Vx vs. Vy

[Checks]

"3. If the engine fails immediately put in full flaps, pitch down for your best glide speed with flaps and bank 30-45 deg. Be carefull to have enough airspeed as to not stall."

KSU,

Could you explain your reasoning for this? I personally wouldnt put in full flaps unless I had the landing point made. Full flaps is going to just add a lot of drag.

 

[ksu_aviator]

With full flaps you slow down the aircraft and shorten your turning radius so that it is easier to make the tight turn to the runway.

 

[Flightjock30]

This Vx vs. Vy debate is a coincidence because I received the July 2002 issue for AOPA Pilot magazine and Barry Schiff wrote an article about the decision of turning back to a runway after an engine failure in a single. He is qouted as saying "Although initial climb at the best-angle-of-climb airspeed (Vx) results in more altitude over the departure end of the runway than when using the best-rate-of-climb airspeed (Vy), pilots should recognize that an engine failure and delayed action at Vx result in a more rapid speed bleed that places the aircraft in greater danger of stalling. Furthermore, the transition from such a nose-high attitude to a gliding attitude requires lowering the nose aggressively, an action that to initially fill the windshield with rapidly rising terrain. This can startle even those prepared for such a low altitude phenomenon. Although a climb at Vy can reduce the likelihood of a return to the runway, the additional airspeed it provides might be more desirable."

As for my two cents. Even if you have enough altitude to turn around and make it back to the runway have you considered another aircraft that is just lifting off behind you? As you roll out of a turn facing the departure runway downwind you may be face to face with another plane that just lifted off. He won't be able to see you at a climbing pitch attitude most likely. At a busy airport this could happen and you may not have time to inform ATC of your failure! So of course the use of good aeronautical decision making is very important in a return back to the airport after a power loss.

 

[172driver]

A CFI at our school just got put on probation for making a low altitude return to the airport. He was @ 400'AGL, partial power loss to 1200 RPM, C172, nothing but trees ahead. He made the runway, actually overshot by 5 ft into the grass before stopping, nothing damaged.

We always brief landing straight ahead below 1000' thus the disciplinary action. The point is...those in authority frown upon low altitude returns in any scenario. If something is broken or injured, you are in big trouble.

He did a good job getting back. Who knows what would've happened had he elected to land in the trees. However, it could've been one of those all too common stall, spin, crash, die accidents. My two cents...perform it as you brief it.

 

[dmspilot00]

Sometimes climbing at Vx can be good insofar as getting through an initial cloud layer, low lying band of weather (beware icing)etc after takeoff, at least this is what I was taught once upon a time.

I don't see how that is possible, when it will take you a lot longer to climb above a cloud layer (or to any altitude) at Vx. Vy is the speed that gives you the fastest rate of climb.

 

[172driver]

Yes, but if you are VFR trying to get through a hole, sometimes Vx is necessary. It's just like clearing the trees on takeoff. I think that was the intention of the previous post.

 

[ksu_aviator]

How many FO's have second jobs that may even pay more than what they earn here a Mesaba

Well, obviously he made the correct choice. But I hope he had practiced that maneuver first. I don't think that your higher ups are right for putting a pilot on probation for making a good decision.

With nothing but trees in front of him, I don't see a good scenario ahead.

My rule...do it as you brief it but don't follow the rules to your death. Thats like not firewalling an engine in windshear...who cares if the engine is still good after you crash? Same applies here. The brief wasn't a good brief. You have to be able to seperate what is right versus what is written. Make good decisions and have good situational awareness. You can't brief every possible scenario either.