Weighing Of Aircraft | Aircraft Weighing | Lecture 06

Summary

This video script explains the process of weighing airplanes, detailing the necessary steps and equipment involved. It covers the pre-weighing checks, including verifying the completeness of the airplane and the calibration of weighing equipment. The methods for weighing light and large airplanes are outlined, such as using weighbridge scales for smaller planes and hydrostatic units or strain gauges for larger ones. A simple weighing schedule for a light airplane is demonstrated, followed by a more complex example for a large airplane. The script also discusses calculating the center of gravity and the documentation process for weighing.

Takeaways

• 😀 Airplanes are initially weighed by the manufacturer or an approved maintenance organization.
• 😀 Prior to weighing, the airplane must be checked to ensure all equipment is complete and fluids are accounted for.
• 😀 The airplane must be clean and weighed in a fully enclosed, draft-proof building with air conditioning turned off.
• 😀 The equipment used for weighing must be calibrated and zeroed according to the manufacturer’s instructions.
• 😀 Scales must be calibrated by authorized organizations at regular intervals, typically every two years.
• 😀 Fleet values are determined by weighing a certain number of airplanes within a specified evaluation period.
• 😀 There are specific regulations (e.g., EU ops) detailing the number of airplanes that need to be weighed to establish fleet values.
• 😀 Light airplanes are typically weighed using a weighbridge scale, with separate platforms under each wheel assembly.
• 😀 Larger airplanes are weighed using hydrostatic units or electronic strain gauges to measure load and mass accurately.
• 😀 A simple weighing schedule involves recording mass readings at each wheel, calculating moments, and determining the center of gravity.
• 😀 The final weighing schedule must be signed, dated, and retained in the airplane’s technical log until the next weighing.

Q & A

What is the first step in weighing an airplane?

The first step in weighing an airplane is to check that all the airplane equipment is complete and that all fluids are accounted for before the weighing process begins.

Why is it important to weigh the airplane in a fully enclosed, draft-proof building?

It is important to weigh the airplane in a fully enclosed, draft-proof building to ensure accurate results, as external drafts or wind can affect the scale readings.

What must be done to the equipment used for weighing airplanes?

The equipment used for weighing airplanes must be calibrated and zeroed according to the manufacturer's instructions. It must also be calibrated at regular intervals, typically every two years, or as specified by the manufacturer.

What is the role of fleet values in weighing airplanes?

Fleet values are used to estimate the mass of airplanes in a fleet by weighing a certain number of airplanes over a specific period (not exceeding 48 months), following a set of regulations outlined in EU OPS.

How do you determine the number of airplanes to be weighed for fleet values?

The number of airplanes to be weighed is determined based on a table provided in EU OPS 1. The table correlates the number of airplanes in the fleet with the minimum number of weighings required to establish fleet values.

What types of scales are used for weighing airplanes?

For light airplanes, weighbridge scales are typically used, where individual scales are placed under each wheel. Larger airplanes may require hydrostatic units or electronic strain gauges to measure mass.

What is the function of hydrostatic units in weighing large airplanes?

Hydrostatic units consist of a closed hydraulic cylinder placed between a lifting jack and a jacking point. The pressure generated in the cylinder is proportional to the load applied, which helps to register the airplane's mass.

What does the weighing process for a light airplane involve?

For a light airplane, the weighing process involves placing the airplane on weighbridge scales, recording the mass at each wheel, calculating the moments based on the mass and arm, and then determining the basic center of gravity.

How is the center of gravity of the airplane determined from the weighing data?

The center of gravity is calculated by dividing the total moment (sum of mass multiplied by arm) by the total mass of the airplane. This gives the location of the center of gravity relative to the datum point.

What information is included in a large airplane weighing report?

A large airplane weighing report typically includes two sets of readings, a net mass, and the necessary adjustments to arrive at the final total mass. The report is signed by the responsible engineer.