{"id":"F2008L01363","name":"AD/CESSNA 170/83 - Alternate Static Air Source Valve","slug":"ad-cessna-170-83-alternate-static-air-source-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":73622,"registerId":"commonwealth-F2008L01363-current","compilationNumber":null,"startDate":"2026-04-02","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 170/83 | Alternate Static Air Source Valve | 7/2008 TX |\n| ---------------- | --------------------------------- | --------- |\n\n```html\n

Applicability:

Aeroplanes models listed in Table 1 and Table 2 that have an alternate static air source selector valve, part number (P/N) 2013142-18, installed after 19 November 2007.

Note 1: Aircraft listed in Table 1 had an alternate static air source selector valve, P/N 2013142-18, installed during manufacture but may have also had the affected part installed as a replacement part.

Table 1 - Applicability for Aeroplanes that Had
the Affected Part Installed at Manufacture

Model

Serial Numbers

172S

172S10672 through 172S10674, 172S10676, 172S10678 through 172S10680, 172S10682, 172S10683 and 172S10685

Table 2 - Applicability for Aeroplanes that Could Have Had the Affected
Part Installed as a Replacement Part or From Parts Held as Spares

Model

Serial Numbers (S/N)

172
172R
172S
F172D
F172E
F172F
F172G
F172H
F172K
F172L
F172M
F172N
F172P
FR172E
FR172F

All S/Ns
All S/Ns beginning with 17280001
172S8001 through 172S10671
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns

\n```\n\n```html\n

FR172G
FR172H
FR172J
FR172K
P172D
R172E (USAF T–41B) (USAF T–41C and D)
R172F (USAF T–41)
R172G (USAF T–41C or D)
R172H (USAF T–41D)
R172J
R172K
172RG

All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns
All S/Ns

Note 2: P/N 2013142-18 replaced P/Ns 2013142-9, -13 and -17.

Requirement:

1. For aeroplanes listed in Table 1 - Inspect the alternate static air source selector valve to assure that the part number identification placard is not obstructing the port as follows:

a. Adjust the pilot and copilot seats as far aft as possible.

b. Use a flashlight and mirror to inspect the alternate static air source selector valve to assure the port on the forward end of the valve is clearly visible and not covered by the part number identification placard.

2. For aeroplanes listed in Table 2 - Either:

a. Inspect the alternate static air source selector valve in accordance with Requirement 1, or

b. Inspect the aeroplane’s maintenance records to determine if the alternate static air source selector valve has been replaced since 19 November 2007 with P/N 2013142-18, if the valve has not been replaced no further action is necessary.

Note 3: The Requirement 2.b. inspection and determination may be accomplished and certified for by the aeroplane operator, provided that they hold at least a private pilot’s licence.

3. If the Requirement 2.b. determination indicates that a P/N 2013142-18 alternate static air source selector valve has been installed inspect the valve in accordance with Requirement 1.

\n```\n\n| | 4. If, during any requirement 1 inspection, the alternate static air source selector valve port is found obstructed by the part number identification placard, remove the placard from the valve body, discard the placard and assure that the port is open and unobstructed. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | 5. Static air source selector valves P/N 2013142-18 installed as modification or replacement parts on or after the effective date of this Directive must be inspected in accordance with Requirement 1 prior to installation. |\n| | Note 4: FAA AD 2008-10-02 Amdt 39-15508, which becomes effective on 12 May 2008, refers. |\n| Compliance: | For Requirements 1, 2 and 3 - Before further flight after the effective date of this Directive. |\n| | For Requirement 4 - Before further flight after the Requirement 1 inspection. |\n| | For Requirement 5 - As of the effective date of this Directive. |\n| | This Airworthiness Directive becomes effective on 13 May 2008. |\n| Background: | The United States Federal Aviation Administration (FAA) has received reports of improper installation of the part number identification placard on alternate static air source selector valves of certain Cessna 172, 175, 180, 182, 185, 206, 207, 208, 210 and 303 series aeroplanes. The part number identification placard refers to alternative air source selector valves, part number 2013142-18 that were manufactured between 20 November 2007 and 18 February 2008. The part number identification placard was installed on the valve body in a location that covers the port, which is the inlet for static air reference into the valve. The problem was discovered during a quality control check. |\n| | The FAA has advised that all parts held in stock at Cessna have been corrected and that Cessna has no way of verifying how many of these assemblies were manufactured and sent to the field with the part number identification placard installed over the alternate static air source selector valve port. The Civil Aviation Safety Authority (CASA) has no way of determining which aeroplanes have the remaining problem alternate static air source selector valve assemblies installed without having all of the affected aeroplanes and spares stock inspected. |\n| | This condition, if not corrected, could result in the altimeter, airspeed and vertical speed indicators displaying erroneous indications. This could cause the pilot to react to incorrect flight information and possibly result in loss of control. |\n\n| | CASA has varied the inspection requirements to allow the aeroplane operator to determine if a P/N 2013142-18 selector valve has been installed since 19 November 2007. Aeroplanes that may have had the selector valve installed during manufacture will still have to be inspected. |\n| --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n6 May 2008","sortOrder":0},{"sectionNumber":"AD/CESSNA 170/83","sectionType":"part","heading":"AD/CESSNA 170/83","content":"## AD/CESSNA 170/83","sortOrder":1},{"sectionNumber":"Alternate Static Air Source Valve","sectionType":"part","heading":"Alternate Static Air Source Valve","content":"## Alternate Static Air Source Valve","sortOrder":2},{"sectionNumber":"7/2008 TX","sectionType":"part","heading":"7/2008 TX","content":"## 7/2008 TX","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This AD varies the FAA's baseline inspection approach by adding a records‑check alternative for aircraft that could have received the valve as a replacement (Table 2). CASA explicitly allowed the operator (if holding at least a private pilot licence) to certify the records check (Note 3). That variation broadens the compliance pathway (lessens the number of immediate on‑aircraft physical inspections) compared with a rule requiring universal physical inspection, thereby shifting some detection responsibility onto operators and maintenance records rather than mandating inspection of every potentially affected airframe."},"complexity_factors":["Two applicability groups (Table 1: aircraft with affected part installed at manufacture; Table 2: aircraft that could have the part as replacement/spare)","Five numbered Requirements with conditional branching (e.g. Table 2: either physical inspection or records check, then follow‑up if P/N present)","Several cross‑references to Notes (Note 1–Note 4) modifying who may certify or informing part number lineage","Serial‑number lists across two tables (some 'all S/Ns', some specific ranges) requiring S/N matching","Simple technical inspection procedure (seat adjustment, flashlight/mirror) but strict compliance timing (before next flight)"],"plain_english_summary":"**What this directive does**\n\n- This Airworthiness Directive (AD) requires visual checks of an \"alternate static air source selector valve\" (a small valve that provides static air to instruments) on certain Cessna 170/172/175-series aeroplanes. The checks are intended to make sure the valve's part‑number identification placard is not blocking the valve port (the inlet for static air). (See Requirement 1 and Tables 1–2.)\n\n**Who is affected**\n\n- Owners and operators of the Cessna models and serial numbers listed in Table 1 and Table 2 where the affected valve (part number P/N 2013142-18, or its predecessors P/Ns 2013142-9, -13 and -17) is or could be installed.\n- Aircraft that had the valve installed at manufacture are automatically subject to the on-aircraft inspection (Table 1). Aircraft that could have had the valve fitted as a replacement or from spares must either have the valve inspected or have maintenance records checked to confirm whether that P/N was installed after 19 November 2007 (Table 2; Note 3 allows the operator to certify the records check if they hold at least a private pilot licence).\n\n**What you must do (mechanics)**\n\n- Inspect the valve so the forward port is clearly visible and not covered by the part number placard: move pilot and copilot seats full aft, use a flashlight and mirror to view the valve port (Requirement 1).\n- For aeroplanes in Table 2: either do the physical inspection above (Requirement 1) or check maintenance records to see if P/N 2013142-18 was installed since 19 November 2007; if there was such an installation you must then perform the physical inspection (Requirements 2 and 3; Note 3 permits an appropriately‑licensed operator to certify the records check).\n- If the inspection finds the placard obstructing the port, remove and discard the placard and make sure the port is open before flight (Requirement 4).\n- Any P/N 2013142-18 valves fitted as a modification or replacement on or after the AD’s effective date must be inspected prior to installation (Requirement 5).\n- Timing: the inspections required by Requirements 1–3 must be done before the next flight after the AD’s effective date; placard removal (Requirement 4) before further flight after the inspection; pre-install inspection (Requirement 5) is effective immediately (Compliance section).\n\n**Why it matters (stated safety concern and testing of that claim)**\n\n- Stated problem: some valves were shipped with the part number placard mounted over the valve port. That port is the static air inlet used by the altimeter, airspeed indicator and vertical speed indicator; if blocked, those instruments can give erroneous readings and could cause incorrect pilot reactions and loss of control (Background).\n- Practical effect: a simple obstruction (adhesive placard over a port) can cause instrument error. The AD's remedy is a low‑technical, direct fix — ensure the port is visible and unobstructed and remove any obstructing placard.\n\n**Who pays, who decides, and how behaviour changes**\n\n- Who pays: aircraft owners/operators bear the inspection and any corrective action costs (time for inspection, minor tooling such as flashlight/mirror). If more extensive corrective work were required in specific cases (not stated as typical), the owner would pay for that too. (See Requirements 1–5.)\n- Who decides: the operator/owner performs or arranges the inspection. For the records check option (Table 2), an operator holding at least a private pilot licence may certify the check (Note 3). The regulator (CASA) issued the AD and set the compliance timing.\n- Behaviour change: operators must check affected aircraft and affected spare/repair parts before next flight; suppliers/installers must inspect this valve before installing it as a replacement after the AD effective date (Requirement 5).\n\n**Costs, incentives, trade‑offs and implementation risks**\n\n- Direct compliance cost is small for an in‑place inspection (seat adjustment, flashlight/mirror, time to inspect) and immediate if done before next flight. This is a one‑off or occasional check for affected aircraft and parts.\n- The records‑check option reduces inspection labour where reliable maintenance logs exist, shifting the choice to the operator. That lowers inspection cost but increases risk where records are incomplete or inaccurate (Requirement 2.b and Note 3).\n- Opportunity cost: aircraft may be grounded until the inspection is completed because the AD requires action before further flight (Compliance). That creates short‑term operational disruption for aircraft scheduled to fly imminently.\n- Implementation risk: since some parts may be in the field or in stock unlabelled, the regulator cannot determine affected aircraft without inspections (Background). The AD therefore places the detection burden on operators.\n- Market effect: the measure imposes minor compliance costs on owners/operators but does not restrict ownership, transfer or operation beyond the inspection and minor corrective action required; it does not affect competition or pricing materially for operators other than the administrative/time cost of compliance.\n\n**Concrete mechanism for safety**\n\n- The AD removes a physical obstruction (placard) that can block the static inlet on a valve. The inspection and removal mechanism directly addresses the identified failure mode (placard over inlet) and prevents instrument errors caused by that blockage (Requirements 1 and 4).\n\n(Primary references: Applicability, Table 1 and Table 2; Requirements 1–5; Notes 1–4; Compliance and Background sections of the AD.)"},"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":4,"scope_assessment":{"changed":false,"description":"This AD maintains focused scope on the specific defective valve part (P/N 2013142-18) and the specific Cessna models potentially affected. The dual-path compliance option (physical inspection vs records review) is a variation in enforcement approach rather than scope expansion — it actually narrows the physical inspection burden by allowing record-checking alternatives. The scope remains tightly bound to the original safety defect identified by the FAA."},"complexity_factors":["Multiple applicability tables (Table 1 vs Table 2) with different compliance paths","Nested conditional logic: Requirement 2 offers two alternative compliance methods (2a physical inspection vs 2b records check), with Requirement 3 triggering back to Requirement 1 if 2b finds a replacement","Date-based applicability threshold (19 November 2007) creating temporal conditionality","Cross-reference to FAA AD 2008-10-02 for background context","Specific part number tracking (P/N 2013142-18) and its replacement history (superseding P/Ns 2013142-9, -13, -17)","Delegated authority signature block and effective date mechanics"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of specified Cessna 170/172/175 (and related) aircraft with alternate static air source selector valve P/N 2013142‑18 installed after 19 Nov 2007 to confirm the valve’s placard is not covering the static port. A blocked port can cause false altimeter, airspeed and VSI readings.\n\nAffected operators must inspect (or, for some aircraft, check maintenance records) and remove the placard if it blocks the port before next flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-170-83-alternate-static-air-source-valve","history":"/api/acts/ad-cessna-170-83-alternate-static-air-source-valve/history","analysis":"/api/acts/ad-cessna-170-83-alternate-static-air-source-valve/analysis","conflicts":"/api/acts/ad-cessna-170-83-alternate-static-air-source-valve/conflicts","importantCases":"/api/acts/ad-cessna-170-83-alternate-static-air-source-valve/important-cases","documents":"/api/acts/ad-cessna-170-83-alternate-static-air-source-valve/documents"}}