Independent Part 66 and weight and balance update

My gut feeling is yes, P66 can do it.

__66.A.20 Privileges
Regulation (EU) 2021/700

(a) The following privileges shall apply:
1. A category A aircraft maintenance licence permits the holder to issue certificates of release to service following minor scheduled line maintenance and simple defect rectification within the limits of tasks specifically endorsed on the certification authorisation referred to in point 145.A.35 of Annex II (Part-145). The certification privileges shall be restricted to work that the licence holder has personally performed in the maintenance organisation that issued the certification authorisation.
2. A category B1 aircraft maintenance licence shall permit the holder to issue certificates of release to service and to act as B1 support staff following:
 maintenance performed on aircraft structure, powerplant and mechanical and electrical systems,
 work on avionic systems requiring only simple tests to prove their serviceability and not requiring troubleshooting.
Category B1 includes the corresponding A subcategory.
3. A category B2 aircraft maintenance licence shall permit the holder:
(i) to issue certificates of release to service and to act as B2 support staff for following:
 maintenance performed on avionic and electrical systems, and
 electrical and avionics tasks within powerplant and mechanical systems, requiring only simple tests to prove their serviceability; and
(ii) to issue certificates of release to service following minor scheduled line maintenance and simple defect rectification within the limits of tasks specifically endorsed on the certification authorisation referred to in point 145.A.35 of Annex II (Part-145). This certification privilege shall be restricted to work that the licence holder has personally performed in the maintenance organisation which issued the certification authorisation and limited to the ratings already endorsed in the B2 licence.
The category B2 licence does not include any A subcategory.
4. A category B2L aircraft maintenance licence shall permit the holder to issue certificates of release to service and to act as B2L support staff for the following:
 maintenance performed on electrical systems;
 maintenance performed on avionics systems within the limits of the system ratings specifically endorsed on the licence, and
 when holding the ‘airframe system’ rating, performance of electrical and avionics tasks within power plant and mechanical systems, requiring only simple tests to prove their serviceability.
5. A category B3 aircraft maintenance licence shall permit the holder to issue certificates of release to service and to act as B3 support staff for the following:
 maintenance performed on aeroplane structure, power plant and mechanical and electrical systems; and
 work on avionics systems requiring only simple tests to prove their serviceability and not requiring troubleshooting.
6. A category L aircraft maintenance licence shall permit the holder to issue certificates of release to service and to act as L support staff for the following:
 maintenance performed on aircraft structure, power plant and mechanical and electrical systems;
 work on radio, Emergency Locator Transmitters (ELT) and transponder systems; and
 work on other avionics systems requiring simple tests to prove their serviceability.
Subcategory L2 includes subcategory L1. Any limitation to subcategory L2 in accordance with point 66.A.45(h) becomes also applicable to subcategory L1.
Subcategory L2C includes subcategory L1C.
7. A category C aircraft maintenance licence shall permit the holder to issue certificates of release to service following base maintenance of the aircraft. The privileges apply to the aircraft in its entirety.
(b) The holder of an aircraft maintenance licence may not exercise its privileges unless:
1. in compliance with the applicable requirements of Annex I (Part-M), Annex II (Part-145), Annex Vb (Part-ML) and Annex Vd (Part-CAO); and
2. in the preceding 2-year period he/she has, either had 6 months of maintenance experience in accordance with the privileges granted by the aircraft maintenance licence or, met the provision for the issue of the appropriate privileges; and
3. he/she has the adequate competence to certify maintenance on the corresponding aircraft; and
4. he/she is able to read, write and communicate to an understandable level in the language(s) in which the technical documentation and procedures necessary to support the issue of the certificate of release to service are written.
GM 66.A.20(a) Privileges
ED Decision 2020/002/R

1. The following definitions apply:
Electrical system means the aircraft electrical power supply source, plus the distribution system to the different components contained in the aircraft and relevant connectors. Lighting systems are also included in this definition. When working on cables and connectors which are part of these electrical systems, the following typical practices are included in the privileges:
 Continuity, insulation and bonding techniques and testing;
 Crimping and testing of crimped joints;
 Connector pin removal and insertion;
 Wiring protection techniques.
Avionics system means an aircraft system that transfers, processes, displays or stores analogue or digital data using data lines, data buses, coaxial cables, wireless or other data transmission medium, and includes the system’s components and connectors. Examples of avionics systems include the following:
 Autoflight;
 Communication, Radar and Navigation;
 Instruments (see NOTE below);
 In Flight Entertainment Systems;
 Integrated Modular Avionics (IMA);
 On-Board Maintenance Systems;
 Information Systems;
 Fly by Wire Systems (related to ATA27 ‘Flight Controls’);
 Fibre Optic Control Systems.
NOTE: Instruments are formally included within the privileges of the B2 and B2L with system rating ‘instruments’. However, maintenance on electromechanical and pitot-static components may also be released by a B1, B3 or L licence holder.
Simple test means a test described in approved maintenance data and meeting all the following criteria:
 The serviceability of the system can be verified using aircraft controls, switches, Built-in Test Equipment (BITE), Central Maintenance Computer (CMC) or external test equipment not involving special training.
 The outcome of the test is a unique go – no go indication or parameter, which can be a single value or a value within an interval tolerance. No interpretation of the test result or interdependence of different values is allowed.
 The test does not involve more than 10 actions as described in the approved maintenance data (not including those required to configure the aircraft prior to the test, i.e. jacking, flaps down, etc, or to return the aircraft to its initial configuration). Pushing a control, switch or button, and reading the corresponding outcome may be considered as a single step even if the maintenance data shows them separated.
Troubleshooting means the procedures and actions necessary, using approved maintenance data, in order to identify the root cause of a defect or malfunction. It may include the use of BITE or external test equipment.
Line maintenance means any maintenance that is carried out before flight to ensure that the aircraft is fit for the intended flight. It may include:
 trouble shooting;
 defect rectification;
 component replacement with use of external test equipment, if required. Component replacement may include components such as engines and propellers;
 scheduled maintenance and/or checks including visual inspections that will detect obvious unsatisfactory conditions/discrepancies but do not require extensive in depth inspection. It may also include internal structure, systems and powerplant items which are visible through quick opening access panels/doors;
 minor repairs and modifications which do not require extensive disassembly and can be accomplished by simple means;
 for temporary or occasional cases (Airworthiness Directives, hereinafter AD; service bulletins, hereinafter SB) the quality manager may accept base maintenance tasks to be performed by a line maintenance organisation provided all requirements are fulfilled. The Member State will prescribe the conditions under which these tasks may be performed.
Base Maintenance means any task falling outside the criteria that are given above for Line Maintenance.
NOTE:
Aircraft maintained in accordance with ‘progressive’ type programmes need to be individually assessed in relation to this paragraph. In principle, the decision to allow some ‘progressive’ checks to be carried out is determined by the assessment that all tasks within the particular check can be carried out safely to the required standards at the designated line maintenance station.
2. The category B3 licence does not include any A subcategory. Nevertheless, this does not prevent the B3 licence holder from releasing maintenance tasks typical of the A1.2 subcategory for piston-engine non-pressurized aeroplanes of 2 000 kg MTOM and below, within the limitations contained in the B3 licence.
3. The B1.2 and B3 licences do not include any L subcategory. Nevertheless, the holder of a B1.2 or B3 licence with the appropriate ratings is entitled to receive, upon application, licences in the L1 and L2 subcategories under the conditions described in point 66.B.110(d).
4. The privileges of the B2 licence with given aircraft ratings include the privileges of the B2L licence for all the system ratings for the same aircraft ratings. Nevertheless, the holder of a B2 licence with given aircraft ratings may apply for a B2L licence in order to include a different aircraft rating if the applicant only wants to demonstrate compliance with the experience requirements for certain system ratings.
5. The category C licence permits certification of scheduled base maintenance by the issue of a single certificate of release to service for the complete aircraft after the completion of all such maintenance. The basis for this certification is that the maintenance has been carried out by competent mechanics, and category B1, B2, B2L, B3 and L support staff, as appropriate, have signed for the maintenance tasks under their respective specialisation. The principal function of the category C certifying staff is to ensure that all required maintenance has been called up and signed off by the category B1, B2, B2L, B3 and L support staff, as appropriate, before issue of the certificate of release to service. Only category C personnel who also hold category B1, B2, B2L, B3 or L qualifications may perform both roles in base maintenance.
AMC 66.A.20(a)(4) Privileges
ED Decision 2019/009/R

‘Within the limits of the system ratings specifically endorsed on the licence’ refers to the fact that the privileges of the licence holder are limited:
 to the group/subgroup of aircraft endorsed on the licence, but also
 to the system rating(s) endorsed.
When an applicant wishes to get the privilege to issue certificates of release to service and to act as support staff for electrical and avionics tasks within powerplant and mechanical systems, he/she should apply for the rating ‘airframe system’ on the B2L licence. The reason is that the ‘airframe systems’ rating is the only rating which covers completely the electrical and avionics tasks of the powerplant and mechanical systems of the aircraft.__

But he can.

One could argue that there is a difference between weighing the aircraft and calculating the changes, look at GM1 (b), second sentence.
The weighing clearly needs to be done by an organisation as seen in NCO.POL.105 (b) but calculation might not.

Well well, who did the modification? Was it the Part-66?

A P66 can perform and release the weighing and generate the report.

It’s in the screenshots.
If your P66 installed the LED he can release them, as well as the weighing and WB report.

Source: Info/Expertise provided by https://aufwind.aero/
A team of very knowledgeable and passionate GA engineers, mechanics and pilots.

At EASA Part66 (B1/B2) can do W&B and alteration, at FAA A&P must hold IA authorization for this.
Remember that buy must have and list tools he used and this tool (scales) must be calibrated (have current calibration cert.).

An IA is not required to update N-registered aircraft weight and balance records. From the FAA Weight and Balance Handbook which is BTW a great resource for anybody to check the W&B on their aircraft:

“The airframe and powerplant (A&P) mechanic or repairman who maintains the aircraft keeps the weight and balance records current, recording any changes that have been made because of repairs or alterations.”