Dr. Sunjoo Advani

Trim Awareness – A Neglected Child?

Dr. Sunjoo Advani, President, International Development of Technology (IDT)

Dr. Sunjoo Advani is an aerospace engineer with 35 years experience in flight simulation development and operates the company International Development of Technology. Previously, an assistant professor in the Aerospace Department at the Delft University of Technology, his research focused on pilot-vehicle interactions and manual flying. In 2009, he founded the International Committee for Aviation Training in Extended Envelopes, which defined the requirements for Upset Prevention and Recovery Training. These are embodied in ICAO Manual 10011, and recent regulations, including EASA. Currently, he supports several airlines in developing their UPRT programs and applying UPRT to their pilots and instructors. 


Trim Awareness – A Neglected Child?

Today’s airline training programs cover the elements required by regulation, OEM recommendations, and by an operator’s own required training profiles. From several aircraft incidents, including recent events, the awareness of aircraft trim is an issue that apparently must be better understood by pilots. These events have impacted aircraft from several manufacturers, including on FBW and envelope-protected aircraft. 

In modern jets, the effect of trim offsets is often several times more powerful than the effect of the elevator alone. The tailplane, which is adjusted for trim, generates a far greater lifting force than the elevator for the same deflection. The proper use of trim throughout the flight envelope is therefore critical, and fighting against trim offsets must be avoided.

The challenge is how to train pilots to a) recognise and understand trim and b) to apply that knowledge in a timely manner in the unlikely event of a trim failure. This requires both the academics as well as the practical skill-based training. One of the challenges is dealing with the extreme loads and motion cues that can be associated with out-of-trim situations. Creating appropriate and validated training programs for these will be discussed during the presentation.