I always make sure that my W&B is within limits on paper :)
The DA40 I fly is limited to 1150 MTOW. We have the stronger engine (2.0S), but the POH has not been updated. I prefer to depart a bit overweighted rather than low on fuel. You need to know your aircraft though.
The airliners are weighed – just not before every flight. That gives you the Basic, or Dry Operating Weight. Weight by luggage number is a thing of the past – all bags either container or bulk are weighed. Cargo as well. The only variable is the difference between real and nominal passenger weight.
Some aircraft “weighing kits” were installed on some aircraft – specifically on the oleos. However a harder landing or any inclination on the apron would throw the measurement off as the oleos wouldn’t all extend equally so the kits were discontinued as not really useful. Also when loading up you want to be able to know and plan your load before it actually gets on…
Countless grossly overweight AOC departures – I wouldn’t think so. No dispatcher in his/her right mind would fudge figures to that extent – not for the 20 quid an hour they get. Remember, if the plane crashes at the end of the runway, whoever signed the loadsheet is the first dude in the line of fire.
Now use of derated thrust combined with a mistype of say 100tons in gross weight entry – maybe Chris can comment more on the technicalities of that- yeah that happens and the result will be very impressive. But countless grossly overweight line ops I don’t think so – unless it’s a Russian crew doing their own W&B and it’s only their a$$ on the line, “Vodka Burner” style.
I know a number of airline pilots and they say airliners are not weighed. The W&B is calculated only, using a nominal passenger and luggage number. Their opinion is that they probably are overweight a lot of the time but it doesn’t matter because all the airports they fly to have much longer runways than is needed. The AOC margins for jets are massive.
I was surprised to hear there is no weight indication. In the 1980s I worked on a project which displayed the weight of a lorry, measured with strain gauges on the suspension. It would be straightforward to do this on aircraft landing gear because there are obvious points for attaching the sensors.
There are countless stories of obviously grossly overweight AOC departures. One A340 out of Gatwick was still at 1000ft AGL some 20 miles out (in Class G) – some years ago. There was some trouble over that. One guy I have flown with, a retired B747 flight engineer, has a scary (totally illegal flying, UK airline) story for every day of the year. So they seem to manage it, despite the passengers being only a small % of the MTOW. Or at least they used to; maybe the practices have been tightened in recent years.
It is worth knowing basics like if you are 1% heavier you need 2% more runway, a 1% runway gradient in your favour is worth x knots of tailwind, etc, and these rules don’t stop working just because you are 10% over MTOW. Sure the ASI markings are out of the window once you are over MTOW…
blueline wrote:
Absolutely. It is widely known that aviation suffers from an appealing lack of regulation, certification and bureaucracy
You’re right 
A lot of that has to do with overregulation and “arse” covering, however the MTOW limits in the POH are based on safety calculations that have a defined (and agreed) safety margin, and this limit results in the aircraft performing as presented in the POH (at least at certification time).
Most of the limits on the Airspeed indicator are derived from the MTOW. The structural design of the aircraft is based on MTOW, the maneuvring limits (g-limits) are based on MTOW etc. etc. etc. etc.
I would have thought it is a no-brainer to adhere to the MTOW as stated in the POH, because you lose a lot of layers of protection of you decide to go above and you are basically a test pilot.
But apparently a lot of people don’t take the rules so literally… and a lot of the argumentation comes down from one of the hazardous attitudes (anti-authority, invulnerability, macho).
I’m not saying W&B is an exact science, but it is easily possible to get is pretty much dead on, if you put a little effort into it. And if you can say “No” to your passengers if the payload turns out to be to great (another interesting personality trait…)
Regarding the statement “airlines always fly overweight”. May I point out that an A380’s MTOW is 575,000 kgs, whereas the 853 pax it could carry weigh perhaps 65,681 kgs i.e. only 11% of the aircraft weight. In a typical C172, the payload makes easily 30% of the MTOW. One person weighing heavier on an A380 will change nothing, and there will be some lighter people too like asians etc. But in a C172 it changes everything.
There’s more than one club/flying school nearby where the appearance of the CFI made me wonder if the C152’s aren’t overweight even without a pupil on board…
And yes, a PA28 does better but as a fourseater that is a peer to the C172 not to the C152.
It’s probably accurate to say that a C150 with two big blokes will be over max but a PA28 with the two should be ok.
OTOH a lot of flight training is done with little fuel because they are not going far.
My PPL training certainly involved a lot of scarily low fuel but I went along with it IF an instructor was present on the plan that if we ran out I would fold up my arms and leave him holding the baby. When I flew solo I used to fill up and got some bollocking for it.
Time for the regulator to step in…
Absolutely. It is widely known that aviation suffers from an appealing lack of regulation, certification and bureaucracy 
…
achimha wrote:
Your level of surprise shows me that I should not take your previous statements too serious…
I guess I’ve only attended good flight schools then! Time for the regulator to step in…
Michael wrote:
I have seen many mistakes in “Computated” W&B sheets since there are so many equipment options that may be installed or removed by either the Factory, the Dealer or any other entity that happens to work on it.
I’ve seen aircraft reweighed after equipment had been removed or installed, with a new weigh report produced. There’s probably regulations for engineers for when that is required.
Archie wrote:
Not sure what you’re talking about here. Are you stating it’s regularly done by flightschools and they get away with it time and time again?
Your level of surprise shows me that I should not take your previous statements too serious…
