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UPSET DEFINITION AND CAUSES

Updated: Apr 12, 2022

The study groups have found that "Upset" is a precursor to most of LOC-I accidents. Today, we'll go through "Upset".

First, Let’s take a quick look at “Upset” meaning from the Cambridge dictionary… 1. to make someone worried, unhappy, or angry: (For Airplane Upset, we’re not talking about ‘human’ or pilots ) 2. to change the usual or expected state or order of something, especially in a way that stops it from happening or working: (Yes, we’re looking at an “Airplane” state )


ICAO Doc10011

An airplane upset is defined as an airplane in flight unintentionally exceeding the parameters normally experienced in line operations or training.

There are two keywords in the definition; “Unintentionally” deviation of “Normal Parameter”.

Upset is normally defined by the existence of at least one of the following parameters:

a) pitch attitude greater than 25 degrees, nose up; or

b) pitch attitude greater than 10 degrees, nose down; or

c) bank angle greater than 45 degrees; or

d) within the above parameters, but flying at airspeeds inappropriate for the conditions.

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You can imagine that an upset to Airbus 350 might not be upset to F-16. Then the upset parameters should get defined for pilots in flight operations. In general, for this type of airplane that what is an upset should be defined as.

What are these parameters? Do pilots know that? If we ask 10 pilots the definition of upset, we still get 11 definitions. Do they know how to recognize those parameters and then be able to call out for it.

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Upset Definition ;

"In other words, the airplane is not doing what it was commanded to do and is approaching unsafe parameters."

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Three Main Causes of Upset

An upset, whether caused by

  • External factors (e.g. clear air, mountain wave or wake turbulence, wind shear, etc.),

  • Systems factors (e.g. autopilot malfunction, attitude reference error, etc.)

  • Pilot induced factors (e.g. inattention, fatigue, disorientation, etc.)



WHY THIS IS SUCH A PROBLEM?



In the figure, the upset pitch and bank parameters defined earlier are indicated in green. The aviation industry has historically banked on a pilot – or the aircraft’s autopilot – being able to remain within these parameters. Yet these upset boundaries represent only 5% of the complete aircraft envelope (which is indicated in red), and history – and statistics – show that aircraft repeatedly stay outside of them.

Upset can place an aircraft well outside of defined upset or exposed parameters very quickly – to anywhere within the pitch and bank envelope of the aircraft.

Moreover, normal licensing training exposes a pilot only briefly to parameter limits more than industry defined upset parameters, as indicated in yellow in the above figure. Yet still, this exposed limit represents only 11% of the complete aircraft envelope. ------------------------------

THE SOLUTIONS

Unfortunately, without any demonstrated ability to implement an effective solution commercial aviation will continue to be plagued by high rates of Loss of Control In-flight fatalities until effective UPRT is provided to pilots to mitigate the threat.

Where technology benefits to Control Flight Into Terrain (CFIT) but technology does not benefit to LOC-I and it won't because the more complex airplanes, the more complex they will fail. Pilots always remain the last resort. "We still have to count on the pilot to save the day"

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APS ADDRESSES THE LOSS OF CONTROL IN-FLIGHT (LOC-I) THREAT

Aviation Performance Solutions (APS) is on the leading edge of worldwide industry solutions to loss of control in-flight through industry-compliant Upset Prevention and Recovery Training (UPRT).

One of APS's worldwide training base is located at Khon Kaen airport, Thailand. Operated by Specialized Aviation Training (SAT) or APS ASIA PACIFIC.

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We help pilots bring everyone home safely.


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