V2 and the 4 segment climb

[WacoFan]

I agree with Jtrain, Surreal, and MikeD all at the same time. I think AA191 may be simply one of those instances where everyone was scheduled to die that way. I remember when that wreck happened and it was hideous. After learning about it, it was even more hideous. Just way to much worst case scenario in that wreck. FO not having a stick shaker, knew they lost an engine, but I'm not sure they immediately knew that had literally "lost the engine". The engine departing ripped up the hydraulics retracting the slats on the left side, the FO was flying and didn't feel the shaker because he didn't have one on the right, slowed to V2 and it rolled on its back. Just a sickening wreck. Mike - do I pretty much have those facts correct?

So, I agree with Surreal and Jtrain about "fly the profiles - odds are you'll be safer" but also understand Mike's points as well as his example about when he'd reject after V1.

I love these conversations.

 

[MikeD]

I agree with Jtrain, Surreal, and MikeD all at the same time. I think AA191 may be simply one of those instances where everyone was scheduled to die that way. I remember when that wreck happened and it was hideous. After learning about it, it was even more hideous. Just way to much worst case scenario in that wreck. FO not having a stick shaker, knew they lost an engine, but I'm not sure they immediately knew that had literally "lost the engine". The engine departing ripped up the hydraulics retracting the slats on the left side, the FO was flying and didn't feel the shaker because he didn't have one on the right, slowed to V2 and it rolled on its back. Just a sickening wreck. Mike - do I pretty much have those facts correct?

So, I agree with Surreal and Jtrain about "fly the profiles - odds are you'll be safer" but also understand Mike's points as well as his example about when he'd reject after V1.

I love these conversations.

Correct. It doesn't appear they were aware of the actual loss of the engine itself from the airframe, and the resultant damage. Individual failures and problems could've likely been easily handled by the crew. It was the failures and problems combined and at a critical flight phase that placed the crew, through their procedurally proper reactions, to be put in a square corner they couldn't get out of.

 

[WacoFan]

Correct. It doesn't appear they were aware of the actual loss of the engine itself from the airframe, and the resultant damage. Individual failures and problems could've likely been easily handled by the crew. It was the failures and problems combined and at a critical flight phase that placed the crew, through their procedurally proper reactions, to be put in a square corner they couldn't get out of.

Are there other accidents that have happened that was made worse by following the procedure?

 

[Polar742]

Most airliners have a 3-segment climb. The J31 had a special certification which included a 4th segment, which was from the lift off to the point the gear was retracted. The reason that was done was because the plane wouldn't necessarily climb on one with the gear out.

Now, that being said, I believe I conveyed some incorrect thoughts in another post.

There are really three scenarios for a continued takeoff: 1) A successful takeoff; 2) An engine failure at V1 - the certification and training scenario; and 3) engine loss after V1

In all instances, OEI performance is considered and we set the aircraft up for a "V1 cut". Trims, the three degrees per second rotation and target takeoff pitch are all predicated on the perfect engine failure scenario, giving that three-degree-per-second rotation into V2.

An All-engines takeoff after you rotate, you will exceed V2. Some operators may want you to pitch to that number. However, once you pass V1 with all engines running you have excess energy at that point. In this scenario, my aircraft will capture a speed up to V2+25. Other aircraft may have different logic, or the speed bug might stay put (Of course, referring to aircraft with flight directors and various vertical modes)

For the third scenario, all engines operating into an engine loss after V1. The aircraft will have far more energy than an engine loss at V1. In this instance, the aircraft should be flown between V2 and v2+10. If you are above V2+10, as far as my knowledge goes, you should convert some of that energy and fly to V2+10.

Finally, in the V1 cut scenario, the aviation gods have aligned and a theoretical event actually happens. At that point, you're going flying. Due to the energy state of the aircraft, a nominal rotation should set you into your target speed right about V2. There shouldn't be excess energy to bleed at that point.

V2 is like Vref. It's a -0/+X speed. You should never be below it.

In any instance, VFR/VMC/IFR/IMC or if you're covered in green slime, you fly that engine out profile. An emergency that you have trained for and are set up for really shouldn't be a time to invent.

This brings around aborts.

Most operators I know of, and indeed the two I have worked for, take a couple abort philosophies. First, is Below 80 knots. You abort for anything. Above 80 knots, you abort for major things that will keep the aircraft from flying. At V1, you fly. More advanced aircraft even have inhibitions built into the EICAS to support this idea.

Bad things typically happen for post-V1 aborts in Part 25 airplanes.

 

[ppragman]

Most airliners have a 3-segment climb. The J31 had a special certification which included a 4th segment, which was from the lift off to the point the gear was retracted. The reason that was done was because the plane wouldn't necessarily climb on one with the gear out.

Now, that being said, I believe I conveyed some incorrect thoughts in another post.

There are really three scenarios for a continued takeoff: 1) A successful takeoff; 2) An engine failure at V1 - the certification and training scenario; and 3) engine loss after V1

In all instances, OEI performance is considered and we set the aircraft up for a "V1 cut". Trims, the three degrees per second rotation and target takeoff pitch are all predicated on the perfect engine failure scenario, giving that three-degree-per-second rotation into V2.

An All-engines takeoff after you rotate, you will exceed V2. Some operators may want you to pitch to that number. However, once you pass V1 with all engines running you have excess energy at that point. In this scenario, my aircraft will capture a speed up to V2+25. Other aircraft may have different logic, or the speed bug might stay put (Of course, referring to aircraft with flight directors and various vertical modes)

For the third scenario, all engines operating into an engine loss after V1. The aircraft will have far more energy than an engine loss at V1. In this instance, the aircraft should be flown between V2 and v2+10. If you are above V2+10, as far as my knowledge goes, you should convert some of that energy and fly to V2+10.

Finally, in the V1 cut scenario, the aviation gods have aligned and a theoretical event actually happens. At that point, you're going flying. Due to the energy state of the aircraft, a nominal rotation should set you into your target speed right about V2. There shouldn't be excess energy to bleed at that point.

V2 is like Vref. It's a -0/+X speed. You should never be below it.

In any instance, VFR/VMC/IFR/IMC or if you're covered in green slime, you fly that engine out profile. An emergency that you have trained for and are set up for really shouldn't be a time to invent.

This brings around aborts.

Most operators I know of, and indeed the two I have worked for, take a couple abort philosophies. First, is Below 80 knots. You abort for anything. Above 80 knots, you abort for major things that will keep the aircraft from flying. At V1, you fly. More advanced aircraft even have inhibitions built into the EICAS to support this idea.

Bad things typically happen for post-V1 aborts in Part 25 airplanes.

That'll buff right out.

 

[Bumblebee]

Please take part more often. Not sure where you're located, but go to a M&G. Get to know these folks here. It's a great community with great people, even if we don't always see eye to eye when reading each other's rhetoric-laced phrases.

.

true, and well done

 

[MikeD]

Bad things typically happen for post-V1 aborts in Part 25 airplanes.

Agree, under all normal circumstances (as "normal" as an engine failure can be ). And as an aside, worse things can happen when taking a severe-problem aircraft with known structure damage or fuselage/cabin fire aircraft airborne just because you're past V1. It's a damned if you do, damned if you don't situation in some cases.......a "do I accept the overrun and keep the burning aircraft on the ground, or do I take it airborne knowing I won't likely make it back?" Its a guts call. I try to keep really bad aircraft on the ground and accept the need to survive doing some 4x4, versus taking a real bad plane airborne. Of course, that assumes you know or realize what the exact problem is and its severity, in the short amount of time post- V1.

And again, it just depends: At KDMA in the C550, we have a 13,500 ft runway, so V1 often equals VR (technically exceeds, even though we can't take that into account), so we could potentially even land on the remaining runway after liftoff and stop.

 

[WacoFan]

If the Concorde guys had known how badly they were hosed an abort even at their speed would have been preferable I think - everyone may have died, but a better chance someone would live I'd think.

 

[Bandit_Driver]

Most airliners have a 3-segment climb. The J31 had a special certification which included a 4th segment, which was from the lift off to the point the gear was retracted. The reason that was done was because the plane wouldn't necessarily climb on one with the gear out.

Now, that being said, I believe I conveyed some incorrect thoughts in another post.

There are really three scenarios for a continued takeoff: 1) A successful takeoff; 2) An engine failure at V1 - the certification and training scenario; and 3) engine loss after V1

In all instances, OEI performance is considered and we set the aircraft up for a "V1 cut". Trims, the three degrees per second rotation and target takeoff pitch are all predicated on the perfect engine failure scenario, giving that three-degree-per-second rotation into V2.

An All-engines takeoff after you rotate, you will exceed V2. Some operators may want you to pitch to that number. However, once you pass V1 with all engines running you have excess energy at that point. In this scenario, my aircraft will capture a speed up to V2+25. Other aircraft may have different logic, or the speed bug might stay put (Of course, referring to aircraft with flight directors and various vertical modes)

For the third scenario, all engines operating into an engine loss after V1. The aircraft will have far more energy than an engine loss at V1. In this instance, the aircraft should be flown between V2 and v2+10. If you are above V2+10, as far as my knowledge goes, you should convert some of that energy and fly to V2+10.

Finally, in the V1 cut scenario, the aviation gods have aligned and a theoretical event actually happens. At that point, you're going flying. Due to the energy state of the aircraft, a nominal rotation should set you into your target speed right about V2. There shouldn't be excess energy to bleed at that point.

V2 is like Vref. It's a -0/+X speed. You should never be below it.

In any instance, VFR/VMC/IFR/IMC or if you're covered in green slime, you fly that engine out profile. An emergency that you have trained for and are set up for really shouldn't be a time to invent.

This brings around aborts.

Most operators I know of, and indeed the two I have worked for, take a couple abort philosophies. First, is Below 80 knots. You abort for anything. Above 80 knots, you abort for major things that will keep the aircraft from flying. At V1, you fly. More advanced aircraft even have inhibitions built into the EICAS to support this idea.

Bad things typically happen for post-V1 aborts in Part 25 airplanes.

Well said Polar... It is normally bad JuJu to abort above v1. Things normally do not turn out good.

MikeD, as you well know aborting has to take into account many variables in the matter of usually a second or less and the PIC may not always know the damage to the aircraft. In general it is usally safer to fly than do a high speed reject.

 

[ppragman]

I think (and this is from my limited experience) that it depends on what you're flying. A beech 1900 on a 10000' runway sealevel standard day and you get a fire light during rotation? Slap the power back and keep it on the ground (ymmv) different story with a CRJ obviously.

 

[MikeD]

Well said Polar... It is normally bad JuJu to abort above v1. Things normally do not turn out good.

MikeD, as you well know aborting has to take into account many variables in the matter of usually a second or less and the PIC may not always know the damage to the aircraft. In general it is usally safer to fly than do a high speed reject.

Precisely, which is why I made that distinction of "...if the crew even realizes". IF the crew is able to realize somehow, then you may just be dead anyway if the problem is bad enough. As I said in my accident synopsis of NASA 712, I personally wouldnt take a dual-gen failure airborne into IMC in my former aircraft, as I'd be guaranteed to be dead, or someone else would be if I took the nylon-letdown route. And there are other things I would have in the back of my mind to abort for high speed, as going airborne with those would be guaranteed death for myself or someone else on the ground, vice possible death for me at the overrun.

It all depends on the variables and factors you talk about. Generally speaking though, for "simple" things like an engine failure, anti-skid fail, high-speed tire blowout, etc, getting airborne is generally safer than the high speed abort, I fully agree.

The procedures HAVE to be known and followed, I'm not arguing against that. Am just saying that for the times when something outside the book answer may be encountered, one needs to understand that prudence and good judgement might need to supercede a procedure that while normal, may make the situation worse. That kind of judgement will come with experience; and will depend on a good number of factors.

 

[Bandit_Driver]

If the Concorde guys had known how badly they were hosed an abort even at their speed would have been preferable I think - everyone may have died, but a better chance someone would live I'd think.

I wouldn't be so sure. I was given the blown tire scenario in the 727 at a high speed and it was still better to fly it. Re-ran it with the abort and you just can't stop on blow tires, went off the end and it wasn't pretty. Seen the same scenario in an E170, same results. Had the Concord crew aborted they probably would have been off the end through the fence and a fireball just the same. The pilot almost pulled it out. Unfortunately, the multiple failures did them in. Had then been able to get the gear up they probably would have made it around. Remember the fireball started because of the sparking wires on the landing gear that were severed. They get the gear up they live. The don't have the fireball eating away at control surfaces they may have made it as well.

When you get into multiple system failures all at once you better hope God and lady luck are on your side that day and it isn't your time.

 

[MikeD]

I wouldn't be so sure. I was given the blown tire scenario in the 727 at a high speed and it was still better to fly it. Re-ran it with the abort and you just can't stop on blow tires, went off the end and it wasn't pretty. Seen the same scenario in an E170, same results. Had the Concord crew aborted they probably would have been off the end through the fence and a fireball just the same. The pilot almost pulled it out. Unfortunately, the multiple failures did them in. Had then been able to get the gear up they probably would have made it around. Remember the fireball started because of the sparking wires on the landing gear that were severed. They get the gear up they live. The don't have the fireball eating away at control surfaces they may have made it as well.

When you get into multiple system failures all at once you better hope God and lady luck are on your side that day and it isn't your time.

The NASA 712 link is exactly this scenario, high speed abort versus fly, with a blown tire on takeoff. Good discussion on it too.

The Concorde crew was guaranteed death with liftoff, but not due to just the blown tire; but because of the damage the blown tire did just at liftoff. And whether the crew way up front realized the fire they had going or not, they were already committed to going airborne. It was the worse damned if you do, damned if you don't situation.

 

[Bandit_Driver]

Mike, do you have a link to the NASA writeup on the scenario?

 

[MikeD]

Mike, do you have a link to the NASA writeup on the scenario?

Here's my MikeD Accident Synopsis on it:

I do a detailed RTO analysis discussion as well as bring the Concorde accident into the discussion.

http://forums.jetcareers.com/technical-talk/91792-when-mr-murphy-rides-your-jumpseat.html

 

[WacoFan]

Concorde, AA191, UAL232 - sometimes you're just given a crappy hand. Sh_ _ Happens I think.

 

[WacoFan]

Here's my MikeD Accident Synopsis on it:

I do a detailed RTO analysis discussion as well as bring the Concorde accident into the discussion.

http://forums.jetcareers.com/technical-talk/91792-when-mr-murphy-rides-your-jumpseat.html

Man - That's a great write up. You should take over writing Aftermath in FLYING after Peter Garrison gets done.

 

[MikeD]

Man - That's a great write up. You should take over writing Aftermath in FLYING after Peter Garrison gets done.

Thanks for the words. There's 13 of these buried here within the Tech Topics section, with more coming soon.....in fact in one day.

 

[Bandit_Driver]

Here's my MikeD Accident Synopsis on it:

I do a detailed RTO analysis discussion as well as bring the Concorde accident into the discussion.

http://forums.jetcareers.com/technical-talk/91792-when-mr-murphy-rides-your-jumpseat.html

MikeD, great writeup on 712. It was very interesting and it has even given me a few more things to think about in the abort arena. I wish I had your way with the prose.

Also didn't mean to offend you, if I did in my earlier post, I appoligize.

 

[MikeD]

MikeD, great writeup on 712. It was very interesting and it has even given me a few more things to think about in the abort arena. I wish I had your way with the prose.

Also didn't mean to offend you, if I did in my earlier post, I appoligize.

No, no offense taken at all. It's a great discussion all around, and brings good things for all of us to consider. Talk about one subject where there's no one answer that covers all. As I stated in the writeup, "V1 is one of those black and white phenomenas that upon closer inspection, can contain many shades of grey insofar as being a hard and fast number for continuing or rejecting a takeoff based on differing emergencies." And I truly believe that.

Whats interesting about the 712 accident is how the event was filmed from onboard purely by chance. Its a very interesting video to watch, as the tire slowly begins deforming and coming apart.

Another interesting RTO is TWA 843, L-1011, 30 July 1992 KJFK.