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Some Random Questions  
User currently offlineDg_pilot From United States of America, joined Sep 1999, 856 posts, RR: 2
Posted (11 years 5 months 2 weeks ago) and read 2458 times:

Hey guys,

The other day I was in class day-dreaming about flying and came up with a few questions I cannot easily come up with answers for. Maybe you guys could help me (and prob. some others) out?

How does a remote-communications outlet (RCO) work? Does the RCO itself just pick up the local signal and then amplify it enough for the distant receiver to pick it up?

When doing the runup/taxi in planes equipped with constant-speed props, why do we use RPM settings rather then manifold pressure settings on the ground?? Is it because the engine is not producing enough power for an accurate manifold reading? The more I fly constant speed props, the more I realize I do not have a complete, thorough understanding of manifold pressure. I do not think a lot of people do.

On most planes there is a battery drainage or exhaust. What gas is produced by your typical GA battery?

Scenario: Taking off from a 3,000 (or so) foot runway, your left engine fails and your gear is up. Requiring some 5,500 feet (accelerate-go) it appears as if you cannot climb over that 50 foot tree at the end. So now you are gear up, unsure whether you can climb over the trees, and unsure you have enough runway and time to set it back down. Other then maintaining control of the twin, what now?

The place I fly at now specifies that unless you are above 3,000 AGL, you should not attempt to troubleshoot the failed engine on your twin. Is this a pretty universal thumbrule? Just curious.

If anyone else has some random questions, by all means, add them on here. I believe that in aviation we should try to figure out as much as we can. You never know when it might come in handy.

24 replies: All unread, jump to last
 
User currently offlineLY744 From Canada, joined Feb 2001, 5536 posts, RR: 10
Reply 1, posted (11 years 5 months 1 week 6 days 22 hours ago) and read 2390 times:

I'll take advantage of that offer. Inspired by the RCO question: My local airport's tower is closed at night, and there is a published RCO and ATF frequency (different frequencies), which one would a pilot tune into if he/she is operating when the airport is uncontrolled?

LY744.



Pacifism only works if EVERYBODY practices it
User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 2, posted (11 years 5 months 1 week 6 days 22 hours ago) and read 2402 times:

I’ll take a stab at your questions…

Q1. How does a remote-communications outlet (RCO) work? Does the RCO itself just pick up the local signal and then amplify it enough for the distant receiver to pick it up?
A1. RCOs are simply remote transmitter/receiver sites connected to the ATC facility via land (telephone) lines.

Q2. When doing the runup/taxi in planes equipped with constant-speed props, why do we use RPM settings rather then manifold pressure settings on the ground? Is it because the engine is not producing enough power for an accurate manifold reading? The more I fly constant speed props, the more I realize I do not have a complete, thorough understanding of manifold pressure. I do not think a lot of people do.
A2. At low RPM settings, the prop govenor will keep the propeller in “fine pitch” and the propeller will essentially act as if it was fixed pitch. The manifold pressure gauge is basically a barometer; when the airplane is sitting static with the engine shutdown, the manifold pressure gauge will indicate the local barometric pressure. Here’s a good website to help explain the workings of the manifold pressure gauge: http://www.avweb.com/articles/pelperch/pelp0015.html and another for the workings of a constant speed propeller: http://www.avweb.com/articles/pelperch/pelp0016.html

Q3. On most planes there is a battery drainage or exhaust. What gas is produced by your typical GA battery?
A3. It’s hydrogen gas.

Q4. Scenario: Taking off from a 3,000 (or so) foot runway, your left engine fails and your gear is up. Requiring some 5,500 feet (accelerate-go) it appears as if you cannot climb over that 50 foot tree at the end. So now you are gear up, unsure whether you can climb over the trees, and unsure you have enough runway and time to set it back down. Other then maintaining control of the twin, what now?
A4. I would have to ask the question: “What are you doing at an airport like that in a light twin? Trying out for the Darwin Awards? Forget the “accelerate-go” charts (they’re not available for all light twin aircraft); besides, 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.

Q5. The place I fly at now specifies that unless you are above 3,000 AGL, you should not attempt to troubleshoot the failed engine on your twin. Is this a pretty universal thumbrule? Just curious.
A5. There are a couple schools of though when it comes to in-flight troubleshooting – one school believes that’s it’s OK, the other school believes that it’s best to get the airplane safely on the ground and let the mechanics do what they’re best at doing. I’m a proponent of the latter – get the airplane safely on the ground. It won’t hurt to take down some observations to help the mechanics do their job, but too many aircraft have been lost because the pilot(s) forgot that his first obligation is to fly the airplane, not troubleshoot a maintenance issue. That being said, if I’m flying at 2000’ agl in one of your place’s airplanes and I loose an engine because I run out of gas in one of the tanks, am I not going to “troubleshoot” the failure and switch tanks? Of course I am. Personally, I think that it’s a pretty dumb rule – I’ve seen too many “problems” that can be easily fixed by just a little bit of troubleshooting.

Q6. My local airport's tower is closed at night, and there is a published RCO and ATF frequency (different frequencies), which one would a pilot tune into if he/she is operating when the airport is uncontrolled?
A6. Look for the "CTAF" (Common Traffic Advisory Frequency) in front of one of the frequencies - that's the one you would use. Typically, it's the tower frequency.

Jetguy


User currently offlineLY744 From Canada, joined Feb 2001, 5536 posts, RR: 10
Reply 3, posted (11 years 5 months 1 week 6 days 21 hours ago) and read 2377 times:

"Look for the "CTAF" (Common Traffic Advisory Frequency) in front of one of the frequencies - that's the one you would use. Typically, it's the tower frequency."

That would be the ATF, and it is indeed the same frequency as the tower. An ILS chart for the airport also contains the following statement: "When tower is closed call LONDON RADIO on 126.7 for clearance", 126.7 is the RCO frequency. What does that mean? Also, in general, why would both an ATF and RCO be needed at the same airport? Don't they essentially have the same function?

LY744.



Pacifism only works if EVERYBODY practices it
User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 4, posted (11 years 5 months 1 week 6 days 21 hours ago) and read 2376 times:

Oops, I didn't realize that you were in Canada - eh? (Sorry  Innocent )

The ATF (CTAF) is used to get you in and out of the airport area - to talk to and listen for other aircraft operating in the vicinity of the airport. The RCO is to talk to London Radio to pickup or cancel IFR flight plans when the tower is closed. When the tower is open, they handle that chore.

Jetguy


User currently offlineDg_pilot From United States of America, joined Sep 1999, 856 posts, RR: 2
Reply 5, posted (11 years 5 months 1 week 6 days 20 hours ago) and read 2359 times:

Jetguy,

I understand your answer on my engine-out scenario question. The thing I do not know is what is considered normal for twins as far as runways. I am brand new to them so I know about nothing as far as what people routinely land their light twins on.

So the accelerate-go (and stop?) charts should not be relied on at all?

Thanks!


User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 6, posted (11 years 5 months 1 week 6 days 18 hours ago) and read 2356 times:

Like a lot of things in aviation, there are many factors to consider in answering your question. What type of twin are we talking about? Is it turbocharged? What's the airport elevation? The OAT? What are the runway obstacles? Is it light, or are you at MGTOW? etc...

That's why it's really the insurance companies that control who gets to fly the larger, more complex aircraft - not the FAA or Transport Canada. Although practically anyone with enough money in their wallet to pay for the training can get the rating, it's only those with the necessay 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. ThirtyEcho said it as well as anyone when he wrote: "...just make sure that you get lots of instrument dual in it before you start flying IFR or night flying. The temptation is to regard a twin as an all-weather airliner and to get yourself in trouble by tackling situations before you have enough experience to handle them. Pay lots of attention to weight and balance, too."

I don't mean to sound paranoid, but flying is nothing more that an exercise in risk management. You take acceptable risks and eliminate or at least minimize unacceptable ones. It's not that 300 hour private or commercial pilots can't handle the "control manipulation part" of flying, they certainly can. Many of them can fly circles around us when it comes to specific manuvers that they might be performing on a daily basis and we might not have done for months or years. The issue is one of depth, not breath of knowledge. Pilots in this position (and every one of us old farts have been there) have a broad range of knowledge, it just doesn't run very deep. That's what experience does - deepens your knowledge and understanding.

I only earn my money on those very infrequent days that I have to tell my boss "no". When the weather is good and when the equipment is operating correctly it doesn't take much of a pilot to do my job. It's when we have to deal with "difficult" weather, "belligerant" equipment, and/or "challenging" airports that I earn my money. In other words, I get paid to say "no". However, they expect me to have the skill and experience to only say "no" when it is the only safe option. Inexperienced pilots get into trouble when they say "no" and it wasn't necessary or when they don't say "no" when it was.

You'll notice that I've been dancing all around your question - that's because there is really no absolute answer. Do you avoid using the charts? Absolutely not! However, you need to understand what they are telling you and, just as important, what they don't tell you. When you're sitting at the end of that 3000' runway with the 50' trees at the far end you've got to assume that on this particular takeoff the engine will decide to "pack it in". Some twins might be able to handle it under certain conditions, but what if you've got 4 passengers at a mountain airport on a 25C day in ThirtyEcho's 160 hp Apache? Five lives are at stake. Would a competent pilot even consider a takeoff under those conditions? Light twins are perhaps the most demanding airplane you'll ever fly. They're far more demanding to fly than most turbine-powered aircraft. You can't get complacent - the graveyards are filled with thousands of complacent pilots and their passengers.

Oops, I've got to get off of that soapbox before someone knocks me off it.



User currently offlineB747skipper From , joined Dec 1969, posts, RR:
Reply 7, posted (11 years 5 months 1 week 6 days 17 hours ago) and read 2326 times:

Light twin engine aircraft operation philosophy...
xxx
I have never operated nor flown light twin aircraft, but read a lot of material about such type of aircraft, and talk to many pilots who fly them, some with a flot of experience, some with almost no experience...
xxx
A few years ago, while with PanAm, I often heard airplanes being "ferried" on delivery flights from USA to Europe... some light twins, some single engine... often was to relay a position report on VHF, if their HF was not working well. Also met some of these pilots in airport hotels, Gander, Shannon... etc...
xxx
One I remember well, that was his normal flying activity... among the many questions I asked him, was about flying a single engine aircraft, versus a twin engine aircraft - his answers surprised me...
xxx
He told me that there was more danger (more likelyhood) of ditching a light twin than a light single in the ocean... two engines = double the chances of getting engine problems (compared to a single engine aircraft), the second engine will not bring the aircraft back (or permit the aircraft to continue) to a safe airfield... most of such airplanes are heavily loaded with extra tanks and, on the remaining engine, the best is to hope that there is a ship nearby to assist them for the ditching...
xxx
I do not know where the classification of a "safe twin" and unsafe (underpower) twin is... I do not know what power would be sufficient to permit a given type of aircraft to fly with one engine out... weight, and, pilot proficiency are factors to be considered as well...
xxx
As many of you know, I fly a little "L-21 Super Cub" for fun, teaching my son, and I have fairly good proficiency with that aircraft. However, when will come time for him to learn to handle a twin engine aircraft, I will seek a knowledgeable twin engine instructor for his training... Many acquaintances at the aeroclub have asked me to teach them to fly light twins, to which my answer is "no, I do not have sufficient experience with these..." then, they say to me - "hell, dont you have zillion hours in multiengines...?" - yes, I do - in the kind of airplanes that still climb with an engine out...
xxx
My undeducated pilot advice to any of you flying a light twin, on takeoff, and having an engine failure with 50, 100, 200 feet altitude = LAND STRAIGHT AHEAD, DO NOT ATTEMPT ANY TURNS - use the remaining engine to assist your landing to a field without obstacles...
xxx
FLY SAFE -
(s) Skipper -  Wink/being sarcastic who has 20,000+ hours multiengine time...


User currently offlineSkyguy11 From , joined Dec 1969, posts, RR:
Reply 8, posted (11 years 5 months 1 week 6 days 17 hours ago) and read 2313 times:

Your twin question leaves too many unknowns to be answered. However in that situation you would be forced to make a quick decision based on availble facts, if clearing the tree is doubtful, drop the gear and make for the ground. At least if you hit something then you'll have slowed down and you won't have to endure the subsequent fall from the sky, leaving the survival odds in your favor.

If clearing the tree looks likely then do just that, thank your lucky stars, and never make the same mistake twice.

I doubt any amount of debating will change anything if you do find yourself in this situation; you are bound to decide based on what you see; I guarentee you won't think 'hmmm... what would the guys from airliners.net do....'.


User currently offlineDg_pilot From United States of America, joined Sep 1999, 856 posts, RR: 2
Reply 9, posted (11 years 5 months 1 week 6 days 8 hours ago) and read 2258 times:

Discussions like these are what I enjoy on this board. Ya know what I mean? I will try to type more later.

User currently offlineLY744 From Canada, joined Feb 2001, 5536 posts, RR: 10
Reply 10, posted (11 years 5 months 1 week 6 days 1 hour ago) and read 2224 times:

Thanks Jetguy!  Smile

LY744.



Pacifism only works if EVERYBODY practices it
User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 11, posted (11 years 5 months 1 week 5 days 18 hours ago) and read 2197 times:

Skipper had some good observations, but there were a couple of points that I'd like to expand upon.

He made the comment "...He told me that there was more danger (more likelyhood) of ditching a light twin than a light single in the ocean... two engines = double the chances of getting engine problems (compared to a single engine aircraft), the second engine will not bring the aircraft back (or permit the aircraft to continue) to a safe airfield... most of such airplanes are heavily loaded with extra tanks and, on the remaining engine, the best is to hope that there is a ship nearby to assist them for the ditching..."

That is absolutely correct, but it needs to be emphasized, that he is referring to aircraft that are being flown on special permits and are being operated grossly overweight - not typical at all of the normal operating weights.

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 all 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.

I’ve only flown one light twin that had single-engine performance worth mentioning (and I’ve got significant amounts of time in nearly every make and model out there) and that was the Baron 56TC. It was almost "jet-like". The airplane had a Beech B55 airframe and 380 hp Lycoming engines – the same ones that were used on the Beech Duke. The basic airframe was originally certified with 180 hp engines as the Beech Travel Air. The 56TC had 20 more than twice the original horsepower – on each wing! That airplane is the exception rather than the rule.

My point remains, in the scenario described by DG Pilot, would a prudent pilot attempt a takeoff in a light twin with a 3000’ runway and a 50’ obstacle at the far end. Personally, all things being considered, I doubt it.

Jetguy


User currently offlineB747skipper From , joined Dec 1969, posts, RR:
Reply 12, posted (11 years 5 months 1 week 5 days 18 hours ago) and read 2179 times:

Dear Jetguy - and friends -
My IQ of part 23 airplanes is somewhat limited - I am chicken when it comes to some light twins, i.e. Piper Apache with 2 x 160 hp engines... I understand that Twin Comanches, same engines do much better performance...
The only "high performance" single aircraft I fly (rarely) is a Siai-Marchetti SF-260, scare myself (attempting acrobatics) occasionally, but I love it... If I was a rich dentist, like the owner of that aircraft, I would definitely get one... now he wants to buy a light twin... status symbol I assume...
 Wink/being sarcastic
(s) Skipper


User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 13, posted (11 years 5 months 1 week 5 days 2 hours ago) and read 2104 times:

Skipper...
I happen to agree with you 110% - there are a lot of light twins out there that really scare me. Out here in the mountains, I won't even ride in a normally aspirated twin. Like you said, there's twice the chance of an engine failure; like I said, you lose 90%+ of your climb capability; like you said, the remaining engine will just have enough "oomph" to take you directly to the scene of the accident; and finally, like I said, I just don't care to put my self in a position where my sweet little fanny has to absorb a lot of energy in an off field landing. As far as I'm concerned, there's nothing wrong with the majority of the turbocharged twins - as long as they're flown conservatively. In fact, if I ever can afford it, I'd love to own a Pressurized Aerostar...

http://www.aerostaraircraft.com/N13PS.html

Jetguy

Now you understand why my motto is: "Propellers are for boats!"  Big thumbs up



User currently offlineSkyguy11 From , joined Dec 1969, posts, RR:
Reply 14, posted (11 years 5 months 1 week 5 days 2 hours ago) and read 2092 times:

Now, both of you guys are used to flying the 'big iron'; the stuff where everything has a backup system, and just about anything that goes wrong is non critical due to the backup just waiting for the chance to kick in. What about us folks who only have the choice between a single piston and a twin piston?

Are you saying you'd rather fly a single than a twin? Now I see where you guys are coming from and on the whole I agree, but I think that like all aspects of flying, if you are smart about it, you can get the added benefit of the extra engine and extract even more utility from your flying with an increased margin of safety.

Yes, the more you have the more can fail, but that extra engine could very well save your life. Let's say you can't even maintain altitude. Your 'glide' ratio in a twin with a failed engine will beat the pants off an single with a failed engine anyday, making an off or on airport forced landing a much safer ordeal due to the simple fact that you will have more places to chose from should that engine quit.


User currently offlineB747skipper From , joined Dec 1969, posts, RR:
Reply 15, posted (11 years 5 months 1 week 5 days ago) and read 2084 times:

Dear Skyguy11 -
xxx
You probably think we are spoiled brats... it is just that I am concerned when made aware of some ideas of the pilots who fly light aircraft... some the ideas are merely enthusiasm - but some is gross misinformation...
xxx
I am member of my airline's aeroclub, where many non-pilot employees learn to fly aircraft, mechanics, flight attendants, reservation or traffic agents, and many line pilots offer their free service as pilot instructor. My own little plane, a Piper L-21 is one of these planes. I teach my son, age 13, to fly at the club.
xxx
I have 2 worries with low experience pilots - their misunderstanding of "the instrument rating", and "multiengine aircraft"... For them, an instrument rating often means that they "can fly with any bad weather - low visibilities", this regardless of their aircraft... Same for a light twin, for them, the "left engine quits" but they will be able to continue to their destination...
xxx
I do not teach to fly light twins, I merely volunteer as a taildragger instructor with my plane, and I teach IFR flying (when CAVOK...) and at the clubhouse, I am willing to lecture basic navigation, meteorology, or radio communications English - provided that my mug is kept full of beer... until midnight - if my wife gives me permission...
xxx
My dentist, a good friend, has a SF-260 high performance aircraft. Last year he asked me to teach him IFR flying with that airplane, nice equipment. We flew a long trip together to Santiago in Chile, crossing the Andes, with the mountain passes at 14,000 MSL - this without oxygen equipment...
xxx
Now he wants to buy a twin engine aircraft, since he goes to Santiago very frequently - he is convinced that such aircraft will be safer to cross the Andes. The little hills around there are at... 22,000 feet (Aconcagua)... This is what I am trying to educate pilots about...
xxx
Teaching IFR is rather easy - it is procedures for ATC purpose in traffic, much like teaching an individual to drive on an expressway, when their experience in driving is on two-lane country roads only... But teaching twin engine aircraft performance capability to PPL pilots is at times, "beyond me"...
xxx
Flying safely is (1) proficiency, and (2) being conservative... people who fly in airlines or corporate aircraft most often are both, yet occasionally there will be accidents... sometimes their airplane equipment fails them, sometimes they make a pilot error, despite their proficiency and good judgment... Dentistry and ability to buy an expensive twin engine aircraft is one thing, but you cannot buy proficiency.
xxx
He is such a good dentist, we get free dental care, my wife, my son and my daughter - do not want to kill him yet...
Fly safe, all of you - Happy contrails  Smile
(s) Skipper



User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 16, posted (11 years 5 months 1 week 4 days 21 hours ago) and read 2069 times:

Skyguy11,
You’re absolutely correct with your comment, “Now I see where you guys are coming from and on the whole I agree, but I think that like all aspects of flying, if you are smart about it, you can get the added benefit of the extra engine and extract even more utility from your flying with an increased margin of safety.” That is very true; but, here’s the catch…

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).

Would I rather fly in a single? Well yes and no. (Remember, my personal dream plane is a P-Aerostar) It depends upon what I’m trying to do. One of the big lessons that all pilots need to learn if they want to grow old is what is safe isn't always legal and what is legal isn't always safe. A pilot has to simultaneously operate within 3 specific spheres to maintain an acceptable level of safety:

1. The pilot’s individual limitations. A freshly soloed student pilot will have different personal limitations than a 500-hour private pilot, who will have different personal limitations than a 20,000-hour airline captain.

2. The aircraft’s limitations. There will always be aircraft that are more suited for a particular mission than another. A Super Cub might be just the ticket for flying off of a sand bar in Alaska, but you wouldn’t want to try shooting an ILS to minimums in icing conditions in one. A Lear is one fine airplane, but it isn’t the machine you want to be operating if your runway is only 3,000’ long. All aircraft have limitations whether they are a Super Cub or a B747. A Cessna 172 is probably one of the finest general aviation aircraft ever built and it has one of the best safety records. Can it be misused? Of course – fill it with fuel, put four people in it, and try taking off from an airport in Colorado during the middle of summer. You’ll probably make the headlines in the local papers.

3. The legal limitations imposed by the FARs.

Where pilots get into trouble is when they attempt to operate outside of the area where all three spheres intersect. The accident record is full of reports where highly experienced airline or corporate pilots “bought the farm” trying to operate in conditions that the aircraft wasn’t suitably equipped to handle. (For example, trying to shoot an ILS to minimums in icing conditions in a Super Cub.) The same thing goes for “VFR only" private pilots continuing into IFR conditions in suitably equipped aircraft. The same would be true of an experienced pilot trying to operate a light twin under conditions that would leave him/her “hanging” if an engine quit.

You’ve heard the old saying…

“There are old pilots and there are bold pilots, but there are no old, bold pilots.”

DG Pilot’s light twin scenario is exactly what the person who came up with this saying was referring to. You can ignore the dangers, and place your trust in the laws of probability. (After all, they say that nowadays, an engine failure is a “once in a career” occurrence – yeah, right!) But remember, if you choose this path, the danger doesn’t go away, it merely lies in wait.

Hey, we’ve all been there. In the exuberance of youth and with the desire and drive to build up our flying credentials many of us are willing to do just about anything to get our hands on an airplane. There was a time when I wouldn't have given much thought to operating properly equipped and maintained single-engine or multiengine light airplane almost anywhere, anytime day or night. That however, was a long time ago. I now have a much better understanding of just what can go wrong and realize that there are just some operations that are better off not being attempted.

As long as I’m quoting interesting old aviation sayings, here’s another one that I think pertains to the situation…

“A superior pilot is one who uses his superior judgment to avoid situations requiring the use of his superior skills.”

Your final comment, “Yes, the more you have the more can fail, but that extra engine could very well save your life. Let's say you can't even maintain altitude. Your 'glide' ratio in a twin with a failed engine will beat the pants off an single with a failed engine any day, making an off or on airport forced landing a much safer ordeal due to the simple fact that you will have more places to chose from should that engine quit.”

That statement sounds reasonable. (I’m sure that many aircraft salesmen have used it as part of their multiengine aircraft sales pitch.) But, again, an assumption is made that the statistics don’t necessarily support. Believe me, there is a big difference between maintaining control during a carefully choreographed training exercise, when you know that you’re going to be losing an engine and having the loss of an engine catch you totally off guard and completely unexpected. Like I said in one of my previous posts, light twins are perhaps the most demanding airplanes you'll ever fly. They're far more demanding to fly than most turbine-powered aircraft. I like to compare them to having a pet Doberman. They can make great pets - they'll lick your hand and face, but if you do anything "stupid" around them they can turn on you. These airplanes are no different.

All aircraft are “flying compromises”. In this thread, we’ve been talking about the wisdom of trying to takeoff in a light twin from a 3000’ runway with a 50’ obstacle at the far end. To me, that is “Faith-Based Aviation” – you’re betting your life (and the lives of your passengers) that an engine won’t quit during takeoff and for a certain period afterward. Personally, I believe that is an unacceptable risk.

Jetguy


User currently offlineSkyguy11 From , joined Dec 1969, posts, RR:
Reply 17, posted (11 years 5 months 1 week 4 days 20 hours ago) and read 2034 times:

Jetguy and B747skipper thanks for the quick replies. I'm really just playing devil's advocate; all I fly for the time being are single engine trainers. Jetguy, you did say one thing that I had to think about for a bit (I don't know how to do the fancy bold font either...):

---------------------
All aircraft are flying compromises. In this thread, we've been talking about the wisdom of trying to takeoff in a light twin from a 3000' runway with a 50' obstacle at the far end. To me, that is 'Faith-Based Aviation' - you're betting your life (and the lives of your passengers) that an engine won't quit during takeoff and for a certain period afterward. Personally, I believe that is an unacceptable risk.
---------------------

Once again, I completely see where you're coming from. However, it seems to me that when you fly a single, you're betting your life and the lives of your passengers that your only engine won't quit during takeoff and for a certain period afterward every time you fly. Now, hopefully you will quickly find a place to put it down, or even better, you've already searched the departure end of the runway during your arrival for spots and you already have a place in mind.

According to your twin logic, how can this be an acceptable level of risk? What other options does one have other than not to fly at all? I suppose you could avoid all airports with less than 5000' of runway and anything other than flat terrain, but then you're losing a lot of practicality and many people don't even have access to this kind of an airport. How do you justify single and even multi engine piston flying?

To me, this is a risk that I must accept (and I do) if I am to reasonably fly GA aircraft. I can't control engine failures but I can control my actions after the fact. With a little luck, I'll make it out OK. What happen's if luck is not on my side? That's the risk I accept.


User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 18, posted (11 years 5 months 1 week 4 days 18 hours ago) and read 2039 times:

Skyguy,
You raise a good point and have a valid question. It’s too bad that we can’t have this conversation face-to-face, it would be much easier. It’s all too easy to be ambiguous when you’re trying to express your personal opinions in writing. I’m not advocating that flying GA aircraft is unacceptably dangerous; to the contrary, it’s amazingly safe. The points that I made concerning light twin operation pertained primarily to the operation off a short runway with an obstacle at one end. Take away the obstacle and my opinion on the operation changes. Also, remember that these are simply my personal opinions. Other experienced pilots may have differing opinions that are equally valid.

You made the comment, “…it seems to me that when you fly a single, you're betting your life and the lives of your passengers that your only engine won't quit during takeoff and for a certain period afterward every time you fly. Now, hopefully you will quickly find a place to put it down, or even better, you've already searched the departure end of the runway during your arrival for spots and you already have a place in mind.” That is correct. It is a risk, although a slight one, and one that is easily managed.

Remember what you were taught as a student pilot? If you ever lose an engine right after takeoff, NEVER attempt a turn back towards the airport unless you have sufficient altitude. Basically, your only option is to land straight ahead or at the most slight turns in either direction. In the event of an engine failure, your chances of walking away from the aircraft after it has come to rest is pretty good provided you remained the pilot throughout the event and did not allow yourself to become merely another passenger.

Remember, the Feds have tried to stack the deck in your favor – even the big Pilatus PC-12 has a stall speed no higher than any other light single-engine airplane. With those reduced stall speeds comes a BIG safety margin that isn’t there with many light twins. Remember, 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 can 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. Historically, not a lot of people walk away from off field landings in twins. That's if you even make it to the field. Unfortunately, many light twin accidents start out as an engine failure which is compounded by the loss of control when the pilot allows the airplane to decelerate below Vmc. Once directional control is lost, the airplane turns itself into a Frisbee and everything else becomes academic.

As far as light twins go, it all depends on the particular operating conditions. Many normally aspirated twins have a single-engine service ceiling of 5000’ or less (Some a lot less.) What’s going to happen when one of those aircraft attempts a takeoff at an airport, say in Utah or Colorado (4,000’+ MSL) on a hot summer day when the density altitude is in the neighborhood of say 8500’? If you lose an engine under those conditions, it doesn’t take a rocket scientist to figure out what’s going to happen next. Let’s say you’re in a Baron Be-58. Your stall speed will be significantly higher than 61 knots and your fanny is going to have to – at some point – absorb a lot of energy. It would make your day so much nicer if you didn't have to put it down in that field. This is where the turbocharged twins make a lot of sense – out west where there are many high elevation airports. Many of them have single-engine service ceilings in the mid-teens. This doesn't mean that you can expect them to climb with very much enthusiasm on one engine; but thay can usually manage some climb and maintain an altitude once they've reached it. (This is a good thing in the event that you are flying IFR in the mountains - some of those MEAs can be pretty "tall".)

Normally aspirated twins are just fine on both coasts and in the Midwest. I’ve given a lot of dual in the mountain west in normally aspirated twins. They’re fine in the training role, in fact they tend to make new multi pilots real believers when they experience, first hand, their anemic performance. However, a normally aspirated light twin for a “day to day” working airplane out West, not for this kid thank you.

Bottom line is it’s not the number of engines that you have. It’s the skill, experience level and, most important, the good judgement of the pilot that ultimately determines the safety of any given operation. A good pilot will evaluate each flight and say “no” when it’s the best option or put in place whatever conditions necessary. Flight safety is achieved when you have a well-trained, competent pilot, flying good, well-maintained equipment within the envelope of its operating parameters.

Jetguy


User currently offlineTT737FO From United States of America, joined Jun 2001, 472 posts, RR: 9
Reply 19, posted (11 years 5 months 1 week 3 days 19 hours ago) and read 1946 times:

Oh Gawd! There is a saying that airline pilots make the worst general aviation/private pilots...and Skipper posted another beauty:

"We flew a long trip together to Santiago in Chile, crossing the Andes,
with the mountain passes at 14,000 MSL - this without oxygen equipment...


For those of you out there taking this guy seriously... please don't try this!! The FAR states that at the minimum flight crews must be provided with and use supplemental oxygen after 30 minutes of exposure to cabin pressure altitudes between 12,500 and 14,000 ft, and immediately upon exposure to cabin pressure above 14,000 ft. Really, you ought to be using supplemental o2 above 10,000 ft at any time. There is a good reason for it.

Here is another gem:

"Teaching IFR is rather easy - it is procedures for ATC purpose in traffic, much like teaching an individual to drive on an expressway, when their experience in driving is on two-lane country roads only."

Ok, sure. Lets forget about hooding the student up, teaching the 5 ts, teaching the scan, teaching the student to keep the head still so as not to throw off equilibrium. Teaching instrument flying may be a little different down south, but most pilots consider it to be a real challenge.

Now onto another point about the problem itself:

If this aircraft is in serious trouble (and it is) then there is a good chance that it will drop below Vmc in a real hurry. Here is an ME wrinkle that goes counter what we have been taught: When below Vmc, THROTTLE BACK! Why? Zero power is certainly no good, but in this case the power will be equal--therefore no catostrophic yaw will be produced. Below Vmc, the rudder will have no effect on offsetting the yaw.


User currently offlineB747skipper From , joined Dec 1969, posts, RR:
Reply 20, posted (11 years 5 months 1 week 3 days 17 hours ago) and read 1913 times:

Dear TT737FO -
First of all thank you for expressing your respectful and kind opinions of myself - in no uncertain words -
xxx
As to my trip last year to Santiago and flying the Andes, shall mention to you that I was merely a passenger in a privately operated aircraft flown by a friend - to which I had recommended to rent oxygen equipment, and the said equipment we attempted to rent in Mendoza was not available when we landed there to refuel the aircraft. So there was no fault since I am merely a passenger. My friend is a licensed PPL and owns that aircraft, which was not operated for hire... He operated against my recommendation.
xxx
The FAR (shall we specify United States you mentioned), is not the rule of the air law of Argentina nor Chile, FAR regulations are only in force North of the Rio Grande, and not applicable to Argentina registered aircraft flown outside of US airspace.
xxx
I do not appreciate your disdain of my effort in educating pilots to the best of my advice - it seems that my airline employer has a different opinion of the manner I take my responsibilities as flight training manager.
xxx
Happy contrails - stay in your airspace - I hardly ever go to ORD anyways...
(s) Skipper


User currently offlineDg_pilot From United States of America, joined Sep 1999, 856 posts, RR: 2
Reply 21, posted (11 years 5 months 1 week 3 days 7 hours ago) and read 1840 times:

For the record, my scenario about the 3000 foot runway with the 50 foot obstacle at the end is one I have seen more then once. I am still working on my multi, but throughout the years, I have seen people frequently take light twins into airports with less then 4 to 5 thousand feet of runway. Were the typical departure ends favorable to forced landings? Rarely. Either they had trees, utility lines, antennas, or were just plain rough or unlevel.

As a pilot that is learning to fly multi-engine aircraft, there is now a whole new set of concepts I must consider before I make any ME flight. Flying primarily singles before, there were fewer decisions available to be made during takeoff and climbout. In other words, if the engine quit, you're going down no matter what. Lower the nose, and pick the most practical place. The end. Now, with the extra engine, do I climb out? Can I even turn slightly? Do I salvage a landing in that field? What about the runway? What about the gear? Etc... Careful airport and runway selections are even more critical to every flight.

So how does that relate to the 3000 foot runway scenario? Like I said, I have seen many twins go into shorter strips such as that, and as a ME pilot in training, occasionally see discrepancies between what is taught and what I have seen people do over and over. So is what I have been taught just a little too on the impractical side(?), or are the pilots I see that take their twins out of small runways actually being inconsiderate of the inherit dangers? You see, there are so many questions involved here. Especially for a new ME guy. So what DO I know? I know that I don't know enough. I am beginning to realize the dangers and every time I hear about a scenario or accident, I ask myself, "Well, what would you do?"

Hopefully I don't sound like a idiot.


User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 22, posted (11 years 5 months 1 week 2 days 18 hours ago) and read 1853 times:

DG…
No, you don’t sound like an idiot. You’ve made got some very good observations and you have raised some legitimate questions. Let me state, up front, that there are no easy or simple answers to the questions that you have either raised or inferred. 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.

As I mentioned in one of my previous postings - the bigger the airplane, the easier they are to fly. That’s the truth. The most demanding airplanes that most people will ever fly are light, piston-powered twins. They are very capable machines; but at the same time, it’s all too easy to get in way over your head in them. In Part 25 transport category aircraft, you not only have all of the various systems and “backups”, but you also have built in performance guarantees. Part 23 light twins have none of the above, in fact, they have two engines because the need two engines and under certain favorable conditions, they can maintain controlled flight on one engine IF THE PILOT DOES EVERYTHING CORRECTLY. Remember, in a light twin if you lose an engine you lose 50% of your power and 90%+ of your climb capability. In a very real way, and the accident statistics bear me out on this, twins are more dangerous than singles and should be flown conservatively.

I think that it’s probably my statement about the need to fly light twins conservatively that’s causing your concern. What I’m advocating isn’t really limiting their utility. (No more than saying that you shouldn’t fly single engine aircraft over weight is limiting, but there will always be those who are willing to ignore the W&B envelope and fill all of the seats, load the baggage, top off the tanks and go. To me, this is exactly the same principle.) We had a similar discussion a while back at FlightSafety. We occasionally have to deal with the same mentality in the corporate world – “The engine isn’t going to quit, why shouldn’t we load our passengers with enough fuel to make it to ‘where ever’ without having to make a fuel stop…” or (this is my personal favorite) “They build in a big enough safety margin that we can ignore the charts…”

So what if a lot of people operate their aircraft in a way that that leaves them “exposed”? Lets assume that they have done it for hundreds 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.

As I said in one of my earlier posts, I believe that flying is essentially an exercise in “risk management” – you accept reasonable risks and try to eliminate or, at least, minimize the rest. Can you make flying totally risk free? Of course not, no more than you can make any other activity that we do risk free. However, if you go about it properly, flying is as about as benign an activity as you can possibly do. I have a framed photo of an old biplane hung up in the limbs of a tree. (You’ve probably seen the one I’m talking about, they’re in just about every pilot shop in the country.) The photo’s caption reads, “Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect.” I agree with that statement.

Now back to your questions…

Q1. So is what I have been taught just a little too on the impractical side(?), or are the pilots I see that take their twins out of small runways actually being inconsiderate of the inherit dangers?
A1. Getting a ME rating is no different than getting a pilot’s license or an instrument rating. A license or a rating is nothing more than a license to learn. There is perhaps nothing more dangerous than a “green” instrument pilot out in the weather. Passing a written and taking a checkride no more makes you an instrument pilot than buying a piano would make you a concert pianist. We all start out “green”, but as we gain more experience, hopefully, we become “seasoned”. That’s what experience does for you, you don’t manipulate the controls “better”, you just fly “smarter”. Us old farts can’t let our guard down either. Remember in your initial flight training days how they talked about safety plateaus? Accidents seem to cluster at certain distinct points – 100 hours, 500 hours, 1000 hours, 3000 hours, 10000 hours, and 20000 (if I remember correctly). This occurs not only with total time, but also with “time in type”. There is a real tendency to get too comfortable and let your guard down. A 10000-hour pilot with 3000 hours in type needs to be careful that he doesn’t get complacent or he too, will get bit. Unfortunately, over the years, I have known many good pilots who have died in aircraft accidents. When it happens, it is a VERY sobering experience. All too often, as you look back on the events surrounding the accident it becomes very apparent that, in many cases, it was very avoidable. It’s all too easy to let bad operating practices creep into our day-to-day flying. Like the guy said when St. Peter met him at the Pearly Gates, “It never killed me before!”

Q2. So what DO I know? I know that I don't know enough. I am beginning to realize the dangers and every time I hear about a scenario or accident, I ask myself, "Well, what would you do?"
A1. No one is born with 10000-hours in their logbook. We all have to gain our experience an hour at a time. What I would recommend that you do is to establish, in advance, your personal minimums and limitations. Then CAREFULLY go about expanding them a little here and a little there. Also, be sure to come up with a personal plan for recurrent training. It will take a while but you’ll get to the point that you’re comfortable and competent (not complacent) with flying complex aircraft in most any situation.

Jetguy


User currently offlineDg_pilot From United States of America, joined Sep 1999, 856 posts, RR: 2
Reply 23, posted (11 years 5 months 1 week 2 days 17 hours ago) and read 1790 times:

Jetguy,

"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."

I like how you put that. Such thinking does in fact place your destiny at the hands of inevitability. I remember hearing a NetJet pilot say once how he and his company refuses to fly into Aspen with particular jets because if the once-in-a-million engine failure occurred while they are heavily loaded, they would be unable to climb clear of the rising terrain. The passengers would usually be angry as to why other similar jets were taking off without any restrictions but they couldn't. After telling the pax that their personal safety was of such great importance to him that it simply wasn't worth the chance, they would usually calm down and see the other side of things.

"What I would recommend that you do is to establish, in advance, your personal minimums and limitations. Then CAREFULLY go about expanding them a little here and a little there."

I think this is always a good idea. The hard part is figuring out exactly where to start. That is one thing the training is good for I believe; to figure out the aircraft and its characteristics, and just as importantly, to figure out my personal capabilities most coherent with safety in the new plane.

Thanks again...


User currently offlineMd11nut From , joined Dec 1969, posts, RR:
Reply 24, posted (11 years 5 months 1 week 4 hours ago) and read 1684 times:

SkyGuy wrote:"Are you saying you'd rather fly a single than a twin? Now I see where you guys are coming from and on the whole I agree, but I think that like all aspects of flying, if you are smart about it, you can get the added benefit of the extra engine and extract even more utility from your flying with an increased margin of safety.

Yes, the more you have the more can fail, but that extra engine could very well save your life. Let's say you can't even maintain altitude. Your 'glide' ratio in a twin with a failed engine will beat the pants off an single with a failed engine anyday, making an off or on airport forced landing a much safer ordeal due to the simple fact that you will have more places to chose from should that engine quit."

I'd like to throw in my two cents on the topic...Skyguy is right with the above statements. As long as you are smart about it, as Skyguy stated, you will probably be OK. However, I also agree with other posts regarding the danger of light twins. Many rich (dentists/doctors, fill in the blanks) might feel that a twin is always safer than a single engine when it comes to engine failure and this is not true at all. Twins less than 6000 lbs don't have to and most cannot climb with a single engine. We all know this. What some people do not know is that many will stall or out of control upon losing an engine IF you are flying (with two engines) just above stall speed. The reason is that your Vmca (min controllable speed in air) is often much HIGHER than two-engine stall speed. Many accidents were attributable to this phenomenon during flight training as the student/instructor would be in pattern altitude, flying slow just above stall speed then practice failing an engine and get in a spin. Some do not know that twins don't have to recover from a 1 turn spin like the single is required and most will not get out of a spin.

Regards,
Nut



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