High Performance Twins

[gfvalvo]

My ME time is very limited and my training was in the relatively docile Seneca, so I'd like to pose a question to you high-time ME guys. What is it about the high-performance twins (421, MU2, etc) that can bite the inexperienced? Let's say the situation is losing one on take-off. The danger of this scenario was drilled into me from the beginning of ME training, so I assume all ME pilots know about it (at least in theory or abstractly). What makes the high-performance twins so much more dangerous for the inexperienced or non-proficient in this situation? Things I've thought of:

* Longer time being exposed to airspeeds between Vr and "blue line"

* High-performance twins react more "viciously" when they lose one on take-off

* Corrective action must be taken more quickly and inexperienced pilots react too slowly.

Also, let's say you've flown 5000 hours in one of these HP twins without every having an engine failure. You still don't have any "experience" in that department. What have you gained in that 5000 hrs that will save your butt the first time you do lose one on take-off?

Thanks.

 

[EagleRJ]

I don't know if higher performance twins are necessarily harder to fly than "training" twins. I think most of the accidents that happen to the faster twins are wealthy but low-time owners who allow themselves to get in over their heads. Any twin is more dangerous in the hands of an inexperienced and overconfidant pilot.

Most of the added complexity with aircraft like the C421 come from the additional workload from systems like turbochargers, pressurization, and more complicated avionics. Generally, most of the faster twins are no harder to fly, although like smaller twins, they are not required to have a positive single-engine climb rate. That means that you still need to know what your SE climb rate is, and plan accordingly if you lose an engine.
Of the light twins I've flown (PA-30, PA-34, PA-44, C-310, C-340, C-421), I can't any of them being especially difficult than the others, although some had higher landing speeds and were a little less maneuverable.

I don't have any MU-2 time, but I understand that the aircraft behaves a lot like a jet. It's in a different league from the other aircraft, being a turboprop and being a lot heavier. High takeoff and landing speeds, high power off sink rate, spoiler roll control, and the roll damping of tip tanks probably contribute to its reputation as a handful. A current MU-2 pilot would be better able to describe flying it.

 

[KeroseneSnorter]

Most of the people that you see flop one into the ground on a lost engine senario, turn out to be the type that got their ME 10 years earlier, and hasn't practiced single engine procedures since then.

Others fall into the catagory of trying to keep one flying that cannot possibly fly due to elevation, temperature, or weight. Instead of just taking a controlled off field landing, they try to keep it flying until they experience a VMC roll. Remember that light twins do not have to climb, or even hold altitude on one engine to be certified. Single engine performance is simply "recorded" for lack of a better word, during type certificate testing. So bottom line....Know your airplane and what it is capable of, and more importantly, know when it will not fly. Take a 310 or a Baron for instance. They will climb at gross weight (Slowly) at sea level, but if you lose one at gross weight in Denver during summer forget it. Pick a nice flat spot for a controlled off field landing.

The MU-2 is a whole different catagory. It had to climb on one engine to be certified. To that end, the numbers that are published in its flight manuals are hard numbers. Meaning that if you cannot meet the climb requirements for a certian runway length, weight, or temperature requirement, you are not legal to do it. (Not that this stops some people) But eventually the pilot that ignores the book will get bitten. Even with a turbine or jet, practice is the key word. That is why the insurance companies want recurrent once a year or more, and why part 135 and 121 PIC requirements call for a Prof. check every six months.

If you stay proficient, when it really does happen, it is kind of like riding a bike, you just do what is needed without really thinking about it. Every failure that I have had, I can tell you what things looked and felt like, but I do not remember actually doing the emergency procedures, they just happened. Kind of like Pavlov's dog I guess. A conditioned response to external stimuli. (There, I knew that Psyc. degree would come in handy!!!)

Of course, This is all just my take on it. I am sure everybody has their own thoughts.

 

[mmmdonut]

Well I'll just share a few things from my experience. I did most of my ME training in a Seminole which is basically just a Cherokee on crack... it had terrible performance. It was pretty easy to fly and you didn't need to think much when flying it.

Then when I flew the Baron I learned that I needed to plan my descents a little better so I could get down and slow down... something you're not used to with the PA-44. The Baron was also a "real twin" in that an engine failure on TO wasn't the worst thing as you'd still be able to get 500 fpm out of it.

With the Seminole I was lucky to see 50-100 fpm.

Procedurally everything is the same.

 

[apcooper]

I would agree with a lot of the above posts. The larger twins like the Baron are EASIER than a Seminole to handle an engline failure in. You will get almost 400fpm gross at SL in a Baron 58. If you lose one before VMC-easy, just chop both throttles immediatly. Actually in any piston twin if I lost one below blue line I'd land straight ahead just like a single unless very light and flying near sea level in arctic cold! I'd much rather make a controlled crash that kill myself in a big fireball from a VMC rollover. Also Just after rotation if one goes you probable WILL NOT be able to react fast enough. Even in a simulator when you are EXPECTING it, it is still difficult just after liftoff!! If past blue line and one goes out PITCH FOR VYSE and accept WHATEVER climb or descent you get. Feather the offending prop quickly BUT make D#mn sure you don't feather the good one!!!

Turboprops eventhough more complex overall than piston twins are easier in this regard since many have autofeather that you engage before T.O. Jets are even easier since you have nothing to feather and will be covered every inch of the way due to ballanced field requirements. I wish piston twins had a fuel jettison button like jets so instead of 100fpm climb you could get 400fpm and then return for a single engine landing.

I would like to add at the risk of starting a big fight that I firmly believe that a twin is SAFER than a single for all but a 10 second window near liftoff ASSUMING a pilot can handle an engine out in his sleep! Even if at cruise and you are flying above terrain that is higher than the SE ceiling, the very slow driftdown will probably allow you to land at an airport assuming you do everything right. Hope this helps.

 

[Vik]

Did you enjoy landing the PA-30? I love it!!

I don't know if higher performance twins are necessarily harder to fly than "training" twins. I think most of the accidents that happen to the faster twins are wealthy but low-time owners who allow themselves to get in over their heads. Any twin is more dangerous in the hands of an inexperienced and overconfidant pilot.

Most of the added complexity with aircraft like the C421 come from the additional workload from systems like turbochargers, pressurization, and more complicated avionics. Generally, most of the faster twins are no harder to fly, although like smaller twins, they are not required to have a positive single-engine climb rate. That means that you still need to know what your SE climb rate is, and plan accordingly if you lose an engine.
Of the light twins I've flown (PA-30, PA-34, PA-44, C-310, C-340, C-421), I can't any of them being especially difficult than the others, although some had higher landing speeds and were a little less maneuverable.

I don't have any MU-2 time, but I understand that the aircraft behaves a lot like a jet. It's in a different league from the other aircraft, being a turboprop and being a lot heavier. High takeoff and landing speeds, high power off sink rate, spoiler roll control, and the roll damping of tip tanks probably contribute to its reputation as a handful. A current MU-2 pilot would be better able to describe flying it.

 

[BD King]

A number of guys that I know, mentally go through engine out proceedures right before standing the throttles up. Not me. I have a little prayer which goes " Dear God, let both of these mothers run for the next two minutes".

 

[KeroseneSnorter]

A number of guys that I know, mentally go through engine out proceedures right before standing the throttles up. Not me. I have a little prayer which goes " Dear God, let both of these mothers run for the next two minutes".

I noticed that you have DC-3 listed in your aircraft column...........that would explain the prayer!!!

I never flew the 3. However it was my Dads first airline job back in the mid 60's. He always said that if you made a full month without one quitting, that was something to talk about. And to think that passengers now complain when they have to ride an RJ instead of a 737.

 

[BD King]

I noticed that you have DC-3 listed in your aircraft column...........that would explain the prayer!!!

I never flew the 3. However it was my Dads first airline job back in the mid 60's. He always said that if you made a full month without one quitting, that was something to talk about. And to think that passengers now complain when they have to ride an RJ instead of a 737.

Ahh. Dad and myself must be about the same age. My 3 time is all corporate. If you Dad was flying the line in the mid-sixties in a 3 it had to be Ozark or Lake Central, or something similiar........You are right. If the RJ was around 40 years ago, people would have been thrilled.......Engine failures, I've had seven, but none of the engines were round....This may make a good thread. "My favorite engine failure".

 

[FN FAL]

I don't care which plane is easier to fly, lower time and low recency time pilots are susceptible to making certain kinds of decisions. That doesn't mean that high time or recent pilots don't make bad decisions, but....

NTSB Identification: CHI01FA329.
The docket is stored in the Docket Management System (DMS). Please contact Public Inquiries
14 CFR Part 91: General Aviation
Accident occurred Saturday, September 29, 2001 in Marshfield, WI
Probable Cause Approval Date: 11/25/2003
Aircraft: Cessna 414 Riley Super-8, registration: N414NG
Injuries: 3 Fatal.The airplane was destroyed after an attempted landing following a reported partial power loss of the left engine while en route. The flight did not divert to the closest airport located about 27 nautical miles to the southwest while at an altitude of about 15,900 feet. This airport was a controlled field equipped with airport rescue and fire fighting (ARFF), and its longest runway was 9,005 feet. The flight diverted to the departure airport located about 93 nautical miles to the north. This airport was an uncontrolled field not equipped with ARFF, and its longest runway was 5,000 feet. No emergency was declared.

The airplane was reported by a witness to be too high and too fast to land on runway 34 at the airport. The winds were from 140 degrees at 6 knots. The wreckage distribution was consistent with an impact resulting from a Vmc (minimum control speed with the critical engine inoperative) roll to the left.

The pilot received a checkout from the right seat in the accident airplane by the airplane owner. The checkout was about 20 minutes in duration and did not include any single-engine flight maneuvers or emergency procedures. The owner did not hold a certified flight instructor certificate. The pilot had stopped flying for 12 years and just began giving flight instruction and flying in single-engine airplanes about a year prior to the accident. The pilot's recent multiengine flight experience was limited to a couple of non-revenue flights within the past year while seated in the right seat of a King Air. The King Air was used for commercial charter work which would involve one or two landings per flight. One landing was made on the day prior to the accident. The accident pilot asked the King Air pilot to accompany him along on the accident flight; the King Air pilot declined. A multiengine commercial rated pilot-rated passenger, who the accident pilot knew, was seated in the right front seat.

 

[FN FAL]

It's not just low time pilots that are susceptible to problems with high performance twins....

CHI03FA138HISTORY OF FLIGHT

On May 25, 2003, at 1754 central daylight time, a Piper PA-31P, N36DR, piloted by an airline transport pilot, sustained substantial damage when it impacted trees and terrain after takeoff from runway 36 (5,150 feet by 100 feet, asphalt), at the Lakeland Airport/Noble F. Lee Memorial Field (ARV), near Woodruff, Wisconsin. The airplane was consumed by fire subsequent to the impact. The 14 CFR Part 91 flight was operating in visual meteorological conditions and an instrument rules flight plan had been filed but not activated. All four occupants of the airplane were fatally injured. The flight was originating at the time of the accident. The DuPage Airport (DPA), West Chicago, Illinois, was the intended destination.

The airplane was reported to have been flown from DPA to ARV by the pilot and pilot rated passenger in order to pick up two passengers and return to DPA.

The airplane impacted into level wooded terrain about 1/2 mile north of the departure end of the runway and left of the extended runway centerline.

A witness who is a pilot reported seeing the airplane "hardly climbing at 60+- feet just above the [runway] 18 threshold. At this point he was making some power and no engine abnormalities or prop sounds were heard. The plane was very slow with a 5 [degree] pitch up then I saw the nose leveled and I knew he was in serious trouble. I saw the plane going straight for a few more seconds then lost sight. I listened as I ran to my truck. I then heard it hit the trees and impact."

Another witness reported seeing the airplane take-off. He reported that the sound was not normal and that this is what drew his attention to the airplane. He said that the airplane sounded labored. He reported that the airplane was not gaining altitude as expected and the airplane was much lower than he was accustomed to seeing. He stated that he lost sight of the airplane due to obstructions to his view. He stated that from the time the airplane drew his attention, to the time the airplane started hitting the trees, the engine sounds did not change.

PERSONNEL INFORMATION

The pilot held an airline transport pilot certificate with ratings for multi-engine land airplanes with commercial privileges for single engine land airplanes. The pilot was type rated in Boeing 757, Boeing 767, McDonnell Douglas DC-9, and Cessna 500 series aircraft. The pilot also held a flight engineer certificate for turbojet-powered airplanes and a flight instructor certificate with a rating for single engine airplanes. The pilot's flight logbook was not recovered. The pilot served as a chief pilot for a major airline. According to airline records, the pilot had accumulated 8,524 hours of flight time in Boeing 767 and McDonnell Douglas MD-80 aircraft. An airline representative estimated that the pilot also had approximately 4,000 hours in Boeing 727 aircraft. The Boeing 727 flight time was estimated since the airline no longer maintains flight records for that airplane.

The pilot's first class medical certificate was issued on February 3, 2003, with the limitation, "Must wear corrective lenses." The pilot reported having 11,850 hours of flight experience as of the date of his medical certificate.

Training records obtained during the investigation show that the pilot received 11.0 hours of ground training and 3.0 hours of flight training in the accident airplane on October 7, 2002. The records indicate that engine-out procedures and engine-out approach and landings were performed. The training records indicate that Vmca demonstration was not performed. Vmca refers to the minimum airspeed in flight at which directional control can be maintained, when one engine is made inoperative.

The right seat passenger was also a pilot. The passenger held an airline transport pilot certificate with ratings for multi-engine land airplanes with commercial privileges for single engine land airplanes. The passenger was type rated in Boeing 727, Boeing 757, Boeing 767, and Lockheed L-382 series aircraft. The passenger also held a flight engineer certificate for turbojet-powered airplanes. The passenger's flight logbook was not recovered. The passenger had previously served as a chief pilot for a major airline prior to his retirement in 1999. According to airline records, the passenger had accumulated 2,473 hours of flight time in Boeing 767 aircraft. An airline representative estimated that the passenger also had approximately 7,000 hours in Boeing 727 aircraft and 3,000 hours in Boeing 707 aircraft. The Boeing 727 and Boeing 707 flight time was estimated since the airline no longer maintains flight records for those airplanes. The airline representative also indicated that the passenger had an additional 500 hours in Boeing 727 airplanes as a result of flight activity for a travel club after his employment with the airline.

The passenger's first class medical certificate was issued on April 25, 2003, with no restrictions. The passenger reported having 15,682 hours of flight experience as of the date of his medical certificate.

METEOROLOGICAL INFORMATION

The departure airport automated weather observation system recorded the weather at 1753 as: Wind 020 degrees magnetic at 7 knots gusting to 15 knots; Visibility 10 statute miles; Sky condition clear; Temperature 19 degrees Celsius; Dew point -8 degrees Celsius; Altimeter setting 30.09 inches of mercury.

WRECKAGE AND IMPACT INFORMATION


...The left wing was damaged by impact and fire. The majority of the wing structure was consumed by fire. The aileron and flap were identified. The aileron control sector was found with both cables attached. Both cables were continuous to the center fuselage area where both cables were broken. Both of the cable breaks exhibited signatures consistent with overstress. The flap actuator was found in the fully retracted position. The left fuel selector valve was found positioned to the inboard main fuel tank. The crossfeed selector valve was found in the off position...The right fuel selector valve was found positioned to the outboard auxiliary fuel tank.

...The right propeller blades exhibited leading edge damage and chordwise scratching. The blades also exhibited bending and twisting opposite to the direction of rotation. The propeller spinner was crushed and twisted opposite to the direction of rotation.

...The left propeller remained attached to the drive gear from the engine. No evidence of rotation was noted with respect to the propeller, propeller blades, or propeller spinner. The left engine and propeller were retained for further examination. (See "Tests and Research" section of this report.)

Several tree limbs and tree trunks were found in the immediate vicinity of the wreckage that exhibited diagonal cuts. The cut pieces of trees were found predominately on the right side of the wreckage path.

On-scene examination revealed no anomalies with respect to the airframe, right engine, or right propeller that could be attributed to a pre-impact discrepancy.

MEDICAL AND PATHOLOGICAL INFORMATION

The results were negative for all tests performed.

TESTS AND RESEARCH

Examination of the

engine's internal components revealed no mechanical discrepancies that could be attributed to a pre-existing condition. No evidence of a pre-impact failure was found.

Examination of the left propeller ...found no condition that would have prevented normal propeller operation.

The Powerplant Engineer's Factual Report of the engine and propeller examination is included in its entirety in the public docket associated with this accident report.

The "Before Take-off" checklist contained in the FAA approved Airplane Flight Manual (AFM) for the PA-31P includes a line-item to set the fuel valves to the inboard tanks. The AFM further states in the section titled "Systems Operation And Checks";

10. FUEL MANAGEMENT
a. Inboard tanks must be selected for take-off and landing
b. Inboard tanks may be used for all phases of flight (takeoff, climb,
cruise, descent and landing)

NOTE
Since inboard tanks must be used for landing, it is essential that
fuel usage be planned to retain a reasonable quantity of fuel in the
inboard tanks (in the event of a balked landing) for go-around and
subsequent normal landing.

c. Outboard tanks may be used for climb, descent or level flight when
outboard tanks are more than 1/2 full. Outboard tanks may be used
only for level flight when quantity is 1/2 or less.

The straight line distance from DPA to ARV is 287 statute miles. According to the ARV airport manager, no fuel was obtained for the return flight from ARV to DPA.​

​

 

[Tinstaafl]

gfvalvo, other factors that can differentiate 'typical' training twins from larger things:


* Relatively large changes in mass between light weights & max. Can affect handling eg attitudes for particular speeds, responsiveness.
* More complex systems eg turbocharged engines need more time to respond to throttle movements, fuel systems that aren't as intuitive, aircon that robs power, hydraulic systems needed to operate flap &/or gear &/or nosewheel steering (bad luck if there's only a single hydraulic pump - and it's on the failed engine...) etc
* Some types have a significant performance penalty while gear is cycling eg C337
* Faster so not as much time to recognise events, think & react, couple with
* More mass so more inertia ie longer to respond to control inputs


Some have uncommon (for light aircraft) design characteristics eg the MU2 only uses spoilers for roll control (plus very small 'ailerons' for roll trim - and only for trim). If - while coping with an engine failure - the pilot uses aileron to counter the adverse roll then there will be a performance penalty due to the drag/loss of lift caused by the roll spoiler. Bear in mind that roll spoilers are supposed to cause loss of lift & added drag.

 

[BD King]

gfvalvo, other factors that can differentiate 'typical' training twins from larger things:


* Relatively large changes in mass between light weights & max. Can affect handling eg attitudes for particular speeds, responsiveness.
* More complex systems eg turbocharged engines need more time to respond to throttle movements, fuel systems that aren't as intuitive, aircon that robs power, hydraulic systems needed to operate flap &/or gear &/or nosewheel steering (bad luck if there's only a single hydraulic pump - and it's on the failed engine...) etc
* Some types have a significant performance penalty while gear is cycling eg C337
* Faster so not as much time to recognise events, think & react, couple with
* More mass so more inertia ie longer to respond to control inputs


Some have uncommon (for light aircraft) design characteristics eg the MU2 only uses spoilers for roll control (plus very small 'ailerons' for roll trim - and only for trim). If - while coping with an engine failure - the pilot uses aileron to counter the adverse roll then there will be a performance penalty due to the drag/loss of lift caused by the roll spoiler. Bear in mind that roll spoilers are supposed to cause loss of lift & added drag.

Like I said,"Dear God, let both of these Mothers run for two minutes."

 

[sky37d]

Like I said,"Dear God, let both of these Mothers run for two minutes."

Just another reason to fly a C337. Skymaster, CLT

 

[Lead Sled]

Most pilots fail to remember the simple fact that most (read: EVERY) piston twin has two engines because it needs two engines AND it is only capable of maintaining sustained, controlled flight on one engine under certain limited conditions. The twins that are flown in training are really no better or worse than “high performance” twins – it’s just that in the training environment, engine failures are carefully choreographed exercises; not the totally unexpected “What the hell just happened?” events that engine failures are in the real world.

Single-engine performance in any piston-powered multiengine is abysmal. Loss of power is the primary culprit. Remember, normally aspirated aircraft lose power with altitude. An aircraft's climb ability is directly proportional to the amount of "excess" power that it has available vs. what is needed to maintain level flight. For example, if a 200 HP normally aspirated airplane requires 100 HP to maintain level flight it would (at SL, ISA day) have 100 "excess" HP to use for climb. At 10,000' MSL, the engine might only be able to produce 130 HP, leaving it with a 30 HP surplus. This is the reason why turbocharged aircraft perform so well - you would be able to maintain SL power up until you reached the "critical altitude" for the particular engine. In some cases, this can be as high as 18,000' MSL.

This is also why light twins typically perform so poorly on one engine. Take, as an example, a Twin Comanche with two 160 HP engines. If that airplane required, say, 150 HP to maintain level flight it would have 170 "excess" HP to climb with. If it lost an engine, it would have lost 50% of its available power, but with just 10 "excess" HP, it may have lost 95% of its ability to climb.

In order to be competitive in today’s market, manufacturers are basically forced to design aircraft that just barely meet certification requirements. Too much performance simply means that you could carry more weight (passengers and/or fuel). This concept is driven home when you look at the various STCs that are out there to modify some of the more popular twins – bigger engines and VGs provide for much better performance, but along with the installations usually comes gross weight increases that reduces the performance back to the original certification levels. In other words, with the STCs you still have a marginal performing airplane – it’s just that know you have a 6,300 pound marginally performing airplane instead of a 6,000 pound one.

As has been mentioned, there is a window of exposure, right after takeoff in twins where you’ve got your fanny hanging out if you were to lose an engine. In the case of most piston twins, their ability to maintain controlled flight depends upon the pilot getting the gear up, the propeller feathered, and the flaps up. Failure to this often results in the airplane being turned into a lawn dart.

We tend to take engine reliability for granted, but I believe that this is a very dangerous thing to do. Most light twins simply won't maintain altitude with a windmilling propeller and/or the gear down. The old Metroliners had a rocket bottle in the tail to buy the flight crew enough time to get the gear up in the wells. Auto-feather systems are on most, if not all, turboprop twins. The manufacturers wouldn't put up with the increased costs and complexity of doing this if there wasn't a true need for it. They put this stuff on the turboprops that have significantly better single-engine performance than piston-twins. It really ought to be on the "little" twins, but no one is willing to pay for it.

Like I said, light twins lose up to 90%+ of their climb capability. The figure is probably even higher than that - I've seen several non-turbo'd twins that wouldn't climb out of ground effect and several turbocharged twins that could barely achieve climb rates of 100 fpm or so. But never the less, the point is that twin engine aircraft have two engines because they need two engines and under certain conditions they can maintain controlled flight on one engine IF THE PILOT DOES EVERYTHING RIGHT. You don't have time to dawdle; it has to be done right and right now.

Don't assume that pilots flying light-twins are fully qualified and proficient in their multi-engine aircraft. Unfortunately, VERY few light-twin pilots are. I know, I've given too many BFRs and ICCs to owner-flown light twins. Typically, they are usually very rusty and very dangerous. They don’t get enough initial and on-going recurrent training. Believe me; it usually takes much longer than the basic 1 hour BFR to bring these people up to speed. The sad part is many of these people have more money than sense and they simply don't fly enough to stay on top of things and the accident record proves it – statistically, you stand a much better chance of surviving the loss of an engine in a single than in a light twin. Oh well, that's another topic... Bottom line is that it's this type of pilot that skews the statistics, not the well-trained, experienced professional (or amateur).

Part 23 airplanes (light aircraft) have no guarantees when it comes to takeoff performance as large turbojet-powered aircraft have. Although some manufacturers publish accelerate/stop and accelerate/go charts for their light aircraft, these charts really don't pertain to the discussion. (The charts for the large aircraft provide for a certain minimum level of performance, the charts for light aircraft only provide for the aircraft to become airborne – not for obstacle clearance.) If the pilot persisted in his/her foolishness and insisted in operating a light twin out of an inappropriate airport no one would ever care until the eventual accident occurred, at which point, I’m sure the FAA would want to talk to the pilot (if he survived) about why he had chosen to violate FAR 91.13 (Careless and Reckless Operation) among several other potential violations.

The airline guys have it easy – they always operate off of adequate runways at weights that ensure adequate performance, in the event of an engine failure, to clear all known obstacles and successfully complete the takeoff. If they can’t do that, they don’t go. Period. They also have people, whose job function it is, to feed them the data that allows them to do it. Corporate jets are also required to be operated that way, but we have to fend for ourselves when it comes to calculating our takeoff performance and limitations. Pilots of light twins are flying the most demanding aircraft in the sky. One of aviation’s little secrets is that the larger the airplane the easier it is to fly. Light twin pilots have to be at the top of their game; the problem is that many of them aren’t.

That's why it's really the insurance companies that control who gets to fly the larger, more complex aircraft - not the FAA. Although practically anyone with enough money in their wallet to pay for the training can get a rating, it's only those with the necessary experience can get the insurance afterwards to use it. Bottom line is when you "step up to the plate" and start flying larger, more complex aircraft you have a whole lot more things to consider. You are also playing for higher stakes - the consequences of screwing up are usually much higher.

I also want to remind those new ME pilots out there that there are those who advocate the philosophy that "if we loose an engine, we'll just close the other throttle and land straight ahead - just like if we were in a single." That's fine, and in many cases, it’s a viable option. However, you need to consider the effect that the heavier weight of most multiengine aircraft has on the survivability of an off field landing...

The FAA mandates that most certified single engine aircraft have a stalling speed no greater than 61 knots. There is no such requirement for multiengine aircraft. A few multiengine aircraft are light enough to come in with a stall speed less than 61 knots, but many designers will take the opportunity to take advantage of higher wing loadings to increase a light twin’s performance. What you end up with is aircraft with stall speeds significantly higher than the equivalent single engine airplane. Take the Beech A36 Bonanza and the Baron 58. Essentially, they are single and multiengine versions of the same airplane, with more or less comparable performance and capabilities. The Bonanza has a stall speed of 59 knots and the Baron, a stall speed of 73 knots.

So, what’s my point? If you double the stall speed, you multiply the kinetic energy four times. The survivability of a crash is a function of how quickly the kinetic energy is dissipated. What you end up with is a scenario where, in the event of an off field landing in a twin, you have nearly twice the kinetic energy to dissipate. If you’re lucky you’ll have a flat smooth surface, but throw in some rocks, trees, etc. and you quickly see why survivability is a big question.

So what if a lot of people operate their aircraft in a way that that leaves them “exposed”? Let’s assume that they have done it for hundreds or thousands of hours and have never had a problem – does this mean that the operation is safe or are they merely lucky? What do you think? You can fail to plan for your eventual engine failure and place your trust in the laws of probability. But remember, if you choose this path, the danger doesn’t go away, it merely lies in wait and when the inevitable occurs, the laws of physics (and gravity) take precedence.

Oh well, I’d better get off of my soapbox before you guys knock me of it.

Merry Christmas

‘Sled

 

[Tinstaafl]

I think it's a very important point you make about light m/e asymmetric performance & handling. I always taught my students that conceptually a light multi was really a single engine aircraft, but with half the 'single' engine's cylinders mounted here, and the other half mounted over there.

In other words all that's been done is limit an engine failure to a the equivalent of a partial failure in a single instead of a complete stoppage. A Cessna C336/337 is a good example. A failure in one of these is near-as-dammit the same as a partial failure in a single.

Think of a V8 in a car with one bank of cylinders bolted over on one side of the engine bay and the other bank mounted on the other side of the bay. If one bank fails then what's left of the mechanicals might have enough power to continue driving, but in many situations it will not eg heavy, towing something, up a hill, brakes dragging, at a high speed, in summer in Death Valley etc.

Similarly with a light twin. The remaining cylinders & mechanical bits might have enough oomph but not a chance if there's excess drag, wrong speed, wrong altitude or temperature etc

What makes the typical asymmetric light twin worse than a single - apart from the additional kinetic energy if crashing - is the abysmal and even outright dangerous handling qualities. No aircraft would be certified if those were its normal handling qualities.

Of course competent handling by the pilot can neutralise the bad points but it takes continued attention to prevent it all turning to worms, and recent & sufficient practice to have the necessary skill.

 

[FN FAL]

I think it's a very important point you make about light m/e asymmetric performance & handling. I always taught my students that conceptually a light multi was really a single engine aircraft, but with half the 'single' engine's cylinders mounted here, and the other half mounted over there.

That's great and all that...but if you lose an engine in a piston twin, you lose 80%, not 50%. Half isn't over there and half over there when you lose one of those engines...20% is over there and nothing is over there.

Light twins are not certified to hold altitude on one engine, much less climb...they will hold heading if you have sufficent airspeed though. Having sufficent airspeed means accepting a descent rate in a lot of cases.

I have a friend that's been flying commercially for over 15 years, he thinks you pick an IFR alternate in case the weather at your destination goes below minimums...maybe you and him can go have coffee and share hangar flying stories sometime?

 

[Tinstaafl]

I didn't say that you lose half the performance. I said you lose half your engine and that what power is left may or may not be sufficient to maintain flight.

Try reading it again. Let me know when you go for coffee & hangar stories with your friend...

 

[FN FAL]

I didn't say that you lose half the performance. I said you lose half your engine and that what power is left may or may not be sufficient to maintain flight.

Try reading it again. Let me know when you go for coffee & hangar stories with your friend...

who cares about half the engines...performance is all that matters.

My wife was talking to the pizza place tonight as she ordered a pizza, she says, "you want a medium or a large?"

I said, "What the fu<k does medium or large mean?"

50%, 80%, 100%...who gives a rats ass right? If American Airlines can't put Chief pilots out that can fly Chieftans...do I really want to go there?

 

[Lead Sled]

In other words all that's been done is limit an engine failure to a the equivalent of a partial failure in a single instead of a complete stoppage. A Cessna C336/337 is a good example. A failure in one of these is near-as-dammit the same as a partial failure in a single.

In theory it sounds good. The only problem is that the safety statistics for all of the various Skymaster varients don't bare it out - they're as bad as for any other light twin.

'Sled

 

[KeroseneSnorter]

If American Airlines can't put Chief pilots out that can fly Chieftans...do I really want to go there?

What a lot of the airline guys forget is that being current in a large jet and being current in a light twin are two different things. Airline guys after not having flown a light airplane for a while always flare high, don't want to slow down, and look down searching for a TCAS screen before looking out the window when ATC calls out traffic. (One of the side effects of TCAS.)

You can't take your PC check at the airline and expect to be proficient in a light twin. Unfortunatly some of the guys forget this. Plus a guy that works the office such as an airline chief pilot and only flys a couple of trips a month is normally weak in his airliner also. No fault of his own, just a side effect of his job. We used to have a CP that would tell you flat out, "I do not get to fly much, so watch me and don't let me do something dumb" He was the best CP I ever worked for. Knew his strentghs and weaknesses, and would always back his pilots and their decisions in the cockpit against the company if it was a safety issue. Too bad that so many of them are yes men now.

As far as the single, multi discussion. If you just look at the NTSB data, on the surface it appears that the multis have a much higher death rate in an engine failure situation. What most people forget is that the NTSB does not track or even record the engine failures in twins that result in a safe landing. So the data is skewed. 121 is the only real data on single engine info that is tracked.

 

[Sniper Bob]

My wife was talking to the pizza place tonight as she ordered a pizza, she says, "you want a medium or a large?"

I said, "What the fu<k does medium or large mean?"

Then you smacked her good and told her to get her ass back in the kitchen, right?

jerk.

 

[Tinstaafl]

FN FAL, the point of comment is to dissuade the unfortunately common notion that light twins have some guaranteed flight capability purely as a result of the second engine ie that they are a 'true' multi engine a/c - which they are not. After that then it seems we're in heated agreement.

KeroseneSnorter, the NTSB may not track 'succesful' engine failures ie no accident occurs as a result, however that's not the case for other country's equivalents. Australia & the UK's equivalents do track those things. I think it's reasonable to assume that, since the safety outcomes for comparative tracked data is pretty much the same, that this also applies to areas where there are 'holes' in NTSB data.

I recall when Australia's CASA was considering approving SE turbine for public transport IFR that the data they had indicated that fatality rates for engine failure in a single was less likely to result in death from the inevitable forced landing/crash compared to light twins where a failure was less likely to result in a forced landing/crash however if it did then the fatality rate was greater.

Their conclusion was that the overall safety rate was equal or better for the SE turbine compared to light twins and moved quite quickly after that to approve SE turbine for public transport.

 

[jetdriven]

I sat in an MU-2 once and chatted with the pilot. You rotate at 100 KIAS and blue line was 151 KIAS. On one engine you cant climb with the gear down, and you cant retract the flaps in a turn. the gear doors are huge and add lots of drag in transit.

I asked him what do you do if you lose an engine below 151. He said "you crash."

At high density altitudes the Be-55 baron I used to fly wouldnt climb at all above about 5000 feet. At Santa Fe or ABQ I would have rather had a Bonanza. It was undeniably safer, with one-half the chance of engine failure, slower speed in a forced landing, a IO-550 out front to bear the brunt of the impact energy, and less total impact energy to deal with.

In the 1900 its quite easy. At 15,000 lbs if you lose an engine on takeoff you have autofeather and rudder boost. Plus the airplane for a short time will climb with the gear down. With the gear up it makes about 700-1200 FPM climb. Just spin the rudder trim knob, verify the failed engine has feathered, and return for landing. You can also initiate a SE goaround from 300 AGL with full flaps, something no piston twin Iam aware of can do, maybe the Ce-320 or Be-56TC.

In a skymaster good luck trying to identify the failed engine. Sometimes oil pressure oir fuel flow is the only indicator.

Most of the people that you see flop one into the ground on a lost engine senario, turn out to be the type that got their ME 10 years earlier, and hasn't practiced single engine procedures since then.

Others fall into the catagory of trying to keep one flying that cannot possibly fly due to elevation, temperature, or weight. Instead of just taking a controlled off field landing, they try to keep it flying until they experience a VMC roll. Remember that light twins do not have to climb, or even hold altitude on one engine to be certified. Single engine performance is simply "recorded" for lack of a better word, during type certificate testing. So bottom line....Know your airplane and what it is capable of, and more importantly, know when it will not fly. Take a 310 or a Baron for instance. They will climb at gross weight (Slowly) at sea level, but if you lose one at gross weight in Denver during summer forget it. Pick a nice flat spot for a controlled off field landing.

The MU-2 is a whole different catagory. It had to climb on one engine to be certified. To that end, the numbers that are published in its flight manuals are hard numbers. Meaning that if you cannot meet the climb requirements for a certian runway length, weight, or temperature requirement, you are not legal to do it. (Not that this stops some people) But eventually the pilot that ignores the book will get bitten. Even with a turbine or jet, practice is the key word. That is why the insurance companies want recurrent once a year or more, and why part 135 and 121 PIC requirements call for a Prof. check every six months.

If you stay proficient, when it really does happen, it is kind of like riding a bike, you just do what is needed without really thinking about it. Every failure that I have had, I can tell you what things looked and felt like, but I do not remember actually doing the emergency procedures, they just happened. Kind of like Pavlov's dog I guess. A conditioned response to external stimuli. (There, I knew that Psyc. degree would come in handy!!!)

Of course, This is all just my take on it. I am sure everybody has their own thoughts.

 

[Lead Sled]

I sat in an MU-2 once and chatted with the pilot...I asked him what do you do if you lose an engine below 151. He said "you crash."

I've sat in MU-2s too - over 1000 hours worth - and your pilot friend was being a little dramatic. The MU-2 has its quirks, but it is a safe airplane. It only demands that it be flown properly when an engine is lost. The problem is that it is "jet like" and has a definate profile that must be flown after an engine failure. The MU-2 has the same wing loading as a B-727, T-38, and Lear; if you try to fly it like a King Air or Seneca, you'll probably turn it into a lawn dart. Personally, I would never fly in an MU-2 unless the pilot had been trained in the sims at FlightSafety.

'Sled

 

[BD King]

Lot's of good information on this thread, but I will repeat for the third time, when ya stand them up, ya pray Dear God let the mothers run for two minutes. Period. .....I am not Bob Hoover. I could be (as most of the board could be), but that takes a different mind set. It takes time and that takes money. We depend on those pissy Continentals and Lycomings to keep running. I have had seven engine failures. I DO NOT trust them. They will quit.........I can anticipate the failure at rotation, but I still ask that the Mothers run for two FICKING minutes.

 

[FN FAL]

Then you smacked her good and told her to get her ass back in the kitchen, right?

jerk.

Actually, I do 60% of the cooking and 70% of the grocery shopping and I don't smack my wife. She has her own P-22 equiped with an NFA registered suppressor...so I have to be vewwy vewwy carefull.

 

[FN FAL]

...As far as the single, multi discussion. If you just look at the NTSB data, on the surface it appears that the multis have a much higher death rate in an engine failure situation. What most people forget is that the NTSB does not track or even record the engine failures in twins that result in a safe landing. So the data is skewed. 121 is the only real data on single engine info that is tracked.

Yes, the data is skewed...

However, when looking at off airport landings after engine failure in twins v. singles, singles win hands down.

P.S. They don't document how many singles make it safely back to airports after an engine failure either. I landed deadstick twice in single cessnas and a third was almost a dead stick...the engine died in the flare. All mechanical failures. In 1,700 hours of flying Multi's...I only had one failure of a prop control, resulting in not being able to reduce RPMs and one broken intake valve spring...resulting in odd running engine, but not a complete failure.

I came real close to losing a turbine engine in a PT-6 powered caravan once, but I can only speculate, because I don't know how fast the oil was leaving the airplane and I don't know how long a PT-6 will run without oil. After a two hour trip I landed with the belly soaked in turbine oil and only had a couple quarts out of fourteen remaining. Needless to say, I didn't account for this in my weight and balance, since I didn't know I was going to have to work a weight shift problem...there was no indication of oil loss observed in the cockpit.

 

[KeroseneSnorter]

I sat in an MU-2 once and chatted with the pilot. You rotate at 100 KIAS and blue line was 151 KIAS. On one engine you cant climb with the gear down, and you cant retract the flaps in a turn. the gear doors are huge and add lots of drag in transit.

I asked him what do you do if you lose an engine below 151. He said "you crash."

At high density altitudes the Be-55 baron I used to fly wouldnt climb at all above about 5000 feet. At Santa Fe or ABQ I would have rather had a Bonanza. It was undeniably safer, with one-half the chance of engine failure, slower speed in a forced landing, a IO-550 out front to bear the brunt of the impact energy, and less total impact energy to deal with.

In the 1900 its quite easy. At 15,000 lbs if you lose an engine on takeoff you have autofeather and rudder boost. Plus the airplane for a short time will climb with the gear down. With the gear up it makes about 700-1200 FPM climb. Just spin the rudder trim knob, verify the failed engine has feathered, and return for landing. You can also initiate a SE goaround from 300 AGL with full flaps, something no piston twin Iam aware of can do, maybe the Ce-320 or Be-56TC.

In a skymaster good luck trying to identify the failed engine. Sometimes oil pressure oir fuel flow is the only indicator.

As mentioned before, the 1900 is a part 25 certified airplane so it is not in the same class as a 320 or Baron. Your 1900 has guaranteed performance, and as long as you fly it inside its legal envelope, it is supposed to give you the performance listed. Barring any structural failure or failure to feather, or auto feather it's performance on one engine, by definition, must be predictable and positive. Light twins do not have to conform to these restrictions. They are not required to "go" on one engine, and in many situations, they cannot go on one.

In my opinion, this is why you see a higher multi engine fatality rate in off field landings. Instead of accepting that the airplane is incapable of flying on one for whatever reason (temp., weight, Den altitude, or whatever) the pilots try to keep one flying past where they should. And end up with a VMC problem along with the off field landing issues.

It still comes down to proficiency, know your airplane and what it can do. This applies to single engine, ice, x-wind, whatever. I have had enough real failures in twins to know that you do not just die, as some in the aviation community suggest. I have not yet had to put a twin down on anything other than a concrete runway after I have lost an engine. And only one was anywhere close to an off field landing. I was on top when the engine failed, and picked up some ice during the drift down to SE ceiling. I even told the controller that It was doubtful that I would make the field and that I was planning an off field arrival. As fortune would have it, once I decended below the freezing level(about 3000 MSL),the ice cleared off the airframe (at about 900 AGL) and I got my SE performance back and continued to the airport. I did make d#mn sure that during the time I had the load of ice that I didn't come anywhere close to VMC and took the loss of altitude rather that losing control. That is what I think some of the pilots forget and end up in bad shape. A controlled landing in a field is always better than a VMC roll and a back flop into a field!!!

 

[sky37d]

In theory it sounds good. The only problem is that the safety statistics for all of the various Skymaster varients don't bare it out - they're as bad as for any other light twin.

'Sled

Most of that is stupid pilot tricks, like taking off with only 1 engine from a 3000 ft runway, that ends in the ocean (he got the darwin award!!). Or running out of gas.
Unfortunately many have been CFIT.

I have had to feather the rear prop in flight, and land single engine. Twice. It was a non-event, just a big slow single engine airplane.