CH-AERO · REGULATORY COMPLIANCE
Official Requirements For Aircraft Weighing
This page sets out the regulatory framework within which CH-Aero operates, sourced from four aviation authorities. Every regulatory statement is a direct quotation, where CH-Aero's position is stated.
How CH-Aero Fits Within the Regulatory Framework.
CH-Aero performs aircraft weighing as a subcontractor operating under the Part-145 approval of the contracting MRO. The MRO's maintenance organisation approval covers the activity; CH-Aero operates within the documented procedures of that organisation.
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The regulations on this page define what is required of weighing equipment, who may perform the weighing, how often aircraft must be weighed, and what accuracy is required. CH-Aero's calibration certificate and signed W&B report, delivered with every weighing, are the documentary evidence of compliance with those requirements.
CH-AERO · REGULATORY COMPLIANCE
Table 1 - Accuracy criteria for weighing equipment
Source: EASA AMC1 CAT.POL.MAB.100(b), ED Decision 2014/015/R · Adopted verbatim by UK CAA, ORS9 Decision No. 1 · The only published regulatory accuracy table for aircraft weighing equipment from a major aviation authority.
SCALE OR CELL LOAD
TYPICAL AIRCRAFT CATEGORY
REQUIRED ACCURACY
Below 2,000 KG
Light aircraft / GA
± 1%
2,000 KG to 20,000 KG
Regional/ turboprop
± 20 KG
Above 20,000 KG
Commercial aircraft (Narrow-body, whide-body)
± 0,1%
The accuracy criteria in Table 1 apply per scale or cell load at the point of weighing, not by aircraft type. CH-Aero weighs all aircraft categories and meets the accuracy requirement applicable to the corresponding scale/cell load band under Table 1, confirmed by calibration certificate on every deployment.
Regulation (EU) No 965/2012 · Air Operations · ED Decision 2014/015/R · Easy Access Rules for Air Operations, Revision 24 (March 2026)
CAT.POL.MAB.100(b) · Mass and balance, loading · Binding implementing rule · Regulation (EU) No 965/2012
1.
"The weighing shall be accomplished by the manufacturer of the aircraft or by an approved maintenance organisation."
CH-Aero performs aircraft weighing as a subcontractor under the Part-145 approval of the contracting MRO. The MRO is the approved maintenance organisation within the meaning of this article.
CAT.POL.MAB.100(b) · Mass and balance, loading · Binding implementing rule · Regulation (EU) No 965/2012
"The operator shall establish the mass and the CG of any aircraft by actual weighing prior to initial entry into service and thereafter at intervals of four years if individual aircraft masses are used. The accumulated effects of modifications and repairs on the mass and balance shall be accounted for and properly documented. Aircraft shall be reweighed if the effect of modifications on the mass and balance is not accurately known."
2.
CH-Aero performs the actual weighing that establishes mass and CG for the operator's 4-year (individual) cycle. The last sentence of this article, reweighing where the effect of a modification is not accurately known, is the EASA equivalent of DGCA §4.3 below; CH-Aero's weighing service is what operators call on to satisfy it.
AMC1 CAT.POL.MAB.100(b) · Mass and balance, loading · Section (b) · ED Decision 2014/015/R
"The mass and centre of gravity (CG) position of an aircraft should be revised whenever the cumulative changes to the dry operating mass exceed ±0.5 % of the maximum landing mass or, for aeroplanes, the cumulative change in CG position exceeds 0.5 % of the mean aerodynamic chord. This may be done by weighing the aircraft or by calculation."
3.
This is the operative threshold behind the "reweighed if the effect of modifications is not accurately known" clause in CAT.POL.MAB.100(b) above. CH-Aero's weighing is the means by which the operator resets the mass and CG once this threshold is reached, rather than relying on calculation alone.
AMC1 CAT.POL.MAB.100(b) · Mass and balance, loading · Section (d) · ED Decision 2014/015/R · Easy Access Rules for Air Operations, Revision 24 (March 2026)
"Any equipment used for weighing should be properly calibrated, zeroed, and used in accordance with the manufacturer's instructions. Each scale should be calibrated either by the manufacturer, by a civil department of weights and measures or by an appropriately authorised organisation within two years or within a time period defined by the manufacturer of the weighing equipment, whichever is less. The equipment should enable the mass of the aircraft to be established accurately. One single accuracy criterion for weighing equipment cannot be given. However, the weighing accuracy is considered satisfactory if the accuracy criteria in Table 1 are met by the individual scales/cells of the weighing equipment used."
4.
CH-Aero's AW5 platform scales are calibrated within 0.1% accuracy, in accordance with and within the guidelines set out in AMC1 CAT.POL.MAB.100(b) and its Table 1 accuracy criteria. Calibration is performed annually by the manufacturer, inside the two-year maximum this AMC allows, and the calibration certificate accompanying every deployment is the documentary record of that compliance.
Regulation (EU) No 1321/2014 · Annex II (Part-145) · Section A · 145.A.75 Privileges of the organisation · Easy Access Rules for Continuing Airworthiness
5.
"Arrange for the maintenance of any aircraft or component for which it is approved at another subcontracted organisation that works under the management system of the organisation. This is limited to the work permitted under the procedures established in accordance with point 145.A.65 and it must not include a base maintenance check of an aircraft, or a complete workshop maintenance check or overhaul of an engine or an engine module."
CH-Aero performs aircraft weighing as a specialist subcontractor to a Part-145 approved maintenance organisation (MRO). Under point 145.A.75(b), a Part-145 organisation may subcontract specific maintenance activities, provided these are carried out under its management system and in accordance with the procedures established under point 145.A.65. The Part-145 organisation remains responsible for the maintenance performed under its approval.
ORS9 Decision No. 1 · Retained Air Operations regulation · regulatorylibrary.caa.co.uk
CAT.POL.MAB.100 · Mass and balance, loading · ORS9 Decision No. 1
1.
"The weighing shall be accomplished by the manufacturer of the aircraft or by an approved maintenance organisation."
CH-Aero performs aircraft weighing as a subcontractor under the Part-145 approval of the contracting MRO. The MRO is the approved maintenance organisation within the meaning of this article.
CAT.POL.MAB.100(b) · Mass and balance, loading · Binding implementing rule · Regulation (EU) No 965/2012
"The operator shall establish the mass and the CG of any aircraft by actual weighing prior to initial entry into service and thereafter at intervals of four years if individual aircraft masses are used, or nine years if fleet masses are used. The accumulated effects of modifications and repairs on the mass and balance shall be accounted for and properly documented. Aircraft shall be reweighed if the effect of modifications on the mass and balance is not accurately known."
2.
CH-Aero performs the actual weighing that establishes mass and CG for UK operators on the same 4-year (individual) or 9-year (fleet) cycle as EASA. The reweighing-after-modification clause is the UK equivalent of DGCA §4.3 below.
AMC1 CAT.POL.MAB.100(b) · Mass and balance, loading · Section (b) · ORS9 Decision No. 1
"The mass and centre of gravity (CG) position of an aircraft should be revised whenever the cumulative changes to the dry operating mass exceed ±0.5 % of the maximum landing mass or, for aeroplanes, the cumulative change in CG position exceeds 0.5 % of the mean aerodynamic chord. This may be done by weighing the aircraft or by calculation."
3.
Identical to the EASA threshold. CH-Aero's weighing is the means by which a UK operator resets mass and CG once this threshold is reached.
AMC1 CAT.POL.MAB.100(b) · Mass and balance, loading · Section (d) + Table 1 · ORS9 Decision No. 1
"Any equipment used for weighing should be properly calibrated, zeroed, and used in accordance with the manufacturer's instructions. Each scale should be calibrated either by the manufacturer, by a civil department of weights and measures or by an appropriately authorised organisation within two years or within a time period defined by the manufacturer of the weighing equipment, whichever is less. The equipment should enable the mass of the aircraft to be established accurately. One single accuracy criterion for weighing equipment cannot be given. However, the weighing accuracy is considered satisfactory if the accuracy criteria in Table 1 are met by the individual scales/cells of the weighing equipment used."
4.
The CAA's regulatory library provides Table 1 in plain HTML, the most directly accessible rendering of the accuracy criteria per scale/cell load band.
CH-Aero's AW5 platform scales are calibrated annually by the manufacturer, inside the two-year maximum, and the calibration certificate accompanying every deployment is the documentary record of compliance with this AMC.
Regulation (EU) No 1321/2014, retained as UK law · Annex II (Part-145) · Section A · 145.A.75 Privileges of the organisation · CAA Regulatory Library
"Arrange for the maintenance of any aircraft or component for which it is approved at another subcontracted organisation that works under the management system of the organisation. This is limited to the work permitted under the procedures established in accordance with point 145.A.65 and it must not include a base maintenance check of an aircraft, or a complete workshop maintenance check or overhaul of an engine or an engine module."
5.
Retained identically from Regulation (EU) No 1321/2014. This is the basis on which CH-Aero performs weighing as a subcontractor to a UK Part-145 MRO, and it is what satisfies "approved maintenance organisation" in CAT.POL.MAB.100(c) above. As under EASA, the privilege is conditional on the MRO's MOE documenting CH-Aero under its 145.A.65 subcontractor-control procedure, CH-Aero does not hold it independently.
Advisory Circular AC 120-27F · Aircraft Weight and Balance Control · Published 6 May 2019
AC 120-27F · Chapter 2, §2.1.4.1 · Individual Aircraft Weighing Program
1.
"Aircraft are normally weighed at intervals of 36 calendar-months. An operator may extend this weighing period for a particular model aircraft when pertinent records of actual routine weighing during the preceding period of operation show that W&B records accurately reflect aircraft weights and CG positions are within the cumulative limits specified for establishment of BEW. Under an individual aircraft weighing program, an increase should not be granted that would permit any aircraft to exceed 48 calendar-months since its last weighing."
CH-Aero's periodic weighings are what allow an operator to build the "pertinent records of actual routine weighing" this article requires before an extension beyond 36 months can be granted, up to the 48-month ceiling.
AC 120-27F · Chapter 2, §2.1.4.3 · Weighing Aircraft-Modifications
2.
"For most aircraft modifications, a mathematical calculation of the W&B change is practical. For some modifications, such as interior reconfigurations, the large number of parts removed, replaced, and installed may make an accurate determination of the W&B change by computation impractical."
This is the FAA equivalent of DGCA §4.3 below, reweighing after a modification where the calculated weight change cannot be relied on. §2.1.4.3.2 confirms an operator "may choose not to calculate the weight change but to reestablish the aircraft W&B by reweighing the aircraft prior to subsequent revenue operation." CH-Aero's weighing service is what an operator uses to satisfy this when it chooses, or is required, to reweigh rather than calculate.
AC 120-27F · Chapter 2, §2.1.5.2 · Procedures for weighing an aircraft
3.
"The operator should ensure that all scales are certified and calibrated by the manufacturer or a certified laboratory, such as a civil department of weights and measures, or the operator may calibrate the scale under an approved calibration program. The operator should also ensure that the scale is calibrated within the manufacturer's recommended time, or time periods, as specified in the operator's approved calibration program."
AC 120-27F does not publish a specific accuracy percentage for external weighing scales. The requirement is calibration by the manufacturer or a certified laboratory, within the manufacturer's recommended interval.
CH-Aero's AW5 platform scales are calibrated annually by the manufacturer, and a calibration certificate is provided on every deployment, the documentary record an operator needs to demonstrate compliance with this paragraph.
CAR Section 2 - Airworthiness, Series X Part II · Revision 9, 17 January 2023 · Signed: Arun Kumar, Director General of Civil Aviation
CAR Section 2, Series X Part II · §4.2 · Page 2
1.
"Aircraft weighing more than 2000 kg. shall be re-weighed every five years unless it is required to be re-weighed in accordance with para 4.3 of this CAR."
CH-Aero performs the weighing that resets this 5-year cycle for operators of aircraft above 2,000 kg operating in India.
CAR Section 2, Series X Part II · §4.3 · Page 2
2.
"An aircraft shall be required to be reweighed if it has undergone major repair, or major alteration or there has been major change in the interior arrangement of pilot/pax/cargo compartments which affect already determined weight and balance data and which cannot be accurately computed without fresh weighment."
CH-Aero's on-platform weighing is the new weighment this article requires when a repair, alteration, or interior change makes the existing W&B data unreliable and the change cannot be accurately computed instead.
CAR Section 2, Series X Part II · §4.3 · Page 2
3.
"The renewal of the Certificate of Airworthiness of an aircraft shall be subjected to following of the requirements of para 4."
Para 4 of this CAR covers the complete weighing schedule, including §4.2 (5-year cycle) and §4.3 (post-repair reweighing). Compliance with these requirements is a condition for Certificate of Airworthiness renewal. CH-Aero's weighment record and signed weight schedule are the evidence an operator submits to show para 4 has been followed, making CH-Aero's work a precondition to CoA renewal for aircraft that fall due for reweighing under §4.2 or §4.3.
CAR Section 2, Series X Part II · §5 · Page 3
4.
"After the aircraft has been weighed as required, the following persons shall prepare the weight Schedule: (i) A person specifically approved by DGCA for the purpose in any organization. OR (ii) A person specifically approved by Quality Manager in an organization approved under CAR 145 provided procedure for grant of such approval is documented in Maintenance Organization Exposition."
This is the DGCA equivalent of EASA's 145.A.75(b): it is limb (ii) that CH-Aero relies on. CH-Aero's weighing must be carried out by a person specifically approved by the Quality Manager of the India partner's CAR-145-approved organisation (Field International), with that approval procedure documented in Field International's Maintenance Organisation Exposition, not by DGCA approving CH-Aero directly.
CAR Section 2, Series X Part II · §7 · Page 3
5.
"The Regional/Sub-regional Airworthiness office shall be intimated in advance about the weighing of the aircraft who may associate with the weighing process. The weighing of the aircraft shall be done in supervision of the Quality Manager or his representative, who shall be responsible for following the documented procedures of weighment. The duly signed weight schedule shall be submitted to Regional/Sub-Regional Airworthiness Office along with the computation details and weighment printout if available. After scrutiny the weight schedule shall be approved by Regional Airworthiness Office."
This article requires supervision by the CAR-145 organisation's Quality Manager or representative, not by CH-Aero itself, and advance notice to the Regional/Sub-Regional Airworthiness Office. CH-Aero's weighing must be scheduled and conducted within this supervisory structure for the resulting weight schedule to be submissible for DGCA approval.
CAR Section 2, Series X Part II · §11.2 · Page 5
6.
"The weighing scales used for the purpose of weighment of aircraft shall be calibrated at specified intervals. This requirement may be reflected in the Maintenance Organisation Exposition."
§11.2 applies specifically to aircraft weighing scales. §11.1 (same page) covers passenger baggage scales separately. DGCA does not prescribe a specific accuracy percentage in this CAR; the calibration interval and accuracy standard are defined in the operator's MOE. CH-Aero's AW5 scales are calibrated annually by the manufacturer, with a calibration certificate provided on every deployment. The India partner's MOE is where this interval should be formally reflected to satisfy this article.