Tone with Very High Pulse Rate<\/strong><\/td> 1%<\/strong>
(STALL)<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
The Holy Micro\u2019s Absolute AoA<\/strong> translates complex inverse-square physics into a simple visual: Keep it in the Blue. If you see the display moving from the Blue Donut towards the Red during your base-to-final turn, the wing is telling you that your 40% “budget” is disappearing. To “Keep it in the Blue<\/strong>,” you must reduce the Angle of Attack<\/strong> by relaxing back pressure (pitching down) or shallowing the bank<\/strong>. While adding power helps maintain altitude or airspeed, reducing the wing’s “load” is the most immediate way to recover your Lift Reserve. <\/p>\n\n\n\n