It is important to know the weight of an aircraft for maintaining safe flight operations throughout its operational life. FAA certifies each aircraft type and before leaving the factory for delivery the aircraft gets weighed and weight and balance report is generated and delivered with the aircraft. The weight and balance report specifies the empty weight of the aircraft and determines the center of gravity at which the aircraft balances.
Almost all aircraft tend to gain weight over time. This can happen due to the aircraft being repainted without removing old paint. It can also be due to the accumulation of grime, oil, and grease in areas of the aircraft that are not easily accessible for cleaning. Aircraft modifications such as improving avionics on the cockpit to seat configurations in the cabin can change the aircraft’s weight by several hundred pounds. Although these weights are calculated, it is best to weigh them again after a fixed period or after a major change in its configuration.
FAA does not require the aircraft to be weighed routinely. However, there is an FAA requirement that the airplane always has a current and accurate weight and balance report. It is a good practice to periodically weigh the aircraft on scales and confirm its actual empty weight and center of gravity. Normally airlines weigh their large commercial planes roughly every four years.
Platform scales are most commonly used to weigh aircraft. Platforms are available in a variety of sizes and weight ranges. To weigh the aircraft it can be moved or lowered onto the platform scales during regular maintenance. The weighing platforms are quite easy to use and offer a good choice for the maintenance shops that do not have jacks for many different types of aircraft. The main limits in these weighing platforms are the tire size and the weight range. Some aircraft are too large to fit on a weighing platform. Of course, it is essential to use the right size scale and platform for each aircraft type.
The platform scale is placed on the hangar floor in a level condition. Ramps and a tug are used to position the airplane tire on top of the platform and centered. There are electronic load cells embedded in the platform that sense the weight and they generate an electrical signal corresponding to the weight. There is an electronic strain gauge in the load cell that measures a proportional change in electrical signal depending on the weight being sensed. A cable or wireless signal sends the data to the processor unit or a computer, which calculates the total weight of the aircraft and displays it on a digital readout panel or an LCD panel.
Platform scale or ramp wheel scale is designed and manufactured to be in a low profile, which is easy to handle, safe, accurate, and easy to use. The aircraft is pushed or towed on these scales which remain at ground level. Each scale can measure up to a load of 60,000 pounds, which is quite sufficient to weigh in the largest of aircraft. Platform scales are designed to weigh such large aircraft, and the scales send the weight readings to remote computers which calculate the total weight of the aircraft.
Before weighing, the aircraft must be drained of all fuel and onboard water. Even accumulated rainwater can add to the weight and produce an incorrect reading, so you should make sure that the plane is completely dry and empty of anything that could result in an incorrect reading.
The aircraft can be placed on the weighing platforms either by pushing onto the platform or by being jacked up and lowering it onto the platform during regular maintenance.
Of course, the platform needs to be the right size for the aircraft. Some large planes have very large tires, so the right scale size and platform choice are important. The capacity of the platform scale also needs to be considered. For most commercial aircraft, each scale is capable of weighing up to 60,000lb.
Even large aircraft do not require a heavy-duty scale. Since large aircraft have many more wheels which spread the weight over the surface evenly. The largest commercial passenger aircraft the Airbus A380 has 22 wheels which spread its weight quite evenly and each wheel does not have a very large load.
Since it is important to know the weight of the aircraft accurately the platform scales used to weigh them must be accurate. They have to be checked periodically for accuracy. The maximum period between calibration checks is one year. However, this period may be changed depending on the condition of the scales and their usage.
e2b calibration can calibrate your aircraft platform scales to industry standards as we are an ISO 17025: 2017 accredited facility. Our services are unmatched in the industry. e2b calibration can also provide on-site services. Please contact us for more information.