minitour said:
Do any of you use the "standard FAA male/female/bag" weights whenflying something light like a 172 or do you use actual weights? And if you used the "standard" weights, would he still violate you?
You have happened to stumble upon one of my pet peeves. (Caution: Lead Sled is climbing up on his soap box.
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You need to remember that the FAA's "Prime Directive" is that the ultimate responsibility for the flight resides with the PIC. Personally, I check the weight and balance numbers on the aircraft I fly. If there's ever an accident or serious incident, the weight and balance will be scrutinized as part of the investigation. For your own peace of mind - after all, it will be your license - you owe it to yourself to make sure that you are using correct numbers.
Typically 121 operations are allowed to use "standard" passenger weights. These weights will be reasonably accurate when averaged out over a passenger count that could be as high as a few hundred people. Also, to be say a couple of thousand pounds off, one way or another on a 300,000 pound airplane isn't as significant as being 300 pounds off on a 1600 pound Cessna. The FAA standard passenger weights were recently revised upward. Most part 135 operators aren't allowed to use standard weights.Aircraft the are operated under Part 135 must be reweighed every couple of years. Weighing an aircraft isn't a big deal and calculating the aircraft's center of gravity doesn't require a doctorate in mathematics.
Whats the big deal over weight and center of gravity issues? I'll explain it in relation to the business jets that I fly, but it also relates directly with larger airline equipment and smaller general aviation aircraft...
There are several weight and balance issues that pilots must address prior to each and every flight in jet aircraft. There are several “maximum weights” that have to be dealt with. For example, the Maximum Ramp Weight is the maximum weight that the aircraft is allowed to weigh sitting on the ramp loaded with fuel, passengers, baggage, crew, etc. There is the Maximum Takeoff Weight which reflects the maximum weight that the airplane can weigh at takeoff; the Maximum Landing Weight which is as the name implies, the maximum weight at which the airplane can be landed. (There are some other “maximum” weights, but these aren’t germane to this discussion.)
There are many reasons why aircraft engineers and designers establish these various weight limitations – some are structural in nature, others are performance related. The same concept applies to the aircraft’s center of gravity (CG) or balance point. There are prescribed limits to the range of locations along which the aircraft’s center of gravity or balance point may fall. Again, these limits exist for structural, performance and/or handling reasons.
As far as the various weight and CG limits go, they are out of the aircraft operator’s control. They are established by factory aeronautical engineers and aircraft designers, verified by factory and FAA test pilots, and approved and certified by both the factory and the FAA.
While these weights are listed as “maximum” weights, it does not mean that pilots are free to operate their aircraft at these specific maximum weights. Typically, pilots are required to operate the aircraft at a lower weight for any one of several reasons. FAA regulations require that transport category aircraft, be they airliners or bizjets, be operated at a weight and with a center of gravity location that will allow it to achieve a certain minimum level of performance in the event of an engine failure during takeoff. (You guys flying light twins have no such performance requirement and your aircraft typically have very poor to nonexistant single engine performance.) The required performance level varies upon the terrain and obstacles surrounding the airport. However, the basic requirement is this: In the event of an engine failure during takeoff, the aircraft must be able to either (1) stop on the remaining runway; or (2) continue the takeoff and clear all terrain and charted obstacles on the assigned flight path by a designated vertical distance. In other words, if an engine fails on takeoff, the aircraft must either be able to stop on the remaining runway or be light enough to continue the takeoff on the remaining engine and be able to climb to a safe altitude and return to an airport for landing – a guaranteed safe takeoff if you will.
The manufacturer of each transport category aircraft is required to furnish, and the crew is required to use, factory certified, FAA approved performance charts and/or other data that allows them to determine the maximum weight that each airplane can weigh for each combination of airport altitude, outside air temperature, runway length, runway slope, etc. These charts, as can be imagined, can be pretty complex; never the less, pilots are under a federally mandated legal obligation to calculate the aircraft takeoff performance and to operate the aircraft accordingly.
OK, now back to light single engine aircraft operations...
We've all seen guy who will load up their friends and family in their trusty Cessna 172 and blast off into the wild blue yonder without even bothering to check the weight and balance. They usually always performed a reasonably good walk around inspection of the aircraft - but that's as far as it went. Look up the duties of the PIC in the FARs and you'll see why just performing a walk around isn't enough. How many times have you seen a couple of lard a$$es get out of a Cessna 152?
Those who operate under parts 121 and/or 135 have different obligations, and in may cases a lot of help when it come to complying with their weight and balance requirements. I can only assume that most airline captains have never had to calculate the weight and balance of one of his typical passenger flights in their Boeing or Airbus. That doesn't mean that there isn't some one at his company who hasn't looked at each and every flight prior to issuing the dispatch release. 135 pilots have to fill out a two-part weight and balance document prior to each and every takeoff. One copy is carried on board the airplane and goes into a file at the completion of the flight. The other copy is either left with the FBO, etc. or faxed back to base. Us non-commercial guys flying light aircraft and bizjets under Part 91 have to fend for ourselves. Many times, the pilots of these aircraft just simply don't bother to do it. After all, "It's never killed me before." In general aviation, complaciency is one of the biggest killers.
'Sled
At that point, I made my way to run-up and was on my way. No bull story there, but I sweated all the way back home hoping that he didn't catch the tail #. A better though, just keep it undergross!
