Go Back  PPRuNe Forums > PPRuNe Worldwide > The Pacific: General Aviation & Questions
Reload this Page >

Partnavia crash at Rottnest Island

The Pacific: General Aviation & Questions The place for students, instructors and charter guys in Oz, NZ and the rest of Oceania.

Partnavia crash at Rottnest Island

Old 16th Nov 2006, 20:53
  #61 (permalink)  
 
Join Date: Jan 2006
Location: Australia
Posts: 309
Likes: 0
Received 0 Likes on 0 Posts
Chuckles,

Full marks on your penultimate post. THATS the sort of stuff guys like LJ need to hear.

Cheers,

Di
Diatryma is offline  
Old 16th Nov 2006, 21:25
  #62 (permalink)  
 
Join Date: Jul 2005
Location: australia
Posts: 259
Received 0 Likes on 0 Posts
Chimbu, I take in everything you said and appreciate your knowledge, and I stress I am not nit picking here, but shouldn't you lift up the dead engine a little, ie 3 to 5 degrees angle of bank towards the operating engine?
flywatcher is offline  
Old 17th Nov 2006, 00:17
  #63 (permalink)  

Don Quixote Impersonator
 
Join Date: Jul 1999
Location: Australia
Age: 77
Posts: 3,403
Likes: 0
Received 0 Likes on 0 Posts
Chuckles and Centaurus

Classic PPRuNe.

Flying ME piston is VERY serious business...there is just no room for BS.
they are NOT designed NOR required by certification to demonstrate more than a +ve rate of climb (defined as +50fpm) with an engine feathered and cleaned up. Actually waaaay more serious than in a Transport Category aircraft.

Under certain conditions of weight temp etc, some MAY do a bit or even a lot better but it is NOT "gauranteed" as it is in Transport Category aircraft.

Chuckles talks about "mind set" = when it does happen = you are in fairly deep do do = read both his last posts and throw out of your head any other form of voodoo crap or witchcraft you may have been taught or at the very least rethink it.

The statistics are brimfull of the dead dudes who imagined they knew better.

I watched the entire sequence of what most would think was a fairly powerful twin EFATO to its fatal conclusion, whilst I was physically and mentally trying to will the pilot NOT to attempt what was clearly going to take him to his death. He was a dead man the moment he started the turn to return at around 200ft. And most would have considered him very experienced.

As an aside I came to PPRuNe as a result of reading a post about a C421C accident in Glasgow that took out the two crew and the deadheading flight crew and FA's, many many moons ago. The resulting somewhat heated discussion revealed the dearth of knowledge on this subject at the same time as changing the crew deadheading policies of a number of the major UK airlines.

Last edited by gaunty; 17th Nov 2006 at 00:20. Reason: add a bit
gaunty is offline  
Old 17th Nov 2006, 00:21
  #64 (permalink)  

Grandpa Aerotart
 
Join Date: Jun 2000
Location: SWP
Posts: 4,583
Likes: 0
Received 2 Likes on 2 Posts
Flywatcher thanks for picking that up...you're correct. I was posting tired and didn't proof read it well enough before hitting submit..I went to bed instead.

As another example of what aeroplanes will do as opposed to what legend would have you believe I once had an engine failure in an Aerostar..again like the C402 and 404 mentioned previously I was heavy.

The failing engine was accompanied by an engine fire warning as the MP fell away to a near useless level...a little above the zero thrust figure I used in training.

I kept everything firewalled, raised the 'dead' engine a bit and kept the ball centered (actually a smidge out with the raised engine) and watched the left engine cowl for signs of fire...there were none..no bubbling paint or ****e exiting behind...so I kept it running..it wasn't doing me much good but it was certainly doing a little. Despite being very heavy the aeroplane had climb performance and I made circuit height reasonably quickly before turning downwind, securing the engine and landing....It was never on fire but part of the failure was the exhaust manifold falling off the engine and blowing hot exhaust fumes on the fire probe.

The Deathstar has a well deserved reputation for being a demanding aeroplane to fly...but it also has just about the best SE performance of any piston twin...flown well. I would rather have an engine failure on takeoff in a Aerostar than any other piston twin.

I endorse completely what Centaurus says about checking stuff and writing it up if required. The Islander had a main fuel system near identical to the PN68 with selectors in the ceiling and some had tip tanks...although obviously better designed than the PN68 because I never saw one stick...it did happen occassionally though...it was part of the first flight of the day ritual to exercise and test the entire system (on every piston twin I ever flew). If you have an engine fire that you cannot put out the wing spar can burn through on most piston twins in less time than it can take to climb up to 500' on one engine.

To test the shut off turn the fuel off after the last flight of the day, every day, and after it dies pull the mixture to idle cut off. Leave it off...if the next joker (you with a hangover? )doesn't do his cockpit set up correctly he won't be able to start it. If you find you can't shut the engine down with the fuel cock you just might be saving the next pilots life..and those of his pax....if you write it up on the MR.

PS: 17 yr old boys are just a life support system for an erection

Last edited by Chimbu chuckles; 17th Nov 2006 at 01:49.
Chimbu chuckles is offline  
Old 17th Nov 2006, 03:36
  #65 (permalink)  
 
Join Date: Nov 2006
Location: Oz
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
Chuckles,

Thanks for debunking the myth about light twin single engine performance. I have limited experience on light piston twins and less on piston singles (happily). I have endorsements on the Dutchess, Baron and Partnavia and, despite being told endlessly that they would not fly well on one engine, found them to be quite docile in the EFATO situation. Certainly, in comparison to a double EFATO in the Herc (which isn't done any more, for good reason) the light twins I have flown require less draconian recovery action, less physical effort and perform OK.

I am always worried, if not terrified, when I go to do a twin endorsement because I am not inspired by the blurring of myth and fact in many areas of GA. When doing the Partnavia endorsement over Phillip Island, the instructor wanted me to slow to Vmca when it was only about two knots away from the stall speed. That scared me and I refused to do it, suggesting that we should instead simulate the Vmca symtoms by limiting rudder input to give us a margin above the stall. When doing the Baron endorsement the instructor insisted that I did not input aileron to maintain wings level when approaching Vmca. That left us rolling and yawing close to the stall and guess what; we entered a spiral dive. The instructor was actually more scared than me becuase I was at least half expecting it.

On another occasion I wrote the flap system up as unserviceable on a Baron that I had private hired. When it wasn't fixed on the third occasion I complained and was told by a commercial pilot operating in that company that the system was supposed to operate in that manner. A quick check of the POH revealed that it wasn't at all.

I am concerned that some junior pilots are far too willing to accept the advice of the 'more experienced' pilots in their fields without researching the veracity of that information. In some instances the 'more experienced' operators are free from the checks and balances that would require them to validate their own opinions and they become self verifying.

Back to the topic though, I see the media report refers to mechanical failure but doesn't mention engines. Also, there is no mention in the report of witnesses hearing unusual engine noises (something that almost always seems to make the reports). The reason I ask is that I remember being told of a design fault in the Partnavia where the elevator torque tube was clamped to the actuator but not pinned. That could lead to the torque tube slipping and a resultant loss of elevator authority. Does anyone know if that fault actually existed and if it was subject to a required modification?
Barry Bernoulli is offline  
Old 17th Nov 2006, 03:46
  #66 (permalink)  
 
Join Date: Mar 2004
Location: Melbourne
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Chimbu...

I take your experiences and your method of teaching on board and believe it would work well for guys that already have some degree of experience before they jump into a twin. But unfortunately as you said yourself that those teaching new students barely have enough experience to pass on the correct technique let alone the students themselves. The new guys getting endorsed on a baron or seminole might have all of about 150hrs total. 150hrs may be sufficient experience to meet a standard in a controlled environment but when something goes wrong...? Unfortunately these days if a student doesn't meet the standard the instructor or the school gets the blame.

When I did my first twin endorsement my instructor had over 8000 hours. I believe what he was getting at with the "close both throttles" is that at the stage where I was at, I honestly didn't have the experience to be able to handle an engine failure at 50ft whilst waiting for a positive ROC. Unfortunately most students will have their head inside the cockpit trying to make sure they pull the correct levers and trying to locate the flap switch. All the while the aircrafts speed is rapidly decaying as it gets closer and closer to the ground and blue line. This all takes a lot longer for someone with minimal total time and time on type. The point I make is that in a real life engine failure on a hot day at MTOW I doubt that many instructors could honestly say that their students would definitely pull it off. It is for this reason that it is better for the student to simply close both throttles and land instead of letting the aircrafts speed reduce below VMC. Look what happened to the instructor/student who tried to go around when the prop was feathered on short final when the student pulled out onto the runway (somewhere on the east coast a few years ago)?

I agree that sooner or later a perfectly serviceable aircraft will EVENTUALLY reach a positive ROC but there are so many other factors involved here. Was the aircraft climbing/descending/approach configurations/how low was it to the ground and was it developing slightly less power on the live engine? What caused the engine failure and will the prolonged higher power setting cause the second engine to fail? Remember the cracked crank shaft of both engines in the Chieftain some years ago? There are small hills to the west of Rottnest (difficult for a successful forced landing) so pinning blue line speed for however long it takes to achieve a positive ROC might just send you into the side of a hill... Maybe the pilot made the correct decision by aborting and putting her down on what he thought was a good spot.

This all brings me to another interesting point and hopefully Chimbu can comment on this too (hopefully he doesn't take my comments personally). What does everyone use for a decision point in a LIGHT PISTON TWIN? I have realised that many new pilots coming through were taught blue line speed, or gear up or a height for a decision point. These all work well if they are used correctly and smartly. For example, hopefully you wouldn’t use blue line speed on a hot and heavy day... 1. An engine failure has to be recognized and reacted to (2-3 secs) 2. It has to be dealt with (7 secs) and 3. It has to be feathered (5-10 secs). All this takes time, imagine if the blue line speed is 90kts, the pilot suffers an engine failure at maybe 95kts in a nose high attitude on a hot and heavy day. That speed is going to wash off extremely fast to below blue line speed while the pilot deals with the engine failure (we’re not talking about some test pilot situation we’re talking about an everyday pilot). NOW the aircraft has to accelerate on one engine TO blue line speed… See my point? I vary my brief to each individual take off and hope that all other pilots do also. Personally I have found that blue line plus 10kts works well in most situations. Thoughts anyone?
locknut is offline  
Old 17th Nov 2006, 04:59
  #67 (permalink)  
 
Join Date: Oct 2005
Location: somewhere in Oz
Age: 54
Posts: 913
Likes: 0
Received 1 Like on 1 Post
Locknut, you're not making much sense to this SEP pilot. Whilst I know nothing about flying multi's, surely if you have any EFATO, wouldn't the first task be get yourself an attitude that, at the very least, maintains your airspeed?

If you fiddle with your engine controls before doing this, you are doomed to a sudden high ROD, even in a single!

A
Andy_RR is offline  
Old 17th Nov 2006, 06:51
  #68 (permalink)  
 
Join Date: Mar 2004
Location: Melbourne
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Well obviously I don't make much sense if you don't read what I have actually written.

"Unfortunately MOST STUDENTS" or even inexperienced pilots will have their head inside the cockpit.

Clearly we don't have to go back to basics regarding attitude and airspeed do we? I think we all know that power + attitude = performance (being our airspeed in this case). But the book does not publish an attitude does it... it mentions a speed. You're totally correct in saying that we maintain an attitude not a speed but I guess it is just a way of making things easier to explain rather than going into too much detail.
locknut is offline  
Old 17th Nov 2006, 07:11
  #69 (permalink)  
 
Join Date: Mar 2004
Location: Melbourne
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
One thing I forgot to mention...

Lets see if I can remember this as its been a while. In order for an aircraft to climb, the thrust must exceed the drag. Now shortly after take off the aircraft has the gear and possibly some flap out also, the drag is very high. Suddenly the thrust is reduced by half and the gear and possibly flaps are still extended. Additionally if you are unliky enough the engine is not developing partial power but a complete engine failure exists so control forces are required further increasing drag whilst you try and pull through the air a spinning flat disk attached to the wing (engine and propeller). Normally, there is now insufficient thrust to even maintain level flight with the gear and maybe flaps out. Obviously the only thing the pilot can do is lower the nose. But this all happens very quickly, the pilot tries to keep the nose straight and then remembers to lower to nose. So to even contemplate attempting a climb the pilot must:
1. Recognise that an engine failure has occured
2. Clean up the aircraft and Identify the failed engine
3. Feather the failed engines propeller
Only then, a climb maybe possible after taking into consideration many other factors beyond the pilots control.
locknut is offline  
Old 17th Nov 2006, 07:11
  #70 (permalink)  
 
Join Date: Oct 2005
Location: somewhere in Oz
Age: 54
Posts: 913
Likes: 0
Received 1 Like on 1 Post
Originally Posted by locknut
...imagine if the blue line speed is 90kts, the pilot suffers an engine failure at maybe 95kts in a nose high attitude on a hot and heavy day. That speed is going to wash off extremely fast to below blue line speed while the pilot deals with the engine failure (we’re not talking about some test pilot situation we’re talking about an everyday pilot
I didn't mean anything about the Stude example you gave. I meant this one! Surely if you're at 95kt and climbing at the point of EFATO, the best course is to preserve your 95kt, before you deal with any engine controls, no? No point in falling out of the sky with a properly feathered prop, is there?
Andy_RR is offline  
Old 17th Nov 2006, 07:15
  #71 (permalink)  
 
Join Date: Nov 2006
Location: Oz
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
locknut,

This is not intended to tell anyone to suck eggs and most of this is statinf the obvious.....

I've pulled out the POH for the BE58 as an example. In Section X - Safety Information it says in the introduction, 'The skilled pilot recognises that safety is an integral - and never ending - part of his or her job.........Maintain your currency and fly with a qualified instructor until you are qualified and proficient' (my emphasis). Further on it says, 'The major difference between flying a twin-engine and single-engine aeroplane is knowing how to manage the flight if one engine loses power for any reason. Safe flight with one engine inoperative requires an understanding of the basic aerodynamics involved - as well as proficiency in engine out procedures' (my emphasis again).

So in response to the first portion of your post; regardless of what the flying school or instructor allows, anyone who wants to survive to go fishing with their kids on Saturday should not accept an endorsement before they are comfortable and proficient with the correct procedures for handling an emergency; forget about 'never mind if you're not up to it, you can do this instead' plan. OK, Utopian thinking, I agree, for the average cash-strapped young wannabe.

I don't believe in aborting airborne. An abort is a rejected take-off. Once I'm airborne it is a forced landing.

In regard to the decision point, it comes back to the POH. What does the POH (ie, the highly paid and proficient test pilots, the company litigation lawyers and the FAA/CASA) say. Again, back to Section X of the POH, it says (for the BE58) 'Know and follow, to the letter, the single-engine emergency procedures specified in your Pilot's Operating Handbook and FAA approved flight manual for you specific make and model airplane.' It then talks about generic principles and then refers the user back to the wealth of information available in the various graphs and tabulated data.

Assuming VMC/VFR: The TAKE-OFF WEIGHT graph will tell me whether I can achieve a positive single engine rate of climb at lift-off with (in this case) flaps up and gear down. If I can climb away then I would look at the ACCELERATE - STOP graph to see if an abort at lift-off is going to leave me with enought runway to stop and add that gem to my brief. If I can't climb away at lift off I would consider the TAKE - OFF DISTANCE graph to give me an idea of what distance it will take me to reach the single engine climb speed and also look at the LANDING DISTANCE graph from 50ft, add those distances together and then visually assess the chances of a safe forced landing in that area of the take-off path and, if I think I can put it down safely in that area, add that to my brief. The next stage is to assess my single engine climb performance at single engine climb speed to see what gradient I can make and assess, visually or mathematically, whether that will keep me clear of terrain. I then add that component to my brief. If I am unsure as to the safe outcome of any portion of the take-off, on the balance of risk, I will take steps (reduce weight/wait/change departure direction) to make it safe or I will not go.

So the decision speeds and procedures are as per the POH: lift-off (abort or continue) and single engine climb speed (fly away or conduct a forced landing). the brief will be: 'Prior to lift-off I will abort and the result will be ......... After lift-off and prior to single engine climb speed of XXkts I will............After reaching single engine climb speed I will..........' Because I will not fly unsupervised unless I am proficient with the emergency procedures, I can make them work. There is simply no data available to make clear assessments as to what will happen in between and very few pilots have the experience in those situations to tell them.

My advice to everyone is to listen to what people have to say in these forums and in your flight schools and workplaces but don't believe anything until you validate it through the authorised publications and manuals, be proficient and above all read the POH.
Barry Bernoulli is offline  
Old 17th Nov 2006, 07:36
  #72 (permalink)  
 
Join Date: Mar 2004
Location: Melbourne
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
Very true, the first thing to do is lower the nose and keep the aircraft under control but if thats the only thing your gonna do you might as well point it at the ground cos it ain't gonna save your life.

Hopefully most pilots can multi task cos if you can't, well...
locknut is offline  
Old 17th Nov 2006, 10:54
  #73 (permalink)  
 
Join Date: Dec 2005
Location: Perth
Posts: 176
Likes: 0
Received 0 Likes on 0 Posts
Raising the dead engine

Flywatcher,

Just a thought on your comment on raising the dead engine 3 to 5 degrees.

I used to believe this to be true from what I had learned during my twin training and never questioned the accuracy of these often quoted bank angles.

That was until I started flying twins in earnest and I aquired John Ecklabars Book "Flying High Performance Singles and Twins. He devotes nearly a whole chapter to dispeling these numbers as a myth (yep another one).

In short the correct numbers according to maths and historic research outlined in his book are in fact between 1 to 3 degrees. The lower the thrust from the remaining engine the closer the correct number will be to 1 degree. Small difference but significant, as every degree greater than optimum will degrade performance by 30'/min. 4 degrees out and you would be giving away 120'/min. Also worth noting that in attaining zero sideslip the ball will not be centred in an asymetric condition.

Don't ask me how you are suppossed to judge these subtle angles.
Although the book does give some insight.

Thoroughly recommend this book for all budding professional twin drivers (and single).

Regards
M
youngmic is offline  
Old 17th Nov 2006, 12:37
  #74 (permalink)  

Grandpa Aerotart
 
Join Date: Jun 2000
Location: SWP
Posts: 4,583
Likes: 0
Received 2 Likes on 2 Posts
locnut I rarely take anything personally...so I hope you wan't take what I am about to write personally.

I found your entire first paragraph terrifying reading...particularly this bit.

The point I make is that in a real life engine failure on a hot day at MTOW I doubt that many instructors could honestly say that their students would definitely pull it off.
I can tell you without fear of contradiction that every person I ever signed out on any aircraft, including twins, was to a standard that would allow me to happily put my famly in the aeroplane with them...or they were not released. All my peers who were trainers and all the trainers who trained us took a similar view.

With good quality training from experienced trainers the % of pilots not capable of meeting that criteria was tiny...but there were a few.

It doesn't happen often but there are pilots who should not be licenced as there are drivers who should not be licenced.

As for decision points...well benouli covered it in great detail...I used to sit down and do similar calculations for a worse case situation and then I always knew I could expect at least that much performance anywhere that was less limiting...true bush strips aside...sometimes in PNG you were committed by the time you were 3 cone markers from brakes released...on a 350m/15% sloped wet grass airstrip there is just no way you will stop once you have 40kts indicating...luckily most of those style strips had falling terrain off the end...often a sheer cliff...and you could just charge off the cliff at less than flying speed and pick it up in a dive....perhaps retarding the good engine just enough to maintain directional control. Often in PNG , I did 99% of my piston single and twin time there, if you had an engine failure before 1000' above strip level you were simply going to crash and that was that...so we gave a lot of thought about how we would crash and where we would crash at specific strips...or at least I did and most of my mates did...you could virtually always cobble something survivable together.

That may well be part of the problem in Australia...crashes are so rare no one gives serious consideration to how they will do it...in PNG they were anything but rare so we gave the 'how' of crashing in various scenarios a lot of thought...and were better equiped to cope as a result.

I would go as far as to say that if you arrive under control virtually anything is survivable...water is a piece of piss. It is just a mindset.

EDIT:

Benouli I feel your pain...when I was given a Cessna Citation 560 Ultra endorsment years ago the CASA approved chap told me "If you lose an engine on takeoff retard the good engine 'a bit'."

I held, at that time, every check and training approval possible for the Falcon 200 corporate jet and had been trained initially on jets in the airlines (Air Niugini) where the required standards were high indeed.

"umm..why would I do that"

"because this aeroplane has really powerful engines and you might lose control and roll upside down"

"umm...this aeroplane is transport category certified under part 25"

"Yep"

"So V1 can't be less than VMCg or more than Vr which itself can't be less than 1.05 VMCa. V2 is at least 1.1 VMCa and 1.2 Vs...you fly those numbers and you cannot lose control"

He looked a bit like a dog watching TV..."well...if you lose one at V1 pull the other one back a bit"

"No..I won't be doing that".

Terribly nice fella...but some tw@t at CASA had listened to that drivel and said nothing.

What hope for an appropriate standard at the bottom rungs?

Many, many years ago a very experienced pilot showed me a VMCa loss of control at altitude in a Baron...it was eye watering to say the least but it wasn't a VMCa loss of control it was an assy stall. I said 'cool' let me have a go...and limited rudder input appropriately so at some speed around the published VMCa the aircraft just gently yawed away until I recovered.

The chap was flumoxed...I explained that at our present altitude the engines were producing so little power that VMCa was below stall speed...to his great credit he took it on board and, I think, stopped demoing assy stalls.

Last edited by Chimbu chuckles; 17th Nov 2006 at 13:22.
Chimbu chuckles is offline  
Old 17th Nov 2006, 13:34
  #75 (permalink)  
 
Join Date: Nov 2006
Location: Oz
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
youngmic,

continuing the theme, consult the POH.

Using the BE58 POH as an example (because it is the ony POH for a light twin that I own) the emergency procedure for engine out refers us to Section X for 'additional information regarding pilot technique'.

Section X says a couple of interesting things that xorrelate to your post. The first is that '......The net result of these forces cause the airplane to sideslip slightly towards the dead engine. This sideslip may be balanced by banking slightly (up to 5 degrees) into the operating engine.'(My underlining for emphasis). Then, in the same section it talks about the definition of Vmca which includes the phrase '....maintain straight flight, with not more than 5 degrees of bank...; (my underlining again).

There is no myth as such, except for in the way many may tell it. The sideslip angle is very bad as it reduces the effective airflow angle of incidence over the rudder, reducing the ability to counter yaw, requiring additional rudder input which further increases sideslip and thus it feeds on itself until you run out of rudder. A slight angle of bank, as the book would have indicated, tilts the lift vector to counter the sideslip vector and normalises the airflow over the rudder.

The issue is that Vmca certification requirments state that not more than 5 degrees angle of bank may be used to neutralise the sideslip. In order to fly away from the ground, you want as much of the lift vector vertical as possible. As you have indicated, the actual AOB required may be much less that 5 degrees depending on the situation. However, it is the Vmca that will kill you in the initial stages and 5 degrees is a good figure to go to (unless the POH sates otherwise) until you are happy that you are maintaining directional control and can assess the situation further. As to how you identify the required angle, I believe that the skid ball should 'point to the ground' when the sideslip is neutralised (ie, slight left bank will have the skid ball slightly left of the centre, about half to one ball). Once you get a margin above Vmca, rudder authority isn't as critical and you can trade-off sideslip to get a better rate of climb. Whether this is desireable or necessary will depend on the advice of the POH.

So, yes, the book is correct, and 5 degrees is correct as a certification figure, and for the aircraft you are flying you should always refer to the Emergency Procedures section of the POH.
Barry Bernoulli is offline  
Old 17th Nov 2006, 23:25
  #76 (permalink)  
 
Join Date: Dec 2005
Location: Perth
Posts: 176
Likes: 0
Received 0 Likes on 0 Posts
G'day BB,

Sadly the often quoted referance we see in this forum of "consult the POH often leaves the pilot none the wiser. You are indeed fortunate to own a Beechcraft, which have very good reference material.

Both the twins I fly are completely silent on the subject, and one is a turboprop.

I agree with most you have written in the previous thread, you obviously have a solid understandering of the subject matter.

As you correctly stated 5 degrees is a certification requirement. And you aknowledge the fact that it may not be the optimum AoB. At this point I would have been reluctant to then advise readers that a target AoB of 5 degrees is a good target to aim for. Given that in a low powered twin the real number would be 1 to 1.5 degrees (sorry about the decimal point it's the way the maths goes) and anything above that angle waves good bye 30'/min/degree. You may well have advised readers to put the aircraft in a configuration that results in a rate of decent. Hardly good.

Whilst I can not verify factually your comment about 1/2 to one ball out being an appropriate target, it does sound rather excessive, I would have thought a smidge might be more appropriate.
Why twins don't have a yaw string I will never know, if they did you could solve the zero sideslip issue instantly, intuitively and all while looking out the windscreen. Where precision counts you'll find them i.e. gliders.

I personally would not be bothering with refering to the slip/skid ball until I am really well clear of terrain, I bet that if I looked at it low down or early in the event all I would learn is that yes turbulance makes it slop side to side and my course intial rudder imputs whilst trying to peg an attitude and counter asymmetry make it worse.

These low and decimal point AoB figures refered to concern me, but thats the physics of it, i know that I for one would have a snow flakes chance in hell of being able to identify the correct angle. Suffice to say that if you can discern much of an AoB it is probably already to much.

Guess the answer is to spend as little time as possible in low performance twins, and have a good engine mechanic.

Regards
M
youngmic is offline  
Old 18th Nov 2006, 01:56
  #77 (permalink)  
 
Join Date: Mar 2004
Location: Melbourne
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
CC

Just a quick one...

Unfortunately, with regards to sub standard students it is becoming more and more apparent in some areas of GA. I'm not referring so much to those who work in GA in OZ, more so the schools that pump out the mass number of CPL/CIR cadets who jump straight into a widebody jet.
locknut is offline  
Old 18th Nov 2006, 02:35
  #78 (permalink)  
 
Join Date: Nov 2006
Location: Oz
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
youngmic,

I wish I owned a Baron, I only own a POH for the Baron.

My reason for advising 5 degrees, in the absence of POH advice to the contrary, is that Vmca, or directional control, is the first concern that must be overcome with an EFATO. Back to the POH; 'The most important aspect of engine failure is the necessity to maintain lateral and directional control.'

Although Vmca as published is generally below lift-off speed, that is for a pre-determined set of conditions including up to 5 degrees angle of bank towards the live engine. If sufficient AOB is not established sideslip will develop. As the sideslip develops, the angle of incidence of the airflow over the vertical stablisier decreases, decreasing the rudder effectiveness. Therefore, having insufficient bank towards the live engine can increase the conditional Vmca significantly. Whereas the static Vmca for the conditions encountered with wings level can be around 15kts above the certified figure, a proficient pilot can notice it approaching and take corrective action (but you want to be apoproaching it from above, not looking at it from below the required speed). In the EFATO case, however, the dynamic Vmca can be higher again due to yawing and rolling moments (Vmca, although usually rudder limited can be aileron limited as well).

In an EFATO the priorities are to maintain control, including directional control, maximise available power and reduce drag to allow the aircraft to accelerate to single engine climb speed. If you've done your homework you wil be using the TODA, possibly in ground effect, and any additional obstacle clear areas to do this. So in the event of an EFATO at lift-off you select an appropriate attitude to acclerate the aircraft, including 5 degrees angle of bank towards the live engine because you know that is sufficient to maintain directional control. You check max power on the live and then get rid of excess drag (feather prop, gear and flap up) as per the POH procedure. Once you've got those initial actions out of the way, have a good margin above Vmca and you have time to look out the front, then you can start thinking about obstacle clearance issues, including rolling off the bank angle to maximise climb performance. You will probably find that by the time you attain single engine climb speed you can come back to wings level and accept the decreased rudder effectiveness brought about by the sideslip. You will be slightly out of balance but will be getting even better climb performance that with your 1 to 3 degrees AOB. Once obstable clearance is sorted, then, IAW the POH procedure, you clean up the mess and think about getting back on the ground.

Although the most important thing is to look out the window (assuming you have visual reference), you need to check the skidball early to make sure you are in the ballpark. If you've had a right engine failure and your skidball is still out to the right, you will shortly be landing on your roof in a very ungraceful manner. You get the skidball to the side you need it to maintain directional control by a combination of rudder (all of it) ad AOB. If you put all the rudder in and the skidball is still on the wrong side, you need to increase the AOB towards the live. If that doesn't work, you need to increase airspeed, reduce the drag on the dead or pull some power off the live.

The main difference between what I'm saying and what you're saying is that I am emphasising that directional control is by far the most important factor in an EFATO and obstacle/terrain clearance comes thereafter as per the POH advice. You don't need the accident investigators to be impressed that you made it to 100ft before you rolled on your back and speared in. To quote Chuckles in his previous post:

I would go as far as to say that if you arrive under control virtually anything is survivable...water is a piece of piss. It is just a mindset.
Barry Bernoulli is offline  
Old 18th Nov 2006, 03:16
  #79 (permalink)  

Grandpa Aerotart
 
Join Date: Jun 2000
Location: SWP
Posts: 4,583
Likes: 0
Received 2 Likes on 2 Posts
I agree.

Perhaps the best alternative is threads like this one where upwards of 5000 views suggests, hopefully, that some good info is deseminated and gets a few META instructors thinking and asking questions.
Chimbu chuckles is offline  
Old 18th Nov 2006, 11:58
  #80 (permalink)  
 
Join Date: Oct 2002
Location: The Coal Face
Posts: 1,286
Received 316 Likes on 121 Posts
Barry & Chuck,

Your stories re assy training reminded me of the most graphic illustration of its dangers - the loss of a 707 off East Sale in the early 90s. Two QFIs practicing assymmetric handling lost control of the aircraft and spun into the ocean. A more tragic lesson I can not think of as to the dangers of 'training' for the worst.

Great posts, the most educational I've read here for a while.
Chronic Snoozer is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.