Name:   twc - Subject:   Question for McGill Date:   10/2/2017 2:10:09 PM

Since UEM is not answering, and, since I have a little experience with this, mind if I answer? 

Short answer, an engine failure in modern aircraft is more an inconvenience than an emergency. Sure, nobody wants to deal with such an inconvenience but they happen from time to time. In a 2 engine commercial airline type aircraft, you have many systems to assist with the loss of thrust in an engine failure. Rudder boost or rudder bias. A system that uses bleed air from the operating engine to assist in opposit rudder to counteract the loss of thrust from the failed engine. In aircraft with hydraulic controls, you might have boosting from the hydraulic system. 

But there are certifications standards that must be met. With airline types and even many private jets are certificated under part 25 of the Federal Aviation Regulations. By standard, they have to accelerate to a take off decision speed (V1) and either abort the take off or, have sufficient runway to accelerate to VR (rotation speed) and continue the take off successfully. Those numbers vary with weight and temperature and field elevation and are calculated for every take off AND a 1.15% adjustment is added to those numbers. Even more,for wet or contaminated conditions. 

For 3 and 4 engine jets, there are additional requirements and some restrictions are removed for obvious reasons. I don't have any 4 engine experience so I can't speak directly to that. But you are correct, loosing the far outboard engine would cause some aerodynamic factors but I do know that the certification standards are the same. 

Hope this answers your questions. 

Peace,

TC