twin engine climb on one engine

[310]

How many of you knew this? I learned from an article on the AOPA website that if a piston twin has a MGTOW of under 6000lbs and a stall speed under 61 knots that there is no requirement for the plane to climb SE at 5000 msl, but if either the MGTOW is over 6000 lbs or Vso is over 61 knots the required climb ability if determined in the following way.
If Vso is over 61 knots, square the stall speed and multiply by .027 and this gives you required climb performance at 5000 msl. (Example: Vso is 65 knot, 65 squared is 4225. 4225 times .027 is 114. This plane would be required to climb 114 fpm at 5000 msl. I assume this is at gross weight.
Does anybody know where this is in FAR's?
Anyone hear of this during your multi training?

 

[flydog]

Dude if you know that from memory then maybe all of us here need to chip in and get you some cable for your crashpad

 

[banned username 2]

Dude if you know that from memory then maybe all of us here need to chip in and get you some cable for your crashpad

HAHAHAHA!!! I was thinking the same thing!

 

[bigD]

Heated nipples...

That could be a nice feature, especially considering the ice princess I'm dating!

Heh heh - I'm just kidding honey. Seriously, I'm kidding...I'M KIDDING!

 

[Timebuilder]

310, I too was surprised back when I learned that some twins didn't have to posess a positive climb rate on one engine. As mentioned above, it's spelled out in part 23.

Since a few multi students and instructors may stop by this thread, I'll get up on my soapbox and tout two circulars that I included in my instructional package to my multi students:

FAA-P8740-19 Flying Light Twins Safely and

FAA-P8740-25 Always Leave Yourself an Out

Knowing what to expect out of your airplane when it is not at it's best can save your life.

 

[WrightAvia]

Twin sold for a dollar, kills 12...

"According to FAA records, on June 30, 1976, the airplane was sold for salvage...for $1.00"

This crash of a queen air, which killed a bunch of skydivers, a pilot and a guy sitting on his porch watching his kids play, has always captured my imagination. It happened on a sunny day, no ICE, no schedule pushing or thunderstorms. Just enough combinations of bad judgement to really shorten that decision chain.

Here is a link to an interesting and of course tragic crash of a larger piston twin... one that obviously couldn't climb, much less maintain directional control, even at the hands of an ATP.

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001207X04585&key=1

 

[mackinhoes]

There was a pilot from Dallas (ADS) who killed his wife and three kids in a Seneca last thanksgiving. He lost an engine in cruise flight and tried to land in Ada, Oklahoma. His approach was high and he apparently tried to do a single engine go-around.

He was a successful entrepeneur who put his kids through some expensive private schools in Dallas, lived in a nice part of town and was very highly regarded as an asset to the community.

Stall/spin=tragedy.

It's a shame that guys like that don't understand the limitations of their own piloting skills and the danger of twin engine airplanes. "A man's got to know his limitations." Low time pilots or those that don't train regularly with a good MEI with substantial light piston twin time need to fly SE airplanes.

Flying light twins safely is an excellent circular, although a little obtuse. I think I read it 8-10 times before I really understood the big picture.

 

[Timebuilder]

While the 10,000 foot runway at Denver may have been appropriate in terms of accellerate-stop distance, one has to wonder how that 310 managed to get to Denver in the first place, in terms of the possibility of losing an engine on the way.

Since I have no 310 time, I am unfamiliar with the 310's single engine service ceiling. I have a sneaking suspicion that it is close to violating the terrain and obstruction clearance requirements, and better yet, the MEA's for the area.Some of you guys that fly 310's and know about Denver can correct me if I'm wrong.

For instance, the Seneca 1 has a single engine service ceiling of 3650 feet, so an engine failure around Denver would mean a controlled descent into terrain. I'm sure the 310, or other twins such as the Navajo, have better performance on one motor (where the heck is that Navajo POH?) but I am uncertain of the numbers.

Can a 310 lose a motor and still be flown near Denver with a margin of safety?

 

[bigD]

I guess you have to define "margin of safety". I'm not sure that I'd call flying a twin in a region of elevation higher than its single engine service ceiling necessarily dangerous.

Obviously you have to be aware of the limitations, and realize that you're going to have to put it down somewhere soon if you lose an engine, but it's no different than flying a single anywhere.

 

[Timebuilder]

Actually, I think it is very different.

The effect may be similar if both engines quit on a twin, such as in the case of a fuel contamination problem.

If you start with two engines, on the other hand, your chance of having one running when you land is excellent, but you have to decide if you are willing to take on the aditional risk of CFIT if you fly above the single service ceiling while the terrain keeps rising as you fly. If you do, you have deliberatly placed yourself in the same position as the single engine pilot: hoping to find a place to safely land. In mountainous terrain, this has to be more difficult.

It is a decision not to be taken lightly.

 

[bigD]

True, by flying in those situations you are deliberately putting yourself in the same position as a single engine pilot, and you're right - it's not a decision to be taken lightly.

But like anything else, it's a balance between margin of safety and utility of the airplane. Choosing not to operate in the area above the single engine service ceiling would essentially render the twin I fly a VFR only airplane.

 

[Timebuilder]

That's true. One way of reducing risk is to know what terrain is beneath you, or a least having an idea about the terrain, and considering the cloud ceiling above that terrain.

In a single, I like to have a 2,000 to 3,000 AGL ceiling below me in case of an engine loss. That way, I can have some extra time to direct my airplane to a survivable landing from a flight in IMC. Picking a spot to dead stick with a 300 foot overcast might be problematic, at best.

In a twin, I hesitate to fly above single ceiling if the terrain below me is rocky hillsides, powerlines and strong trees. That's my concern about taking a light twin into Denver. I'm sure it gets done every day. Pilots routinely take on added risk. How well pilots manage that risk is sometimes the stuff that investigations are made of.

 

[310]

SE service ceiling on my 310 is 7700 ft msl -at MGTOW of 4830 LBS. Not sure what is would do at say 4200 lbs.

 

[surplus1]

If this thread had been written 30 years ago, it is likely that the content would have been little different.

Light twins (certified under Part 23) are essentially the equivalent of single engine aircraft (climb performance wise) with the power split in half and installed on the wing. They are in fact more dangerous than their single engine equivalent.

I think this is because the training is generally inadequate. This in part because a high percentage, if not morst, MEI's do not themselves understand the performance capabilities of these aircraft and what I call "quickie" multi-engine ratings. Much time is spent on rehearsing engine out procedures and flying around the pattern to successful engine out landings in a very lightly loaded airplane that can't climb away from an engine failure, at a critical point in the real world.

Instructors don't emphasize that the best thing you can do if unlucky enough to have an engine failure in a light twin on take off, is to close the throttle on the good engine and find the best place you can to set it down. Instead, students are conditioned to go through a sequence of shutting down the bad engine and attempting to climb away from the problem -- something that the aircraft is incapable of doing in a majority of situations. In the real world, attempts to duplicate this training exercise usually result in severe airspeed loss, a VMC loss of control problem and the proverbial inverted arrival.

Some day multi-engine training in light twins may become more realistic and tragic accidents reduced. Here's hoping, but not expecting.

 

[Timebuilder]

I agree.

I have emphasized to my students the importance of avoiding a Vmc roll, and that this will often dictate the lowering of the nose to maintain suficient airspeed as you pick a place to set it down. Pushing the nose down is against everything your mind is shouting at you to do, but sometimes you must, and often with pulling the throttle as mentioned above.

I have them work out some performance scenariors based on density altitiude, showing runway length and climb rate. It opens their eyes.

 

[cjh]

Instructors don't emphasize that the best thing you can do if unlucky enough to have an engine failure in a light twin on take off, is to close the throttle on the good engine and find the best place you can to set it down. Instead, students are conditioned to go through a sequence of shutting down the bad engine and attempting to climb away from the problem -- something that the aircraft is incapable of doing in a majority of situations. In the real world, attempts to duplicate this training exercise usually result in severe airspeed loss, a VMC loss of control problem and the proverbial inverted arrival.

This is so true. It seems like the training for engine out is often the same whether discussing engine loss at 100' or 10,000'. I've also heard of using runway distance and/or altitude as the measureing stick for go/no go decisions. However, I like and use a method I learned from a Deakin article at AvWeb. I use blue line as my gear up speed. That does a couple of things: (1) makes my decision to go or land on engine loss easy - gear down I'm landing, gear up I'm flying and (2) reduces the engine out check list to identify, verify, feather.

BTW, on the subject of SE service ceilings, for my Navajo which is a 1969 310hp, it's supposedly 15,800.

 

[jetdriven]

dont forget the crash survivability in a single-engine airplane is usually much better than a twin because
(1) there is big heavy engine out front to absorb impact
(2) touchdown speed is usually 40-60 KIAS instead of a twin's 85-100+KIAS
(3) a twin has a greater than twice the chance of engine failure .
Think how reliable a Lycoming O-320 in a skyhawk is with its simplicity compared to a turbocharged fuel injected TIO-541 in a Navajo.

forget what the book says we shutdown an engine over Hays KS one VMC day (hays is 2000' MSL) and we had to restart it because we could not hold altitude at 3500' MSL on a 70 degree day at 40" (TOGA power). This in a 1978 PA-31-350 with full fuel and two pilots. Gross weight was 7368 and we were about 5500#.

Back to he original story I dont think you'd be able to successfully continue flight in any naturally aspirated twin at Denver regardless of temperature. Exception being perhaps a C-55 or Be-58 285HP baron at 1500# under gross weight and a colder than standard day. even then it would be tough. A lot of turbocharged twins couldnt do it either.

 

[310]

come on; Someone out there has made it home with one feathered. Lets here from you.

 

[mackinhoes]

I've got a lot of time instructing in a Duchess. Here in Dallas it will climb on one engine, even on a hot day, to about 5,000. Losing an engine after takeoff is something you can fly out of, with some qualifications. One, I would not try it (in a real emergency) unless I was out of runway and at a safe altitude - at least 100' agl with no obstructions to climb after runway. (I agree with surplus1 about pulling throttle on good engine and landing on runway - even if it means going off the end. My students heard that many times everytime we flew and on every takeoff briefing on every takeoff.)

The hardest thing students had to learn when I simulated an engine failure after takeoff (this was the last thing I would teach a student, once I was certain they would NEVER make the error of pulling the throttle on the wrong engine, or push the wrong rudder) was to lower the nose for airspeed. In the duchess, it was almost ten degrees pitch attitude change. As long as the student lowered the nose, used proper rudder technique, the engine out maneuver is not too difficult. One of the examiners in Dallas (who most MEI's in Dallas thought was too difficult - but I preferred to send my students to) insisted, rightly, that the student show mastery over this. The other, easy examiner, would never perform this on a checkride. It's been awhile since I looked, but I believe it is a requirement on the PTS. I would never sign anyone off unless they were absolutely 100% perfect on this (and engine out landings, for that matter.) I had to tell one wealthy dentist that I would not fly with him or sign him off when he never could get the hang of it. He wanted to go from a Mooney to a 340. I told him to buy a 210.

 

[310]

Performance Loss of Representative Twins with One Engine Out

Pistons

All engine

climb (fpm)
S.E. climb

(fpm)
Percent

loss

Beech Baron 58
1,694
382
80.70

Beech Duke
1,601
307
80.82

Beech Queen Air
1,275
210
83.53

Cessna 310
1,495
327
78.13

Cessna 340
1,500
250
83.33

Cessna 402B
1,610
225
86.02

Cessna 421B
1,850
305
83.51

Piper Aztec
1,490
240
83.89

Piper Navajo Chieftain
1,390
230
83.45

Piper Pressurized Navajo
1,740
240
86.21

Piper Seneca
1,860
190
89.78

Turboprops

All engine

climb (fpm)
S.E. climb

(fpm)
Percent

loss

Beech King Air 90
1,870
470
74.87

Mitsubishi MU2-J
2,690
845
68.59

Rockwell Commander 690A
2,849
893
68.66

Swearingen Merlin III
2,530
620
75.49

Business Jets

All engine

climb (fpm)
S.E. climb

(fpm)
Percent

loss

Cessna Citation
3,100
800
74.19

Falcon F
3,300
800
75.76

Falcon 10
6,000
1,500
75.00

Gates Learjet 24D
6,800
2,100
69.12

Grumman Gulfstream II
4,350
1,525
64.94

Hawker Siddeley HS 125-600
3,550
663
81.32

IAI 1123 Westwind
4,040
1,100
72.77

Rockwell Sabre 75A
4,300
1,100
74.42

Philiplane, your info on the 310 is wrong. As you can see from the above chart a 310 has a loss of 78% of its climb when on one engine as compared to 81% for a BE58. Poor pilot techinque in letting a 310 side slip by not putting in the correct amount of bank towards the operating engine will degrade performance greatly but done properly they perform well on one engine.
Flap design has nothing to do with this because the flaps should be retracted if SE except on short final.
High wing loading is a plus- gives a better ride and less induced drag.
Clean stall is 73 knots, dirty stall 64 knots and of course Vmc varies with weight and balance but is 76 knots typical. Vyse is 96 knots and Vxse is 83 knots. (both at grosss)
I have read that engineering at Cessna canted the tip tanks and swept the tail on a 310 and was not going to produce the change( because of no benefit) until marketing saw it and said it would sell better with the changes.
I also read of a case where internal wing tanks were added and the tips tanks removed and speed was unchanged. Parasitic drag of course decreased but induced drag increased. The tip tanks keep the air from rolling around the end of the wing, from bottom to top, much in the same way a winglet does the same thing. Besides I like having the fuel as far from the passengers as possible.
Maybe the 310 you flew was "sick".
I do agreed that it is important to maintain proper airspeed at all times while SE in a 310. Recovery (acceleration) takes alot of altitude and you must be clean.
In the nest post I will give the location of the entire article from the AOPA website from which the chart above came from.

 

[310]

http://www.aopa.org/members/files/topics/leaveout.html

This is the location of the article with the info from above.
I think you have to be a AOPA member to access.
The 310 I fly is a C model and is the lightest one built with 260hp per side so maybe it performs better that other 310 models.
Book SE roc is 430 fpm.
I have had instructors pull one several time just after rotation and have always climbed out on one without having to put the pulled back one back into the game.
But be very careful on approach- with gear down and flaps 20 it will not hold altitude with full power on one; so don;t get too dirty too far out and low. It has nine feet of slip flaps per side.
Big Barn Doors.

 

[310]

yes, I think we are talking different models- in what model/year 310 did you experience this?

 

[Timebuilder]

Jetdriven, that's the "real world" answer I expected for the Navajo.

I have a friend who lost a motor in a Navajo near Limerick, Pa, and flew it fully loaded to land at PHL because of the fire apparatus that was available there. He was at about 2,000 the whole way, if I recall correctly.

 

[surplus1]

In general, the problems associated with the marginal performance of light twins operating on one engine are perhaps more complex than those of transport category aircraft. Be that as it may, dealing with the sudden loss of 60% - 80% of your available power is no cup of tea.

As we look at Part 23 certification criteria, we must consider that these are minimums. Some Part 23 aircraft can do better than the minimum requirement while others can't. We should know where our particular aircraft fits into the picture. This knowledge must be acquired much before we ever have to use it. Yes, you can get a "multi-engine rating" in less than 10 hours, but you sure can't learn what you really need to know.

It also does us well to think about the fact that "book values" are determined for "like new" aircraft, with everything functioning at its best. An "old" engine, turning an "old" prop on a "dirty" airplane is not likely to do as well as a shiny brand new airplane flown by a test pilot. You know, like the one they used to develop those "numbers".

Engine failure at cruise requires very different analysis and planning than does engine failure on take off. If managed well, and that's a big IF, most light twins will give you time to consider your options (if the terrain isn't too high) and probably one shot at a good single-engine landing on the airport.

On the other hand, engine failure on takeoff really doesn't give you any options that I would consider capable of eliminating the pucker factor. Maybe your airplane can climb at 50 FPM or even 150 FPM. Assuming that it can, consider this:

How long is it going to take you, with your climb rate, to reach an altitude that will allow you to manuever for a landing on the airport of departure? What was that density altitude again? Is the air smooth as glass ... or do you have to deal with turbulence too? What distance will you cover during that time? What will happen to your "climb rate" when you make a turn or hit a downdraft? What are the obstacles, obstructions, etc., between you and the final approach? Will you be able to climb over them or at least fly around them? What will your "pattern" altitude really be as you manuever for this approach/landing? Will you fly the pattern at 50 ft, 100 ft, 300 ft? How many times have you done that and how does it affect your judgment and ability to set up the approach? What if you don't get it "right" .... the first time? Should you climb into the overcast or manuever underneath it? If you do climb into it, can you get to the intial approach altitude? What will you do if you can't? Can you "miss" this approach? When will you lower the gear? What about the flaps? How good is the "good engine"? That's not the one with the questionable mag drop is it? How long will it run at max power? Should you really have feathered that propeller .... or could you do better by keeping it running at reduced manifold pressure? Did you really lose the engine .... or was it only the turbo charger? Finally, are you alone ... or is your airplane full of non-pilot passengers who just might not sit silently while you demonstrate your skill?

Two more questions ... when a single-engine aircraft has an engine failure on takeoff .... how many pilots have been able to make a 180 and land downwind ... what are the chances of that? When a light twin loses an engine on takeoff ... how many successful landings have resulted from climbing out and returning to the airport? I'll bet the stats are not very different from the 180 and downwind landing in a 172 (or whatever).

I doubt you'll find many good answers to those questions no matter which light twin you happen to fly. I also think you should have a pretty good idea of what the answers really are, today, on this takeoff, in the real world!

I would urge all of you to consider the problems before each and every departure and develop a "plan" of action that you can reasonably expect to follow successfully, then follow it. A sudden and unexpected engine failure is not conducive to planning. Given the marginal performance of light twins, you'll have your hands more than full just trying to fly the airplane if you should be unlucky enough to have that experience. If you have no advance plan, the outcome is seldom successful. Please consider that a controlled crash always has a better outcome than an out of control inverted landing or a head on collision with an obstruction.

No matter how good a "stick" you may happen to be, you can't make the airplane do anything of which it is incapable. Therefore, I suggest that you know the capabilities and conciously select the "lesser of evils". It has been said that any landing you can walk away from is a good one. That includes an off-airport landing when necessary.

That the countryside is not littered with the aluminum of light twins (or of single engine aircraft) is generally not attributed to the skills of their pilots or the performance capabilities of the airplane following engine failure. The good statistics are earned by the engineers and the mechanics, not the pilots. Thanks be to them, and the Almighty, catastrophic powerplant failures are very rare.

Neverthless, we need to prepare ourselves for those things that "almost never happen", better than we do for the routine. Meanwhile, if you can get into a T-category aircraft, by all means do it. The life you save may be your own.

Fly Safe.

 

[pilotshan]

I'm going by memory here, so take the info accordingly; here are the requirements:

MTOW < 6000 lbs, Vs1 < 61 knots: Recorded gradient of climb or descent at 5000 feet pressure altitude, standard day, clean configuration, inoperative engine windmilling.

Vs1 > 61 knots: Positive climb gradient of 1.5% at 5000 feet pressure altitude, standard day, clean configuration, inoperative engine windmilling.

MTOW > 6000 lbs: Positive climb gradient at 400 feet and 0.75% climb gradient at 1,500 feet. Takeoff power at 400 feet, MCP at 1,500 feet. Standard day, clean configuration, inoperative engine windmilling.
*Turboprops: Not only previous, but also capable of a 1.5% climb gradient at 5,000 feet pressure altitude, and 0.75% climb gradient at ISA +40 degrees F. Same configuration as above.

The correct conditions are: 5,000' pressure altitude, std. day, clean, max power on good engine, and critical engine feathered. All found in part 23.67.

I have about 300 hours of dual given in Piper Senecas (IV) and Seminoles so here is my insight (and I in no way claim to be an expert, just in a slightly more advanced stage of learning about these things than I was when I was a student):

-know what your airplane is capable of. The Seneca will happily climb to pattern altitude and fly you back to the runway with one engine out, the Seminole might not.

-know that when you lose an engine in a twin you lose 50% of your power, but 80% or more of your climb performance. These numbers are spelled out in a previous post on this thread (I believe they are directly from "Always Leave Yourself An Out", previously mentioned also), but here's what I use to drive that point home with the students:
The Seneca IV has 220HP/side, so with both engines running, you have 440HP available. It takes about 175 HP to maintain straight and level at max weight, leaving 265 excess HP to climb with. Not too bad. But, when you lose one engine, you cut your available HP in half to 220. The aircraft still needs 175 HP to maintain straight and level, leaving you with a measly 45 HP left to climb with. Not so great. Especially after you have to reduce the power to 200 HP because you're at your 5 min. limit for 220 HP.

-be aware of your surroundings. In a single, I'm always looking for the best place to make an off-airport landing. However, in a twin, I'm keeping track of the nearest suitable airport. That airport isn't always the closest, but the one with the runway long enough to minimize the chances of overshooting and a possible go-around. Because we all learned in our training that single engine go-arounds are not only bad, but in many cases, impossible. Crosswind factors also factor into our decision because we have enough to worry about without picking the runway with the 20 knot direct crosswind.

-realize that eventhough you may overshoot, it's always better to run into the fence at the end of the runway at 20 knots than it is to crash into the trees at 90 knots because you tried to execute a go-around.

-always remember that the only thing that second engine is really good for is flying you to your crash site.

"Always Leave Yourself An Out" and "Flying Light Twins Safely" are both excellent publications, which all of my students receive. For additional material, which has been very useful, do an internet search for "See How It Flies". It has a multi-engine chapter which is excellent, but the rest of it is very good also. I wouldn't reccomend it to students because it's somewhat technical, but instructors should find it informative.

Hopefully, this has been useful... my expanded 2 cents.

 

[172driver]

Not that it affects the overall point of this thread a whole lot but all of the previous statistics are a little misleading as far as Part 23 goes. The regulation for demonstration of climb performance changed in 1983 and only applies to twins certified after 8/18/83. As far as I know, no twins fall in that category.

For twins certified before 1983:

MTOW<6000 and Vso<61 stays the same. Climb/descent performance must be demonstrated.

MTOW>6000 OR Vso>61...Climb performance must be .027 x Vso squared in fpm @ 5000' on a std day.

Great post surplus. You hit it right on the head. Tough to get this point across flying brand new Seminoles, in flat Florida, in the winter, from 10,000 ft. runways. All we MEI's can do is teach it religiously on the ground and in the sim. Pound the dangers of a continued SE takeoff into their heads. Make them explain repeatedly what they would do if any one of those factors was different. Show them the different factors in the sim and make them evaluate performance before trying to continue. Teach decision making rather than rote procedures.