Flying overweight
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If there aren't any there go and buy some.
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Average weight
I see there's a thread running in the "Tech queries" section about calculating passenger weights.
It seems the airlines are probably more guilty of flying overweight than private flyers.
DO.
It seems the airlines are probably more guilty of flying overweight than private flyers.
DO.
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It also left me wondering just how forgiving the limits are - I had a couple of female passengers who were quite uncomfortable about giving their weight & a chap who didn't know his, so short of installing scales in the club ....
Look, it's dead easy. If she won't tell you her weight it's "sorry, then we can't go flying". Simple as that. And if you suspect she's lying about her weight, then don't take her flying. There's no way I want a passenger who refuses to take my safety instructions seriously - best to find out on the ground, I think.
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Yes,
and put a different way, you can say to such passengers:
"If I have the information to accurately calculate the total aircraft weight, I can fly it the way it was designed. Other than that, it's a test flight, and I cannot assure safety. Would you like to go on a test flight, or shall we fly it safely, the way it was designed?"
This theme also works well for passesngers who are unwilling to wait for last minute maintenance to be completed.
Pilot DAR
and put a different way, you can say to such passengers:
"If I have the information to accurately calculate the total aircraft weight, I can fly it the way it was designed. Other than that, it's a test flight, and I cannot assure safety. Would you like to go on a test flight, or shall we fly it safely, the way it was designed?"
This theme also works well for passesngers who are unwilling to wait for last minute maintenance to be completed.
Pilot DAR
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I do a lot of flying with different people and I'm always upfront with them young & old, male and female. Always start the briefing with "ok, I get to ask you a really personal question.....how much do you weigh?" It's never been a problem as they're always told it's a safety issue. We also keep a set of scales handy if we're in any doubt (quite often being underweight in the front seat can be a problem!).
I really don't understand the attitude of pilot's who're willing to fly outside the limits of the aircraft's envelope. If you're ok to fly beyond Max AUW, are you ok to exceed VNE, G-loadings, max temps, etc, etc ? I'd be quite concerned about a pilot's judgement if he or she felt that they 'know' an aircraft better than its designer. Also be concerned if exceeding weight limits is likely to increase the fatigue rate of an airframe - so it might be fine for your flight but you've just overstressed it for the next person.
In this age of ever increasing litigation and insurers seeking any loopholes to avoid paying out, flying outside the aircraft's limits isn't worth it from a financial perspective nor from a personal responsibility viewpoint either.
I really don't understand the attitude of pilot's who're willing to fly outside the limits of the aircraft's envelope. If you're ok to fly beyond Max AUW, are you ok to exceed VNE, G-loadings, max temps, etc, etc ? I'd be quite concerned about a pilot's judgement if he or she felt that they 'know' an aircraft better than its designer. Also be concerned if exceeding weight limits is likely to increase the fatigue rate of an airframe - so it might be fine for your flight but you've just overstressed it for the next person.
In this age of ever increasing litigation and insurers seeking any loopholes to avoid paying out, flying outside the aircraft's limits isn't worth it from a financial perspective nor from a personal responsibility viewpoint either.
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...and what about older aircraft which don't perform to book figures any more?
I rented a 4 seater once, was within W&B limits and only just managed to clear the boundry fence with the stall warning blaring. That aircraft certainly wasn't.
I always added a big safety margin now on aircraft I didn't know well after that.
I rented a 4 seater once, was within W&B limits and only just managed to clear the boundry fence with the stall warning blaring. That aircraft certainly wasn't.
I always added a big safety margin now on aircraft I didn't know well after that.
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I rented a 4 seater once, was within W&B limits and only just managed to clear the boundry fence with the stall warning blaring. That aircraft certainly wasn't.
Went back to the club, went through the W&B with the CFI, he agreed we were were 50lbs below gross.
CFI was very decent about it and refused to charge me for the Hobbs time, as he said good airmanship lead to the reject and he wanted to encourage safe flying.
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It is my opinion that the age, tiredness, or model of an aircraft are not factors in it's performance relative to others of the same type. It's maintenance condition could be a factor, if maintainers had allowed the aircraft to no longer conform to its required standards on it's type certificate data sheet. The pilot could be if he or she over/incorrectly loads it, or flies it with poor technique.
If you loaded it properly, and are flying it properly, and it is not performing, don't ask it's age, tiredness, or model, ask if conforms as it should. Low engine cylinder compression, mag timing way off, induction problems, wrong prop pitch, flying surface out of rig (among other causes) can all make a huge difference in performance. I delived a Lake LA-4-200 not long ago, which seemed a poor performer, but flew straight. It flew straight because someone had rigged out some great geometery problem, by rigging the right aileron 1.5" trailing edge up, which the other one was in trim. I would thus suspect that a wing was on incorrectly, that won't help the takeoff performance much! I snagged the plane, did not hear the outcome...
I think that flying technique can produce poor performance more quickly and obviously than overloading. Or phrased differently, an overloaded plane could be skillfully flown (but I'm not endorsing it), and produce performance which was seemingly acceptable. The PA28 cited earlier is a fine plane, but can be easily flown well behind the power curve on a poorly executed takeoff, and indeed, simply not climb at all. I have experimented with this on a frozen lake (miles long smooth flat runway). When abused, it just would not climb away with full power - stuck in ground affect. It had to be landed back at near full power. I've also been a very scared right seat passenger riding through a poorly executed takeoff in a 180hp PA28 Arrow. The only way a climbout happened in time, was that I retracted the gear. Everything about that plane was fine, it was totally poor pilot technique. Aircraft which are equipped with stabilators rather than stabilizer/elevator, seem to me to be able to get into a very high drag/stalled stabilator situation with application of lots of pitch up command. The early Cessna Cardinals had an AD associated with this.
There are many factors which go into causing a poor takeoff, don't just blame the plane, and decide not to learn what else could be better next time.
Pilot DAR
If you loaded it properly, and are flying it properly, and it is not performing, don't ask it's age, tiredness, or model, ask if conforms as it should. Low engine cylinder compression, mag timing way off, induction problems, wrong prop pitch, flying surface out of rig (among other causes) can all make a huge difference in performance. I delived a Lake LA-4-200 not long ago, which seemed a poor performer, but flew straight. It flew straight because someone had rigged out some great geometery problem, by rigging the right aileron 1.5" trailing edge up, which the other one was in trim. I would thus suspect that a wing was on incorrectly, that won't help the takeoff performance much! I snagged the plane, did not hear the outcome...
I think that flying technique can produce poor performance more quickly and obviously than overloading. Or phrased differently, an overloaded plane could be skillfully flown (but I'm not endorsing it), and produce performance which was seemingly acceptable. The PA28 cited earlier is a fine plane, but can be easily flown well behind the power curve on a poorly executed takeoff, and indeed, simply not climb at all. I have experimented with this on a frozen lake (miles long smooth flat runway). When abused, it just would not climb away with full power - stuck in ground affect. It had to be landed back at near full power. I've also been a very scared right seat passenger riding through a poorly executed takeoff in a 180hp PA28 Arrow. The only way a climbout happened in time, was that I retracted the gear. Everything about that plane was fine, it was totally poor pilot technique. Aircraft which are equipped with stabilators rather than stabilizer/elevator, seem to me to be able to get into a very high drag/stalled stabilator situation with application of lots of pitch up command. The early Cessna Cardinals had an AD associated with this.
There are many factors which go into causing a poor takeoff, don't just blame the plane, and decide not to learn what else could be better next time.
Pilot DAR
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Just something to be aware of!
In the UK aircraft that previously required a 3 year CofA (known as a star-annual) needed an air-test to be conducted by a CAA test pilot or someone approved by them. Part of this test was a 5 minute climb at best rate of climb speeds, the results could then be compared with the POH figures and remedial action taken if necessary. IMO this was a good indicator of the aircraft's performance. Now similar aircraft requiring EASA ARCs are not required to perform this test.
As an aside, the Cessna 150/2 had/have an automatic write-down by the CAA of some 80 fpm (from memory) which would also naturally affect the t/o distance etc.
As an aside, the Cessna 150/2 had/have an automatic write-down by the CAA of some 80 fpm (from memory) which would also naturally affect the t/o distance etc.
Last edited by jxk; 17th Jul 2008 at 06:54.
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As jxk says the UK STAR annual was a tri yearly inspection and a club aircraft can add a lot of hours in 3 years, with resultant loss in engine performance (lower compression etc), so the average Joe PPL had no real way of knowing whether the aircraft would deliver book performance, other than by familiarity with the aircraft or finding a gross fault during the walk around (e.g. incorrect rigging, which I have also found)
If you look at the performance variation across an old fleet, I imagine that the standard deviation will be of greater magnitude than for a new fleet, simply because of the impact of factors such as engine state, paint finish, prop condition, hangar rash etc.
An aircraft at the negative tail of the distribution is what I would define as "tired."
I think that is what Squeegee Longtail is saying and I agree with his cautious approach.
And I do also agree with you that handling skills are a critical factor in achieving book performance.
As jxk says the UK STAR annual was a tri yearly inspection and a club aircraft can add a lot of hours in 3 years, with resultant loss in engine performance (lower compression etc), so the average Joe PPL had no real way of knowing whether the aircraft would deliver book performance, other than by familiarity with the aircraft or finding a gross fault during the walk around (e.g. incorrect rigging, which I have also found)
If you look at the performance variation across an old fleet, I imagine that the standard deviation will be of greater magnitude than for a new fleet, simply because of the impact of factors such as engine state, paint finish, prop condition, hangar rash etc.
An aircraft at the negative tail of the distribution is what I would define as "tired."
I think that is what Squeegee Longtail is saying and I agree with his cautious approach.
And I do also agree with you that handling skills are a critical factor in achieving book performance.
Last edited by Final 3 Greens; 17th Jul 2008 at 08:58. Reason: Add definition of tired
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I think that "old" should not be a factor in performance. Tired in this context would equal poorly maintained. I am not familiar with the 3 year C of A standards of the UK. I am aware though, that if the aircraft is being maintained as specified by it's manufacturer, it will be having inspections at intervals of about 100 hours, which will include a check of engine cylinder compression, mag timing (the two of which are probably the fastest ways to get an engine to preform less well), as well as rigging, and other defects which could rob performance. Waiting three years to inspect for these defects is just poor. and it's certainly is well within the scope (and responsibility) of the pilot to satisfy him/her self that the aircraft has a record of suitably recent maintenance, to cause the pilot to believe that such defects would have been caught.
A part of the process which is involved in the setting of maintenance intervals by manufacturers is the evaluation of the lenght of time a defect could safely go undetected, without causing a safety (performance) concern. 100 hours seems to be a general standard. Certainly annually is!
Think of an aircraft as a collection of parts all pulling together. The old aircraft could have a brand new engine and prop. I used to fly a Cessna 207 with more than 19,000 hours. Paint was smooth but poor looking. Excellent maintenance, zero time engine (though probably "old"), and prop. Performed beautifully during my many fligh tests, to as high as 17,500 feet in a hard climb.
Pilot checks the condition of the aircraft both logbooks and walk around, then flies it in accordance with the flight manual and good practice, and it's going to perform properly.
Pilot DAR
A part of the process which is involved in the setting of maintenance intervals by manufacturers is the evaluation of the lenght of time a defect could safely go undetected, without causing a safety (performance) concern. 100 hours seems to be a general standard. Certainly annually is!
Think of an aircraft as a collection of parts all pulling together. The old aircraft could have a brand new engine and prop. I used to fly a Cessna 207 with more than 19,000 hours. Paint was smooth but poor looking. Excellent maintenance, zero time engine (though probably "old"), and prop. Performed beautifully during my many fligh tests, to as high as 17,500 feet in a hard climb.
Pilot checks the condition of the aircraft both logbooks and walk around, then flies it in accordance with the flight manual and good practice, and it's going to perform properly.
Pilot DAR
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The flying school I attended some years ago bought about six fr152s new. They all performed slightly differently but one was a dog. Over the period thousands of hours use, replacement engines and propellers it was always the dog of the fleet. It was eventually written off in an accident where it failed to climb sufficiently. It presumeably always managed to scrape through the climb test!
DO.
DO.
Your average 30 to 40 yr old small Piper or Cessna will almost inevitably have an accumulation of small faults such as:
-Less than perfect rigging
-minor wing leading edge dents
-slightly undersized propeller because of loss to propeller dressing
-lower engine compressions
-Mag timing which is slightly retarded
- engine and flight instruments which have developed small errors
etc-etc
Non of the above faults are serious enough to render an aircraft unairworthy or imply poor maintainance or neglect they are just the reality in a heavily used club aircraft. Individually each item will have an insignificant effect on performance but collectively they will reduce performance which is significant on aircraft which in general do not have a lot of excess performance to begin with. All of the POH numbers are devleoped from a new aircraft flown by a factory test pilot. Therefore I think a heathy extra margin should be added to any calculated performance. I would suggest any flight that is calculated to be within the POH range but at the edge of the envelope should be looked at carefully wiht a view to finding ways to increase the margins.
Finally as an instructor I found that human nature means that everyone will sometimes get a little sloppy in their aircraft handling. Most of the time it doesn't matter if the ball is little bit out of the cage or the climb speed is 3 kts too fast but if you need to get the most out of your airplane you must fly it exactly. If you are going to be conducting a takeoff in more a demanding situation a pretakeoff self briefing reminding yourself of what you need to do is a good way to get in the right mental state so you are at the top of your game.
-Less than perfect rigging
-minor wing leading edge dents
-slightly undersized propeller because of loss to propeller dressing
-lower engine compressions
-Mag timing which is slightly retarded
- engine and flight instruments which have developed small errors
etc-etc
Non of the above faults are serious enough to render an aircraft unairworthy or imply poor maintainance or neglect they are just the reality in a heavily used club aircraft. Individually each item will have an insignificant effect on performance but collectively they will reduce performance which is significant on aircraft which in general do not have a lot of excess performance to begin with. All of the POH numbers are devleoped from a new aircraft flown by a factory test pilot. Therefore I think a heathy extra margin should be added to any calculated performance. I would suggest any flight that is calculated to be within the POH range but at the edge of the envelope should be looked at carefully wiht a view to finding ways to increase the margins.
Finally as an instructor I found that human nature means that everyone will sometimes get a little sloppy in their aircraft handling. Most of the time it doesn't matter if the ball is little bit out of the cage or the climb speed is 3 kts too fast but if you need to get the most out of your airplane you must fly it exactly. If you are going to be conducting a takeoff in more a demanding situation a pretakeoff self briefing reminding yourself of what you need to do is a good way to get in the right mental state so you are at the top of your game.
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What I find truly puzzling is the double standard that is so common within the flight training industry.
The industry puffs their chests about teaching it right the first time and blathers on and on about how those things first learned are those things longest remembered or something close to that description.
Yet many instructors fly Cessna 150's and 152's over gross weight when training people....why is this so common?
And more important why is it condoned?
The industry puffs their chests about teaching it right the first time and blathers on and on about how those things first learned are those things longest remembered or something close to that description.
Yet many instructors fly Cessna 150's and 152's over gross weight when training people....why is this so common?
And more important why is it condoned?
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No contention implied.
Pilot DAR
I should have also mentioned that in the UK as well as the * annual there is an annual, 50hr/ 6 month checks. Compression and mag checks are made at the annual. However, if you take a look at Teledyne manuals you see that they say that a compression check is only of variable use. I still like the idea of the test flight which is a practical way of getting a feel for the real performance of the aircraft.
I should have also mentioned that in the UK as well as the * annual there is an annual, 50hr/ 6 month checks. Compression and mag checks are made at the annual. However, if you take a look at Teledyne manuals you see that they say that a compression check is only of variable use. I still like the idea of the test flight which is a practical way of getting a feel for the real performance of the aircraft.
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Chuck - I think the reason is that, in the UK, most people training are as broke as a rat in Baghdad. Many have to save up for each lesson, and can't have the next one until they have saved up for the next one.
Somehow, the training business has to live off this kind of scene, and it isn't easy. I walked out of one flying school due to crap (dangerous) maintenance, and that company had an AOC for public transport.
It isn't 'condoned' as such; more like the customers cannot tell.
And right now things are pretty bad here due to the big fuel price increases.
Somehow, the training business has to live off this kind of scene, and it isn't easy. I walked out of one flying school due to crap (dangerous) maintenance, and that company had an AOC for public transport.
It isn't 'condoned' as such; more like the customers cannot tell.
And right now things are pretty bad here due to the big fuel price increases.
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Just to answer the question posed earlier about whether or not it is illegal to fly overweight - it is in breach of the ANO article 52, which is the article requiring the commander of the aircraft to ensure that the aircraft is correctly loaded, etc etc. If you are in breach of the ANO you are almost certainly in breach of your insurance policy which usually states specifically that it is a condition of the insurers' obligation to indemnify that all regulations including the ANO are complied with.
As an instructor I am always horrified at the number of people who regularly overload their C152s and PA28s. If it was a helicopter you would soon know about it if you overloaded it because you would end up overtorquing and causing significant damage. In aeroplanes, consistent overloading leads to insidious stress to the airframe and quite likely propagation of cracks and fatigue failures. Difficult to measure but I am sure that a metallurgist would come up with some scientific data.
Fortunately I do not usually compromise my student's weight and balance as I only weigh 130lbs. I also have no problem with 18 stone fatties in telling them they will have to learn on a bigger aeroplane - anyway it must be so uncomfortable trying to squeeze in to a C152 with all that bulk, let alone the discomfort for the other person being shoved in to the side of the door as Fatso overspills his seat entitlement. So if you cannot afford to learn to fly in a larger more expensive aeroplane, then I suggest a rigorous diet would be a good idea and you will also save a lot of money from eating less, which could go in to the flying money pot.
As an instructor I am always horrified at the number of people who regularly overload their C152s and PA28s. If it was a helicopter you would soon know about it if you overloaded it because you would end up overtorquing and causing significant damage. In aeroplanes, consistent overloading leads to insidious stress to the airframe and quite likely propagation of cracks and fatigue failures. Difficult to measure but I am sure that a metallurgist would come up with some scientific data.
Fortunately I do not usually compromise my student's weight and balance as I only weigh 130lbs. I also have no problem with 18 stone fatties in telling them they will have to learn on a bigger aeroplane - anyway it must be so uncomfortable trying to squeeze in to a C152 with all that bulk, let alone the discomfort for the other person being shoved in to the side of the door as Fatso overspills his seat entitlement. So if you cannot afford to learn to fly in a larger more expensive aeroplane, then I suggest a rigorous diet would be a good idea and you will also save a lot of money from eating less, which could go in to the flying money pot.
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PilotDAR
Can we agree on this?
Old does not necessarily = tired (e.g the 207 you mention, sounds like a nice a/c)
Tired does not necessarily = old (e.g. I have flown aircraft less than 5 years old with lots of hangar rash, big wear & tear)
Tired = does not deliver the expected performance, maybe through poor maintenance, maybe because the wear and tear has accumulated over time, like Big Pistons Forever says.
Can we agree on this?
Old does not necessarily = tired (e.g the 207 you mention, sounds like a nice a/c)
Tired does not necessarily = old (e.g. I have flown aircraft less than 5 years old with lots of hangar rash, big wear & tear)
Tired = does not deliver the expected performance, maybe through poor maintenance, maybe because the wear and tear has accumulated over time, like Big Pistons Forever says.