jetcareers - View Single Post - Vmc: Flap and Gear Positions, 5 degrees of bank and Max Gross

pscraig · September 17th, 2003, 13:16

We teach that deploying flaps increases stability, and decreases Vmc. Your description of keel effect is fine, and it does decrease Vmc. You are correct that use of max gross weight and up to 5 deg bank into the operating engine will lower Vmc. You are creating a horizontal component of lift by doing this, which reducees the amount of rudder pressure required to maintain directional control. The magnitude of this horizontal component is proportional to the weight of the aircraft since the heavier the aircraft, the greater the amount of total lift generated.

The remaining factors you listed do increase Vmc. I disagree with the examiner, and at that point would start pulling out the AFH (chapter 14) and stack of ACs.

The DPE didn't "buy" the zero sideslip concept??? That baffles me.

I do see some problems in comparing your answer list to the questions however, looks like they might have been typed incorrectly? (#4 should be AT, etc)

September 17th, 2003, 13:16	#4
pscraig Senior Member Join Date: Jul 2001 Location: Houston, TX Posts: 1,021	Re: Vmc: Flap and Gear Positions, 5 degrees of bank and Max Gross We teach that deploying flaps increases stability, and decreases Vmc. Your description of keel effect is fine, and it does decrease Vmc. You are correct that use of max gross weight and up to 5 deg bank into the operating engine will lower Vmc. You are creating a horizontal component of lift by doing this, which reducees the amount of rudder pressure required to maintain directional control. The magnitude of this horizontal component is proportional to the weight of the aircraft since the heavier the aircraft, the greater the amount of total lift generated. The remaining factors you listed do increase Vmc. I disagree with the examiner, and at that point would start pulling out the AFH (chapter 14) and stack of ACs. The DPE didn't "buy" the zero sideslip concept??? That baffles me. I do see some problems in comparing your answer list to the questions however, looks like they might have been typed incorrectly? (#4 should be AT, etc)