{"id":"F2005L02070","name":"AD/CESSNA 170/77 - Main Electrical Power Junction Box","slug":"ad-cessna-170-77-main-electrical-power-junction-box","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":36266,"registerId":"commonwealth-F2005L02070-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Cessna 170, 172, F172, FR172 and 175 Ser","sectionType":"division","heading":"Cessna 170, 172, F172, FR172 and 175 Series Aeroplanes","content":"### Cessna 170, 172, F172, FR172 and 175 Series Aeroplanes\n\n| AD/CESSNA 170/77 | Main Electrical Power Junction Box | 9/2005 |\n| ---------------- | ---------------------------------- | ------ |\n\n```html\n

Applicability:

Cessna Model 172R and 172S aeroplanes as follows:

Model

Serial Numbers

172R
172S

17281186 through 17281232
172S9476 through 172S9689 and 172S9691 through 172S9770 inclusive

Requirement:

1. Unless already accomplished, inspect any MC01-3A I.C. 9 (part number (P/N) S3100-297) or MC01-3A I.C. 10 (P/N S3100-344) main electrical power junction box for any incorrect amperage (amp) circuit beaker installed in place of the required 40-amp circuit breakers in accordance with Cessna Service Bulletin (SB) SB05-24-01 dated 31 January 2005.

2. Replace any incorrect amp circuit breaker found during the Requirement 1 inspection with the required 40-amp circuit breaker in accordance with
SB05-24-01.

3. Only 40-amp circuit breakers may be installed as spares in any MC01-3A I.C. 9 or MC01-3A I.C. 10 main electrical power junction box.

Later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2005-13-10, are considered acceptable for compliance with the equivalent Requirements of this Directive.

Note: FAA AD 2005-13-10 Amdt 39-14147 refers.

Compliance:

For Requirement 1 - Within the next 30 days after the effective date of this Directive.

For Requirement 2 - Before further flight after the Requirement 1 inspection.

For Requirement 3 - As of the effective date of this Directive.

This Airworthiness Directive becomes effective on 1 September 2005.

\n```\n\n| Background: | The FAA has received several reports of circuit breakers that are not the correct40-amp circuit breaker installed in the MC01-3A main electrical power junction box. Incorrectly rated circuit breakers could result in premature tripping of the power junction box main feeder circuit breakers and could lead to partial or complete loss of all electrical power on the airplane. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Directive requires the inspection of the main electrical power junction box and, if necessary, the replacement of any incorrect circuit breaker |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n22 July 2005","sortOrder":0},{"sectionNumber":"AD/CESSNA 170/77","sectionType":"part","heading":"AD/CESSNA 170/77","content":"## AD/CESSNA 170/77","sortOrder":1},{"sectionNumber":"Main Electrical Power Junction Box","sectionType":"part","heading":"Main Electrical Power Junction Box","content":"## Main Electrical Power Junction Box","sortOrder":2},{"sectionNumber":"9/2005","sectionType":"part","heading":"9/2005","content":"## 9/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This Directive implements the FAA AD requirement for the listed models and serial numbers to inspect and replace incorrectly rated breakers; it does not broaden applicability beyond the specified aircraft or add new types of obligations. It permits later revisions of SB05‑24‑01 as FAA‑approved AMOCs, preserving alignment with the original FAA approach (see 'Later revisions ... AMOC' and Note referencing FAA AD 2005‑13‑10)."},"complexity_factors":["Narrow applicability: specific to Cessna 172R and 172S serial-number ranges (Applicability).","Few, prescriptive actions: three operative requirements—inspect, replace incorrect breakers, and restrict spares to 40‑amp units (Requirements 1–3).","Tight, clear timeframes: inspection within 30 days; replacement before further flight; spares rule effective immediately (Compliance section).","Dependency on an external technical document for procedure: compliance linked to Cessna SB05‑24‑01 (Requirements 1–2).","Acceptance of later SB revisions as FAA‑approved AMOCs introduces a controlled alternative compliance route (text on later revisions/AMOC).","Safety‑critical outcome (risk of partial/complete electrical loss) raises enforcement priority but does not add procedural or interpretive complexity (Background)."],"plain_english_summary":"**Requires inspection and, if needed, replacement of circuit breakers in the MC01‑3A main electrical power junction box on specified Cessna 172R/172S aircraft per Cessna Service Bulletin SB05‑24‑01.** Only 40‑amp circuit breakers may be fitted or held as spares. The directive targets the listed serial-number ranges, sets an inspection deadline of 30 days, and requires any incorrect breakers to be replaced before further flight to address reports of premature tripping that could cause partial or total electrical power loss."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with a narrow, specific safety purpose. It addresses exactly one technical issue (incorrect circuit breaker amperage in a specific junction box) for a limited fleet of aircraft. There is no indication of scope creep; the directive matches its original intent of addressing the safety defect described in the background section."},"complexity_factors":["Short, single-purpose directive with only 3 requirements","Limited applicability: only 2 specific aircraft models with defined serial number ranges","Clear compliance deadlines tied to specific events (30 days, before further flight, effective date)","References external technical document (Cessna Service Bulletin SB05-24-01) for detailed procedures","Cross-reference to US FAA Airworthiness Directive (AD 2005-13-10) for alternative compliance methods","No nested exceptions or conditional logic — straightforward 'inspect and replace if wrong' structure","Contains some aviation-specific terminology (AMOC, SB, P/N) but these are standard in the field"],"plain_english_summary":"This CASA Airworthiness Directive orders owners, operators, and maintenance personnel of certain Cessna 172R/S (serials built ~1997–2005) to inspect the main electrical power junction box within 30 days for incorrectly installed circuit breakers and replace any non‑40‑amp breakers with the correct 40‑amp units before further flight. It also mandates using only 40‑amp spares going forward to prevent inadvertent total electrical power loss in flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-170-77-main-electrical-power-junction-box","history":"/api/acts/ad-cessna-170-77-main-electrical-power-junction-box/history","analysis":"/api/acts/ad-cessna-170-77-main-electrical-power-junction-box/analysis","conflicts":"/api/acts/ad-cessna-170-77-main-electrical-power-junction-box/conflicts","importantCases":"/api/acts/ad-cessna-170-77-main-electrical-power-junction-box/important-cases","documents":"/api/acts/ad-cessna-170-77-main-electrical-power-junction-box/documents"}}