Monthly Archives: December 2017


Commercial Multi-Engine Add-On

The Multi-Engine Add-on was a quick and relatively easy add-on, however its important to note that having a second engine is not a panacea for safety. In fact, the second engine is really just one more thing that can kill you. Insurance rates and stipulations alone should be evidence enough that ME airplanes in the hands of general aviators with marginal proficiency and experience is higher risk than single engine airplanes. The attitude that a second engine makes you safer is only true if you are very proficient with your ME aircraft, and you treat engine failures with the due respect they deserve. Fly coordinated, turn away from your bad engine, and watch the video below!

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One additional note: As you learn about Vmc you will frequently encounter the acronym COMBATS. Be aware that most sites and schools are teaching this incorrectly. Many sites list the M, as being MAX GROSS WEIGHT. This is patently false, and should be correctly stated as the MOST UNFAVORABLE WEIGHT, which is typically the minimum take-off weight (30min of fuel), not max gross. When you understand Vmc you’ll understand why the minimum weight results in the worst possible control condition. If you need further proof, you can consult the following references: AFH 12-28, CFR 23.149, AC-8A page 60 Section 48(c)(1), and AC 25-71 change 1. Specifically, AC-8A: Flight Test Guide for Certification of Part 23 Airplanes states “The critical loading for Vmc testing is generally minimum weight and maximum aft c.g…”

Study documents & notes – click here.

The below video is spot on – and should be mandatory viewing for any ME student / applicant.