Exceeding maximum gross weight
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Exceeding maximum gross weight
I'm looking for the complete list of adverse factors relating to exceeding rotorcraft maximum gross weight - the obvious ones too. Thanks in advance for your sensible input. 
On the aircraft:
Components will not make their projected life time.
On the pilot:
The strange feeling in your gut that something will go wrong, but you don't know when.It will of course when you need it the least.
Nothing on the legal side unless you get ramp checked or something bad happens.
When it does:
-loss of life or health, pilot and/or passengers, loss of machine.
-loss of licence
-huge fines and prob. life time payments to victims
-loss of job
-loss of family
Components will not make their projected life time.
On the pilot:
The strange feeling in your gut that something will go wrong, but you don't know when.It will of course when you need it the least.
Nothing on the legal side unless you get ramp checked or something bad happens.
When it does:
-loss of life or health, pilot and/or passengers, loss of machine.
-loss of licence
-huge fines and prob. life time payments to victims
-loss of job
-loss of family
For starters
Structural overload, metal has a memory.
Performance issues, all bets are now off as you cannot use the performance graphs in the manual, theoretically you could extrapolate but what happens if you get it wrong ?
Controllability, you cannot be inside the weight and balance envelope so you may end up outside the bounds of where the aircraft is controllable, how would you know ?
And the attendant risks of overboosting a piston or overtorquing a turbine as a consequence.
Structural overload, metal has a memory.
Performance issues, all bets are now off as you cannot use the performance graphs in the manual, theoretically you could extrapolate but what happens if you get it wrong ?
Controllability, you cannot be inside the weight and balance envelope so you may end up outside the bounds of where the aircraft is controllable, how would you know ?
And the attendant risks of overboosting a piston or overtorquing a turbine as a consequence.
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It would get very cold outside, standin' out there without any insurance cover, if'n the smallest thing went wrong for any other reason and it all ended up pear shaped. Either in the hottest desert or especially way up there where the ice was all over those radio towes in the other thread.
Perhaps you could also read the latest australian crash comic, a couple of overweight fatals there for you to mull over.
Perhaps you could also read the latest australian crash comic, a couple of overweight fatals there for you to mull over.
Aircraft Grounded
Once the aircraft has been operated in an over gross state, for what ever reason, it should be documented. The list of elements that could be affected is extensive. A detailed discrepancy needs to be entered into the aircraft's maintenance records. The extent of the exceedence and flight duration of should be recorded. Ground operations should also be documented. The manufacturer will require this information to determine the extent of inspections and possible component replacement.
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On a more practical matter - you've invalidated your Certificate of Airworthiness. The CofA requires that the aircraft be operated within the limits of the Type Certificate Data Sheet (TCDS). One of those limits is weight and CG. (and the Flight Manual also has weight and CG in the limitations section).
So, exceed the maximum weight, invalidate CofA. No CofA - most probably no insurance. Also putting your license on the line.
And giving lawyers a great tool for the inevitable lawsuits is you crash...
So, exceed the maximum weight, invalidate CofA. No CofA - most probably no insurance. Also putting your license on the line.
And giving lawyers a great tool for the inevitable lawsuits is you crash...
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adverse factors relating to exceeding rotorcraft maximum gross weight
What more do you need to know?
You may have a death-wish - I'll warrant your poor pax don't. Resign!
Avoid imitations
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You have an engine failure on departure and the other one has just enough power to take you straight to the scene of the crash.
Chief Bottle Washer
I can't help but reflect on how times (and attitudes!) have changed: Bristow operations
Performance in accordance with the Flight Manual was not really practical ; the pilots stuffed the aircraft with as much fuel as they thought they could carry often departing 300lbs over max gross weight. If necessary the ship was turned to give a relative wind of 45 degrees port or starboard. On the deck the rotor blades were lower than the level of the life boats and davits, which had to be cleared on lift-off. The technique in these piston engined machines was, after cockpit checks had been completed, reduce rotor RPM to ground idle for a few seconds then increase throttle and power, lift off and go, making as little cyclic and pedal inputs as possible. Having cleared the deck dive toward the sea to build up speed and translational lift and you were on your way.
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To truly include all adverse factors be sure to include the Law of Unintended Consequences.
It states: There will always be unintended consequences.
At worst, in helicopters, this means the next poor sod and all his pax die a horrible death on what should have been a gentile and lovely pleasure trip because you failed to log that last over temp start or all those over-torque T/O's, et....etc... etc...
Now! Who among us can stare the keyboard in the face and say: "Never I, Dan" ???
Metal does indeed have a memory. Never forget, fellow pilots, every bearing, tail rotor blade and pitch link knows what you have previously asked of it. That component cannot speak to the investigator, but that is exactly why we have Tech Logs.
If you can't understand the above you have no business in a cockpit.
Dan
PS:
You know what really pisses engineers off? It's those idiots in the pub who tell you it is legal to drive 15% over the speed limit because there is a tolerance on car speedometer accuracy that permits that much error? They can't quite grasp that instrumental error is granted to the instrument maker...not the driver.
Dan
(and for those wondering, no, car instrumental error is not a permitted 15%)
It states: There will always be unintended consequences.
At worst, in helicopters, this means the next poor sod and all his pax die a horrible death on what should have been a gentile and lovely pleasure trip because you failed to log that last over temp start or all those over-torque T/O's, et....etc... etc...
Now! Who among us can stare the keyboard in the face and say: "Never I, Dan" ???
Metal does indeed have a memory. Never forget, fellow pilots, every bearing, tail rotor blade and pitch link knows what you have previously asked of it. That component cannot speak to the investigator, but that is exactly why we have Tech Logs.
If you can't understand the above you have no business in a cockpit.
Dan
PS:
You know what really pisses engineers off? It's those idiots in the pub who tell you it is legal to drive 15% over the speed limit because there is a tolerance on car speedometer accuracy that permits that much error? They can't quite grasp that instrumental error is granted to the instrument maker...not the driver.
Dan
(and for those wondering, no, car instrumental error is not a permitted 15%)
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That is a very valid point Senior pilot.
One only has to read the old australian army handling notes for the souix and you will see that it is recommended to run the RPM 100 over the the red line for those same sort of departures.
So it is not much wonder that many of us engaged in these over loading type maneuvres way back when we were flying aircraft that were NOT designed to closer tolerances and thus shorter real life by computers. The '47 blade for example was built like the provervial brick turnout.
Jumping helicopters off the ground was a trait often used, but still deplored by many even back then and it was the reasson that many people were killed, particularly in New Guinea, I.e. hot high.
Jerking the collective up was one thing, but getting yourself to an area where you could then push it down again to recover RPM was a real issue.
we certainly spent lots of time teaching people to only allow the A/C to be loaded so that it could be capable of climbing under its own merit.
Even the confined area take off technique that I and many were taught we don't teach operationally any more, certainly not to any one with less than quite some hours, as it is too risky for a miscalculation. I.E going smoothly from light on the skids to full power and immediately setting the angle of attack for the airspeed which gave you the "highest angle of sustained climb". one major problem was the before take off checks to (hopefully) ensure that the turbocharger was going to spool up for you.
which they often didn't on a hot day and the first start up at say 11.00 am after you have been collecting samples.
One only has to read the old australian army handling notes for the souix and you will see that it is recommended to run the RPM 100 over the the red line for those same sort of departures.
So it is not much wonder that many of us engaged in these over loading type maneuvres way back when we were flying aircraft that were NOT designed to closer tolerances and thus shorter real life by computers. The '47 blade for example was built like the provervial brick turnout.
Jumping helicopters off the ground was a trait often used, but still deplored by many even back then and it was the reasson that many people were killed, particularly in New Guinea, I.e. hot high.
Jerking the collective up was one thing, but getting yourself to an area where you could then push it down again to recover RPM was a real issue.
we certainly spent lots of time teaching people to only allow the A/C to be loaded so that it could be capable of climbing under its own merit.
Even the confined area take off technique that I and many were taught we don't teach operationally any more, certainly not to any one with less than quite some hours, as it is too risky for a miscalculation. I.E going smoothly from light on the skids to full power and immediately setting the angle of attack for the airspeed which gave you the "highest angle of sustained climb". one major problem was the before take off checks to (hopefully) ensure that the turbocharger was going to spool up for you.
which they often didn't on a hot day and the first start up at say 11.00 am after you have been collecting samples.
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One only has to read the old australian army handling notes for the souix and you will see that it is recommended to run the RPM 100 over the the red line
I reckon you would probably need more than an extra 100 RPM to valve bounce a 435 in a 47......... I think those overspeeds were more to do with pilots having a fast left elbow and a slow left wrist!!
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crash comic, yeah well don't believe everything that your read in a newspaper they say. although in recent years there seem to be less lapses of the imaginery and ridiculous.
Valve bounce speed will be reached following a freewheel failure. The noise is frightening, the fan throws the belts and i don't know what RPM it is but it definately stopped accelerating before i got the throttle off in a heartbeak or well less. overspeed checks did not yield anything unusual, but in strip down it was a different story.
There was another twist to it which I won't relate.
The rest was is as bellfest says, finger trouble. over 250rpm over usually rewards the engineers with some metal sample at the 75 to 100 hour mark afterwards depending on the power pulled at the time.
i remember being told to go to 3400 and bleed off if I was real stuck, which I was in a 3B2 once. The task was to lift out a crashed 3B1 from high timber at fairly high DA. we did it in two lifts.
on the second trip we loaded the litters and the hook load and left it there while I dropped the gingerbeer at a clearing about half a mile away.
Loaded with the gingerbeer his tool box and the hooked load, ect. I went to 3400 for about two seconds as we climded towards 35.5 (one inch under max for temp correction on the day) inches, and i felt I could feel the metal shredding. I gave that away and bounced it off instead from 3300 and just as we got around the corner the gingerbeer nearly sh*t himself.
right there only fifty yards from where he was were about ten very curious wild buffalo. we didn't stuff the engine, but oh so close i think.
Valve bounce speed will be reached following a freewheel failure. The noise is frightening, the fan throws the belts and i don't know what RPM it is but it definately stopped accelerating before i got the throttle off in a heartbeak or well less. overspeed checks did not yield anything unusual, but in strip down it was a different story.
There was another twist to it which I won't relate.
The rest was is as bellfest says, finger trouble. over 250rpm over usually rewards the engineers with some metal sample at the 75 to 100 hour mark afterwards depending on the power pulled at the time.
i remember being told to go to 3400 and bleed off if I was real stuck, which I was in a 3B2 once. The task was to lift out a crashed 3B1 from high timber at fairly high DA. we did it in two lifts.
on the second trip we loaded the litters and the hook load and left it there while I dropped the gingerbeer at a clearing about half a mile away.
Loaded with the gingerbeer his tool box and the hooked load, ect. I went to 3400 for about two seconds as we climded towards 35.5 (one inch under max for temp correction on the day) inches, and i felt I could feel the metal shredding. I gave that away and bounced it off instead from 3300 and just as we got around the corner the gingerbeer nearly sh*t himself.
right there only fifty yards from where he was were about ten very curious wild buffalo. we didn't stuff the engine, but oh so close i think.
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Having cleared the deck dive toward the sea to build up speed and translational lift and you were on your way.
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crash comic, yeah well don't believe everything that your read in a newspaper they say.
I must say I'm impressed with the advice to spin it up to 3400. How does that comply with the requirements of CAR 138. What dispensation did you have, it seems indicative of the pervasive cowboy nature of helicopter ops IMHO.
If I seem hard nose, let me explain. On a beautiful tropical morning we launched at 0600 with a flight of five Hueys to an airstrip some distance away to conduct combat assaults. I was tail end charlie (#5) and following refueling and shutting down at the strip, I was engaged in conversation with #4. He complained about certain problems with his aircraft and I volunteered to fly in his place, as the mission had only called for 4 aircraft, and I and my crew had been put on standby. He was adamant that he would fly the mission. I could very well have pulled rank and told him that I would fly in his place, but I respected his abilities, as we had been through some tough times together, and let him have his way.
While basking in the sunshine following their launch for the CA we saw the C & C aircraft come into POL, which was unusual as the flight usually landed well before C & C. C & C landed at POL and a figure could be seen walking down the airstrip towards us at the opposite end of the strip. I walked up the strip to meet him half way to find it was our CO in tears. #4 had crashed with the loss of all on board, 4 crew and 10+ pax. There was an official finding to the cause, but with my conversation with the AC prior to the flight I have a fair idea to the real cause, which is at complete odds with the official finding.
It is somewhat mind concentrating to stand along side a Huey, the top of which reaches your throat, the interior painted red rather than the military grey, and picking pieces of nomex containing flesh off bolt heads.
RIP guys, very few appreciate what we went through and did.
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it seems indicative of the pervasive cowboy nature of helicopter ops IMHO.
Yes there’s no doubt that there will be a certain cowboy attitude creep into – “high volume hours with not a great amount of hindsight experience situations”
I’m guessing that was the problem with the accident which you reported. What is it that you despair about? Not flying the mission yourself and sending the other A/C home, almost certainly still to an untimely end of flight even without its load, or the experience that you may have gained since which would tell you that an A/C which was developing an unexplained lateral or even vertical was an ironclad reason to ground it and send for the engineers?
We found that, and especially an increasing lateral when investigated would yield such unpleasant discoveries such as cracked masts. Now the rule is, - never fly with an increasing lateral. We have since found that blades on A/C which are difficult to track and inconsistent in the vertical plane also is reason to ground the aircraft. No doubt the catastrophic blade failure near Warragamba dam accident will refresh your memory there.
In our case we had studied the over speed engine and airframe check procedures and figured prior to this event that we were on safe ground. My event made us believe that we weren’t. In fact we figured later also that most of the power required to spin up to 3400 was used in doing just that, leaving little for the use of lifting. I even managed to prove that with the difference between 3300 and the red line of 3200. We were on the way to finding the most efficient blade RPM/engine power combination. It was not just a limitation imposed for the health of the engine. That is why we now teach as I stated before, to hold it at the red line and only load it to Max AUW as any a/c with an engine operating in specs will lift vertically its own Max AUW up to its hover OGE ceiling in free air, I.E. not close to trees .
Think about it, that is always a revelation to newbies straight from flight school, and many others and can be easily demonstrated.
If that is the case why on earth did the oz army adopt the cowboy attitude of fragrantly breaching CAR138 with their precious recommendation of exceeding the allowable RPM?
My referral to the crash comic is about an accident where the it stated that “the accident was caused by T/R failure”, when in fact both of the tail rotor blades had been torn off, and one of them flung at least 150 feet through light brush when they had contacted the ground. You would have to admit there is a major problem with that abhorrently fragrant “trial by media” supposition. Particularly, as the accident is still awaiting the pleasure of the coroners’ attention, for seven years now. It sounds to me that you are close to the ATSB action, perhaps if you’d like me to PM you the accident report number and you might look into it.
The beauty of these forums is that we can pass on gems to newbies.
They have been lucky to pick up a few from this one all of which relate to a single regulation, (CAR 138) that I’ll bet most have never been introduced to.
cheers tet
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Of course you may still lift "overweight" and not have any "Adverse Factors", for example use a technique that gets you airborne without exceeding the engine limitations. (for example a cusion creep at sea level on a cold, windy day in an open space and a very shallow climb out). Also consider this, even if you lift at the MGTOW, you can still simulate being over weight by climbing too quickly. ie rotor head pulls max weight upwards,(within limits) which dynamically adds weight during the climb.
So it makes me wonder, lift at MGTOW, climb out steeply within engine limitations, is probably a similar airframe stress to lifting at over MGTOW and make a lesser best rate of climb within engine limitations.
So it makes me wonder, lift at MGTOW, climb out steeply within engine limitations, is probably a similar airframe stress to lifting at over MGTOW and make a lesser best rate of climb within engine limitations.
In the late seventies the offshore oil industry used much the same rulers as routine civil air transport. Male passengers weighed 170lbs, female 140lbs. You would plan your flight taking on the max amount of fuel as possible depending on the pax and freight. The manifest would arrive with nineteen pax at 170 lbs each. After start nineteen overweight gorillas, each at least 200lbs, would tramp out to the aircraft. 19X30=570lbs overweight to start off with. A whole generation of Pumas and S61s did not seem to suffer.
Going further back. The only way to check the power settings of turbine powered Whirwinds and Wessex was to run them on a tie down base. Here the aircraft were strapped to the ground on a specially built pan that had steel retaining rods set in the concrete. Some of the coning angles that the main rotor achieved setting full power were tremendous and all the strain was taken up by the gearbox mountings. Again they did not seem to suffer.
Years ago I had to carry out a check on an engine that had had a compressor stall and had cooked the turbine. There was no tie down available so we had to use human weight. It still got airborne with everybody inside at full power.
The problem with being over weight is not so much getting airborne but in forward flight. The aircraft has a VNE for a certain weight, you go above that weight and you have no idea what the VNE for your new weight is. Your rotor head will know because of the stresses that are building up by you flying in excess of that unknown VNE. One occassion that I remember a certain pilot used to ignore things like MAUW and VNE, full power was his only datum. He unknowingly overtook his flight commander and then the truth came out. They replaced all the rotor heads on all the aircraft he had flown.
All pilots will at some time or the other get airborne overweight, either knowingly or otherwise. Grotesquely overweight you bring it back at a reduced speed so as to look after the head. As a small percentage of your permissable weight fly it at a reduced speed until it gets down to MAUW. and then just carry on. As a rule of thumb if by continuing your flight it is going to take less time to get your weight down than by turning back then carry on.
A lot of the weight limitations are certification issues. The S76, for example, started off at 10,000, grew to 10,300 and then to 10,800lbs. I do not recall any S76 falling out of the sky because they were too heavy. The 332L is limited to 8,600 Kg, that is so it can meet various performance criteria. Ferry flights are exceptions and so are USL operations were you can go to 9,100 kgs all day as long as you can jettison your load.
I can visualise the barrack room lawyers and holier than thou brigade banging their flight manuals but these things happen. It stood me in good stead for 44 years and 18,000 hrs.
Going further back. The only way to check the power settings of turbine powered Whirwinds and Wessex was to run them on a tie down base. Here the aircraft were strapped to the ground on a specially built pan that had steel retaining rods set in the concrete. Some of the coning angles that the main rotor achieved setting full power were tremendous and all the strain was taken up by the gearbox mountings. Again they did not seem to suffer.
Years ago I had to carry out a check on an engine that had had a compressor stall and had cooked the turbine. There was no tie down available so we had to use human weight. It still got airborne with everybody inside at full power.
The problem with being over weight is not so much getting airborne but in forward flight. The aircraft has a VNE for a certain weight, you go above that weight and you have no idea what the VNE for your new weight is. Your rotor head will know because of the stresses that are building up by you flying in excess of that unknown VNE. One occassion that I remember a certain pilot used to ignore things like MAUW and VNE, full power was his only datum. He unknowingly overtook his flight commander and then the truth came out. They replaced all the rotor heads on all the aircraft he had flown.
All pilots will at some time or the other get airborne overweight, either knowingly or otherwise. Grotesquely overweight you bring it back at a reduced speed so as to look after the head. As a small percentage of your permissable weight fly it at a reduced speed until it gets down to MAUW. and then just carry on. As a rule of thumb if by continuing your flight it is going to take less time to get your weight down than by turning back then carry on.
A lot of the weight limitations are certification issues. The S76, for example, started off at 10,000, grew to 10,300 and then to 10,800lbs. I do not recall any S76 falling out of the sky because they were too heavy. The 332L is limited to 8,600 Kg, that is so it can meet various performance criteria. Ferry flights are exceptions and so are USL operations were you can go to 9,100 kgs all day as long as you can jettison your load.
I can visualise the barrack room lawyers and holier than thou brigade banging their flight manuals but these things happen. It stood me in good stead for 44 years and 18,000 hrs.