Which is worse?

[multi_engined]

I was just curious to know from a proffessional pilots point of view which is worse? Also do the airlines place equal training into both situations?

-Engine Failure After Takeoff
-Engine Failure On Approach (Say 300ft)

[Oshkosh George]

I'm not a pilot,but I would say take-off without a doubt. This event may not leave enough power to keep the aircraft in the air,especially if fully loaded,which could well be true fuel-wise at least if departing for a longish flight.

If landing,then the other engines would almost certainly provide enough power to complete the manoeuvre,as they are in a low setting anyway. If single engined,it may be able to glide the distance remaining from 300 ft.

[Jet2]

Takeoff. The engines are operating at a much higher thrust and therefore, on aircraft with wing mounted engines like the 737, there is a significant swing (yaw) encountered which must be controlled with rudder input.

On approach the engines are providing less thrust so any failure of one won't induce as much yaw. Also, an aircraft finds it an awful lot easier to descend on one engine than climb :D

Both are manageable though and we frequently get them on simulator checks.

Hope this helps ;)

[barit1]

On approach, engines are at such low power it's very unlikely they'll quit -- if they have fuel.

If all the engines quit, the plane will land itself.

Guaranteed. :)

[misd-agin]

[quote=Oshkosh George]I'm not a pilot,but I would say take-off without a doubt. This event may not leave enough power to keep the aircraft in the air,especially if fully loaded,which could well be true fuel-wise at least if departing for a longish flight.


The planes are designed to be able to climb out at max takeoff weight with an engine failure.

Leave the technical/professional questions to the professionals.

[mutt]

The planes are designed to be able to climb out at max takeoff weight with an engine failure.

Yep they can, but not 100% of the time...

Mutt

[chornedsnorkack]

On approach, engines are at such low power it's very unlikely they'll quit -- if they have fuel.
If all the engines quit, the plane will land itself.
Guaranteed. :)

This in no way rules out ingesting a flock of fat geese into the engines (multiple birdstrike risk on landing should be the same as on takeoff, or higher if the plane does not make as much noise and the birds do not hear it and realize they should duck). Are engines resistant to birds when running at low power?

Also, if an engine quits on runway, the plane has a precisely known initial height and alignment. If the engine quits on climb, there is a wide takeoff chimney ahead. Whereas a landing plane must wind up reaching a precisely known direction, line, region of runway and groundspeed. So, an engine failure on approach might lead to a missed approach... With all engines quitting, the plane can miss landing in any direction (touch down before runway, touch down late and overrun, run off the side of runway, touch down beside the runway...). It was recently reminded that even planes with all engines functional are not certified to reject takeoff in the low-energy landing configuration (flaps and landing gear out) but are committed to land. Whereas planes taking off are supposed to accelerate with one engine out, gear down, high-lift deployed...

So, can planes go around with one engine out?

[Intruder]

Except for airplanes that are refueled in the air, landing weight is always less than takeoff weight. For most jets that difference is large. Therefore, thrust required for the same performance (speed, climb rate, etc) is significantly less.

Transport airplanes are designed with enough thrust to continue to accelerate and takeoff before the end of the runway if one engine fails after a defined point (V1). Therefore, a go-around with a failed engine is even less problematic.

In the simulator, an engine failure at low altitude on the approach is a "non-event" in the 747. If it is an inboard engine and the autothrottles are engaged, the Pilots may not even notice until the generator lights come on...

[mutt]

It was recently reminded that even planes with all engines functional are not certified to reject takeoff in the low-energy landing configuration (flaps and landing gear out) but are committed to land.

Would you be so kind as to supply a reference for that little piece of mis-information.

So, can planes go around with one engine out?

FAR25 aircraft certainly can!

Thanks

Mutt

[misd-agin]

Yep they can, but not 100% of the time...

Mutt

For a simple engine failure they're designed, and certified, to be able to do it 100% of the time.

Add other issues and the odds obviously get worse.

[chornedsnorkack]

Would you be so kind as to supply a reference for that little piece of mis-information.
FAR25 aircraft certainly can!
Thanks
Mutt
This:
http://www.tc.gc.ca/civilaviation/commerce/circulars/AC0141.htm

Maybe misinterpreted... but it seems that an aircraft in a low-energy landing regime is worse off than an aircraft on takeoff.

[Oshkosh George]

[quote=Oshkosh George]I'm not a pilot,but I would say take-off without a doubt. This event may not leave enough power to keep the aircraft in the air,especially if fully loaded,which could well be true fuel-wise at least if departing for a longish flight.


The planes are designed to be able to climb out at max takeoff weight with an engine failure.

Leave the technical/professional questions to the professionals.

He never said how many engines his theoretical aircraft had,or indeed,how many of them failed. It possibly only had one engine in the first place. Call yourself a professional?:mad:

[Intruder]

it seems that an aircraft in a low-energy landing regime is worse off than an aircraft on takeoff.
Not at all!

All it says is that if the decision to go around is made at less than 50' -- AFTER a decision to land has been made -- the airplane may actually touch the ground in the process of the go-around. There is nothing "dangerous" about this; it is simply a "touch and go" in the midst of the go-around, and becomes by some definitions a "balked landing." After the touchdown, the subsequent climbout is generally no problem whatsoever.

[chornedsnorkack]

Not at all!
All it says is that if the decision to go around is made at less than 50' -- AFTER a decision to land has been made -- the airplane may actually touch the ground in the process of the go-around. There is nothing "dangerous" about this;
It also says:

An attempt to commence a go-around or balked landing while in the low-energy landing regime is a high-risk, undemonstrated maneuver.


it is simply a "touch and go" in the midst of the go-around, and becomes by some definitions a "balked landing." After the touchdown, the subsequent climbout is generally no problem whatsoever.
It is warned that this:

may result in a stall

[one dot right]

You never mentioned if the engine that fails is a propeller or a jet

In a turboprop on approach you will have no autofeather protection due to the engines being at low power. You are now left with a high drag/windmilling propeller which,if you wish to go around, will have to be identified and secured before going around:eek:

[mutt]

chornedsnorkack

You really have to put it in context, they are talking about an aircraft that is flared to land, this isnt the same as the certification requirements for approach climb and landing climb.


In brief, an aircraft is not certified to successfully complete a go-around without ground contact once it has entered the low-energy landing regime. For the purposes of this CBAAC, the low-energy landing regime is defined as:

aircraft flaps and landing gear are in the landing configuration;
aircraft is in descent;
thrust has stabilized in the idle range;
airspeed is decreasing; and
aircraft height is 50 feet* or less above the runway elevation.

For a simple engine failure they're designed, and certified, to be able to do it 100% of the time. So why do we get lower weights when the temperature gets hotter?

Mutt

[Intruder]

An attempt to commence a go-around or balked landing while in the low-energy landing regime is a high-risk, undemonstrated maneuver.
Dunno what that writer's experience is, but it sounds more like a lawyer's "CYA" statement than a professional Pilot's.

We demonstrate it as part of our Cat II/III training in the simulator. Our Flight handbook allows for go-around / balked landing up to the time the reverser levers are pulled.

Again, "ground contact" is not evidence of a failed go-around or dangerous situation. It is merely the inevitable result of a late-initiated go-around.

[misd-agin]

So why do we get lower weights when the temperature gets hotter?

Mutt[/quote]

Because there's not enough engine power at the higher temperature to ensure engine out runway or climb performance.

To ensure acceptable performance is achieved the a/c's weight must be reduced.

[misd-agin]

[quote=misd-agin]

He never said how many engines his theoretical aircraft had,or indeed,how many of them failed. It possibly only had one engine in the first place. Call yourself a professional?:mad:

Ok, we can be silly. He said "engine failure" on T.O. or landing. I thought engine failure means one, and engine failures means more than one. I guess English isn't the same everywhere.

We can be silly and come up with 1000 thousand "what if's?" Takeoff on 31L at JFK? SEL? You'll always have runway ahead of you until you're so high that you can do a 180 degree turn and glide to a landing on 13R.

Same thing with landing on 13R. SEL with engine failure at 300'? So what, just land on the displaced portion of the runway.

Takeoff at extremely light weight at JFK vs. landing at max allowable in a snowstorm with CAT III mins? Well of course I'd rather have the good weather T.O. scenario. "What if....."

The basic question remains - what's worse, lose an engine on T.O. or landing? T.O. Period.

We spend huge amounts of training time on engine failures on T.O. Almost zero on engine failures during the landing phase. Why? Because landing failures are relatively benign events. 408,000# for takeoff, 310,000# for landing. Same engine power. Where'd you rather lose the engine?

Instructors if anything like to sneak approach engine failures into the sim ride. It's to see how long it takes for the pilots to discover the failure and how they deal with it.

Often times descent and configuring is done at idle power(multi-engine glider until you spool up the engines). Losing an engine is easy to miss because there's almost no change until systems(hydraulics, electrical loads, etc) start changing to deal the engine failure.

You can't sneak an engine failure by someone on T.O.

It's not uncommon in the sim to do s/e go-arounds. If commanded late in the approach the a/c will land but you just do a s/e touch and go. It's no big deal.

Airliners are certified to be able to make all runway and climb restrictions for the weight, and temperature, they're operating at. And the most restrictive portion of the departure is the weight that we can't operate above. 100% of the time. Period.

[Oshkosh George]

"The basic question remains - what's worse, lose an engine on T.O. or landing? T.O. Period."

Which is,I believe ,what I said! I didn't really like your condescending tone though. I'd still like to point out that a single engine aircraft is NOT designed to continue climbing after an engine failure,and you were assuming it wasn't single engined. Blinkered,I'd say.

I see you have vast experience,but that doesn't give you a right to be rude.:=

End of rant.

[misd-agin]

"The basic question remains - what's worse, lose an engine on T.O. or landing? T.O. Period."

Which is,I believe ,what I said! I didn't really like your condescending tone though. I'd still like to point out that a single engine aircraft is NOT designed to continue climbing after an engine failure,and you were assuming it wasn't single engined. Blinkered,I'd say.

I see you have vast experience,but that doesn't give you a right to be rude.:=

End of rant.

As we stay in the States "two points" (similar to 'bullseye', or you're correct and made your point).

He's a PPL student. I made the assumption that by 'professional pilots' he would be interested in multi-engined a/c(goes by 'multi-engine'...).

And I see your point that my reply was rude. My apologies.

"Blinkered?"

[Oshkosh George]

misd-agin

Thanks for your nice reply. I'll make this the last on our banter,before being accused of taking over the thread!

Don't your racehorses have blinkers in the States? They are shields on the side of the horses eyes,so that the horse only sees ahead,presumably to avoid distractions from peripheral vision/spectator movement. Therefore "blinkered" means (in your case) answering without thinking about all the possibilities.