%0 Conference Paper %B 75th Annual Conference, Denver, Colorado %D 2016 %T 3659. Weight and CG Curtailment %A Brown, Patrick %K 01. Aircraft Loading - General %K 17. Weight Engineering - Procedures %X Without fail, weight and center of gravity (CG) change during every aircraft flight. In some aircraft, especially large passenger aircraft, the ability to safely account for weight and CG movement during flight can become problematic. There are unknown passenger and cargo weights. The crew and passengers often move large distances in the cabin and the cargo CG can shift unexpectedly during flight. Angle of attack and fuel burn often create CG movements due to fuel migration. The complexity of the analysis is large and the risk of failure is enormous. Any one or combination of those events in flight can be catastrophic. However, the risk to crew, passengers, cargo and aircraft can be mitigated by the proper use of weight and CG curtailment. In fact, by applying proper weight and CG curtailment methods during flight planning, those risks can be entirely eliminated as a cause of incident, accident, or catastrophic failure. The only other possible way of eliminating those risks would be to know the weight and CG of every crewman, passenger, cargo, and gallon of fuel and completely limit their movement. Or, better yet, develop a ‘smart’ plane that senses CG movement and automatically compensates for it during flight. As yet, that technology does not exist, is too costly and or complex to implement in a commercial aircraft environment. Weight and CG curtailment uses quantitative methods to shrink the flight envelope so that every likely shift in weight and CG is accounted for in the given flight profile or mission. In fact, as the only viable solution, every large aircraft operator uses weight and CG curtailment in one form or another to dispatch their aircraft in a safe and timely manner. %B 75th Annual Conference, Denver, Colorado %I Society of Allied Weight Engineers, Inc. %C Denver, Colorado %P 10 %8 05/2016 %U https://www.sawe.org/papers/3659/buy %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE3659 %0 Conference Paper %B 67th Annual Conference, Seattle, Washington %D 2008 %T 3452. Queuing Analysis Methods for Decision Making %A Brown, Patrick %K 30. Miscellaneous %X The ability to make good and timely decisions is an essential skill for all Engineering Managers. Basing management decisions on tribal knowledge or ‘gut’ feelings is no longer acceptable. Where possible, the decision making process must be assisted via quantitative methods. There are a variety of complex quantitative methods for decision-making. A few examples are linear programming, non-linear programming, probability theory, multivariable optimization, multidisciplinary optimization, Pareto analysis, decision trees, and Monte Carlo simulation. As such, queuing theory (the topic of this paper) is a subset of probability theory. Specifically, queuing theory is the mathematical study of waiting lines (queues). The theory enables mathematical analysis of several related processes, including arriving at the (back of the) queue, waiting in the queue (essentially a storage process), and being served by the server(s) at the front of the queue. The theory permits the derivation and calculation of several performance measures including the average waiting time in the queue or the system, the expected number waiting or receiving service, and the probability of encountering the system in certain states such as empty, full, having an available server, or having to wait a certain time to be served (utilization). One can even derive the probability that a customer will exit the queue (balk). Queuing analysis is the direct application of queuing theory. Despite its complex origin, queuing analysis yields quick and accurate forecasts of resource needs based on nothing more than a working knowledge of flow and service rates. Queuing analysis can occur on single lines and multiple lines, both in parallel and in series. In manufacturing, the output of one queue is often the input for the next. %B 67th Annual Conference, Seattle, Washington %C Seattle, Washington %P 17 %8 5/19/2008 %U https://www.sawe.org/papers/3452/buy %9 30. Miscellaneous %M 3452 %L 30 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE3452 %0 Conference Paper %B 66th Annual Conference, Madrid, Spain %D 2007 %T 3434. Evaluation of Single Engine Weight and Center of Gravity Determination Methods %A Brown, Patrick %K 08. Weighing %X There is no greater task for a Weight Control Engineer than determining an aircraft?s weight and center of gravity (CG). Although the concept of balance or CG is easy to grasp, calculating or measuring it for complex objects, such as an aircraft, is very difficult. The accurate calculation of an aircraft?s CG is a primary factor in any flight operation. It directly affects aircraft safety, performance, and mission capability. This paper contains a comparative analysis of four potential methods for weight and CG measuring for single-engine aircraft. They are analytic, current, simplified weigh on wheels, and weigh on wheels, respectively. Each of the four methods is analyzed using historical data obtained from Cessna Aircraft Company. The methods are evaluated using statistical queuing and variation analysis. The queuing analysis, based on the Allen-Cunneen approximation model, assumes a normal probability distribution for both the arrival and service rates. It also considers only the known move rate of one product line. It does not consider either multiple lines or multiple move rates. However, it does consider both the capability and the productivity gains as a function of the weighing method selected. The variation analysis compares the results with the guidelines established in Advisory Circular (AC) 120-27E and its Cessna corollary, CSPS-011. These are 1.0% of the fleet weight and 0.5% of the mean aerodynamic cord. For the Cessna model considered in this investigation, these are +/-20.6 pounds (9.344 kg) and +/-0.29 inches (0.7366 cm), respectively. Probability plots contain the results obtained for each method. The plots also illustrate some interesting relationships between the measurements of weight and distance and the calculation of center of gravity (CG). %B 66th Annual Conference, Madrid, Spain %I Society of Allied Weight Engineers %C Madrid, Spain %P 48 %8 5/28/2007 %G eng %U https://www.sawe.org/papers/3434/buy %9 8. Weighing %M 3434 %1 Non-Member Price: $24.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 24 %4 SAWE3434 %0 Conference Paper %B 65th Annual Conference, Valencia, California %D 2006 %T 3397. Weight on Wheels: Software Development %A Kaufman, Johathan %A Brown, Patrick %K 08. Weighing %X The accurate and precise measurement of aircraft weight and center of gravity (CG) is a demanding task in the aviation industry. To that end, a group of Cessna employees was challenged by a member of its Senior Leadership Team (SLT) to improve the in-house weighing process. Through multiple initiatives, Cessna Aircraft Company has developed and patented the most accurate aircraft CG measurement system in the industry. In order for the system to work, Cessna engineers developed and copyrighted a sophisticated software package. The presentation will show how the team designed, developed, and implemented the Weight on Wheels (WoW) software package. The topics of ongoing and future software development will also be discussed. %B 65th Annual Conference, Valencia, California %I Society of Allied Weight Engineers %C Valencia, California %P 35 %8 5/20/2006 %G eng %U https://www.sawe.org/papers/3397/buy %9 8. WEIGHING %M 3397 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE3397 %0 Conference Paper %B 64th Annual Conference, Annapolis, Maryland %D 2005 %T 3369. Weigh on Wheels %A Brown, Patrick %K 08. Weighing %X This paper introduces a new paradigm to the aviation industry. The new paradigm is a method for weighing and calculating the center of gravity of an aircraft without leveling the aircraft. The solution requires the measurement and input of eight variables into a complex algorithm contained within a software program. The eight variables are: 1-3) the scale reactions at each of the wheel locations, 4-6) the measurement of each of the exposed oleo lengths, 7-8) the measurement of the angle of incidence of the pitch and roll axis to earth center. With an accelerometer installed at a tooled location, Cessna Engineers determined aircraft level repeatedly and accurately within 0.01 of a degree of earth center. The ability to measure aircraft level further enabled Cessna Engineers to improve the calculation of aircraft C.G. by 14 Sigma! Because of moving from weighing and leveling aircraft on jacks with load cells to Weigh on Wheels, Cessna can claim a 33% reduction in labor for the first aircraft weighing. Cessna can also claim a 40% reduction in labor for the first and second successive aircraft weighings. Finally, Cessna can claim up to a 68% reduction in labor for the first and second weighings and a reweigh. Not only can Cessna claim increased labor efficiency as a direct result of the accuracy of Weigh on Wheels, but they can also claim a reduction in the total number of weighings performed. Statistically, Cessna weighs each aircraft 2.78 times. With Weigh on Wheels, Cessna can now claim that each aircraft is weighed an average of 2.16 times. Entitlement is 2.0 weighings per aircraft. With the reduced number of weighings per aircraft and the reduction in time required to weigh an aircraft, Cessna was able to replace 12 sets of jack scales with 3 portable sets of platform scales! Finally, Weigh on Wheels is a much safer method of weighing aircraft. It is safer for the aircraft. It is safer for the mechanics. While no documented cases of injury exist as a direct result of weighing an aircraft, wing panels cost in the tens of thousands of dollars. %B 64th Annual Conference, Annapolis, Maryland %I Society of Allied Weight Engineers, Inc. %C Annapolis, Maryland %P 23 %8 5/14/05 %G eng %U https://www.sawe.org/papers/3369/buy %9 8. WEIGHING %M 3369 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE3369 %0 Conference Paper %B 60th Annual Conference, Arlington, Texas, May 19-23 %D 2001 %T 3126. The General Aviation Revitalization Act Causes and Consequences %A Brown, Patrick %A Gregg, Karla %K 30. Miscellaneous %X

This paper completes a detailed analysis of the General Aviation Revitalization Act (GARA) of 1994. As a precursor to the analysis, the authors provide a brief history of the industry. The history describes the state of the industry leading up to its peak in 1978 and then its precipitous decline by 1993. The staggering economic decline gave the federal government the motivation to enact GARA. The analysis of GARA pays special attention to the legal implications as well as the arguments, both pro and con, for its enactment. Example illustrations show GARA's impact on the Weights Engineer. Finally, the analysis describes GARA's influence on the overall general aviation manufacturing industry and economy.

%B 60th Annual Conference, Arlington, Texas, May 19-23 %I Society of Allied Weight Engineers, Inc. %C Arlington, Texas %P 27 %8 5/19/01 %G eng %U https://www.sawe.org/papers/3126/buy %9 30. MISCELLANEOUS %M 3126 %1

Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free.

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