AD/RAD/91 Amdt 1 - Rockwell Collins TDR-94/94D Transponder - Air/Ground Discrete Inputs

The AD is built on a small set of technical and regulatory concepts found in the text:

• Applicability by equipment type and part number: The AD’s applicability is equipment‑level. It applies to “Rockwell Collins Mode S Transponders identified by type and Part Number (P/N) in Table 1,” with the P/N column explicitly marked “P/N (all serial numbers).” Table 1 lists the transponder types TDR‑94 and TDR‑94D and a set of specific P/Ns for each type.

• Aircraft scope and examples: The AD supplies a non‑exclusive list of aircraft manufacturers and models “known to be installed on, but not limited to” those aircraft types (for example ATR 42/72, Bombardier CL‑600 series, DHC‑8, Dassault Falcon series, Gulfstream G‑IV, Hawker Beechcraft 200 and 400 series, SAAB SF340A/B, Sikorsky S‑92). The language indicates the AD is aircraft‑agnostic in technical application (it targets the transponder interface) but provides illustrative platforms where the transponders are known to be installed.

• The technical failure mode: The core technical issue is an interface wiring configuration between the transponder Air/Ground discrete inputs and the aircraft weight‑on‑wheels (ground/air) signal. Rockwell Collins TDR‑94/TDR‑94D transponders have two Air/Ground discrete inputs; the AD states that “A connection to the Air/Ground #2 discrete will implement an inhibition of ATCRBS, ATCRBS/Mode‑S All‑Call and Mode‑S Only All‑Call replies when the aeroplane is on the ground. No on‑ground reply inhibition occurs if the connection is to the Air/Ground #1 discrete.” The unsafe condition therefore arises where the wiring connects the weight‑on‑wheels to #1 instead of #2 (or otherwise departs from the configuration in the SIL).

• Operational safety logic: The Directive frames the safety need around on‑ground surveillance systems: Airservices Australia and other ANSPs “have implemented Advanced Surface Movement Guidance & Control Systems (A‑SMGCS) ... providing conflict detection and alerting on runways.” The AD asserts that incorrect on‑ground transponder replies “would lead to degradation of the functioning of the A‑SMGCS” and could “increase the risk of undetected runway incursions,” thereby potentially endangering aircraft and persons on the ground.

• Remedy and compliance mechanics: The remedy is a verification against Rockwell Collins Service Information Letter (SIL) TDR‑94( ) SIL 07‑1 (25 May 2007) Table 1, and modification “in accordance with approved aeroplane modification instructions” when the wiring is not compliant. The AD does not provide detailed wiring instructions itself; it mandates conformity with the vendor SIL and approved modification instructions.

• Exceptions and cross‑referencing: Note 2 lists specific Service Bulletins and modification numbers that , if already embodied , render the Amendment not applicable. Note 3 cross‑refers to EASA AD 2010‑0067. The AD also records that the original Directive (with the same underlying requirement) “reflected the requirements of EASA AD 2009‑0097” but that this Amendment expands the scope to include helicopters after EASA advised the earlier applicability referred only to “aeroplanes.”

Those concepts together define the scope of action (inspect and fix wiring per SIL), the actors expected to act (operators/maintenance organisations using approved modification instructions), the timing (different compliance deadlines for aeroplanes and helicopters), and the safety rationale (A‑SMGCS effectiveness and runway incursion risk).

The AD directly affects three classes of actors as described in the text:

1. Operators and owners of aircraft equipped with the affected transponders. The AD’s applicability is equipment‑based: it applies to Rockwell Collins TDR‑94 and TDR‑94D transponders identified by the listed P/Ns (the table is explicit that the P/Ns are “all serial numbers”). Therefore any operator whose airframe carries one of those transponders is in scope regardless of aircraft registration or operator type. The AD lists aircraft models “known to be installed on, but not limited to” those types; that list is illustrative, not exhaustive.

2. Maintenance organisations, certified aircraft engineers and mod shops that carry out the inspection and wiring modification. The AD requires verification “in accordance with Table 1 of Rockwell Collins Service Information Letter TDR‑94( ) SIL 07‑1 ... (document reference 523‑0809129‑001000)” and prescribes that any required wiring modification be performed “in accordance with approved aeroplane modification instructions.” Those phrases allocate the technical task and decision‑making to parties responsible for complying with service information and for executing approved modifications, which will normally be the aircraft’s maintenance provider, the Original Equipment Manufacturer’s (OEM) authorised service station or an appropriately approved engineering organisation.

3. Air Navigation Service Providers and regulatory oversight bodies indirectly. The background describes Airservices Australia and other national ANSPs implementing A‑SMGCS and depending on correct transponder on‑ground behaviour. While ANSPs are not directed to act by the AD, they are the beneficiaries of the required corrections; the AD ties the corrective action to the operational needs of A‑SMGCS.

The AD carves out exemptions for aircraft that have already complied with specific Service Bulletins or modifications listed in Note 2 (for example ATR SB ATR42‑34‑0164 or ATR72‑34‑1093, Bombardier SB 601R‑34‑146, and a number of Dassault SBs and modifications). Aircraft that have those SBs or modifications embodied are explicitly stated as not applicable to this Amendment.

Who pays: the text requires verification and corrective modification “in accordance with approved aeroplane modification instructions.” The AD does not itself state who bears the cost, but mechanically it assigns the obligation to the aircraft/heli concerned (operators and their maintenance organisations) by requiring the physical inspection and any subsequent wiring modification. The AD’s compliance timelines (Requirement 1: before 26 March 2011; Requirement 2: within 12 months of the effective date) impose scheduling and resource allocation obligations on those parties.

Finally, the AD was issued by CASA (signed by Mike Higgins, Delegate of the Civil Aviation Safety Authority). The effective date is recorded as 10 May 2010, and the AD notes that the “original issue of this Directive became effective on 26 March 2010,” which indicates that operators who had already complied with the original requirement may have satisfied the obligation prior to this Amendment.

Duties

• Verify wiring configuration: For all affected aeroplanes, the AD imposes the duty to “verify that the transponder Air/Ground discrete input connections are installed in accordance with Table 1 of Rockwell Collins Service Information Letter TDR‑94( ) SIL 07‑1 dated 25 May 2007 (document reference 523‑0809129‑001000).” The same duty is explicitly repeated for “all affected helicopters.”

• Correct non‑compliance: Where wiring “is not compliant with the information provided in Table 1 of the SIL,” the duty is to “modify the aeroplane Air/Ground discrete input connections in accordance with approved aeroplane modification instructions.” The AD therefore requires a remedial modification where verification shows deviation from the SIL.

• Timing obligations: The duties carry deadlines. Requirement 1 (aeroplanes) must be satisfied “Before 26 March 2011.” Requirement 2 (helicopters) must be satisfied “Within 12 months after the effective date of this Amendment.” The Amendment effective date is 10 May 2010, so the helicopter compliance period runs to 10 May 2011.

• Reliance on approved modifications: The AD specifies that any corrective wiring must be performed according to “approved aeroplane modification instructions.” That imposes a process duty: the modification must follow an approved engineering instruction (likely an approved engineering order, STC, or manufacturer modification process), not an ad hoc fix.

Rights and practical entitlements (as implied by the text)

• Exemption if prior modification accomplished: Note 2 creates an operational right of non‑application where an aircraft has already embodied certain Service Bulletins or modifications (for example ATR modification n° 05602, Bombardier SB 601R‑34‑146, MODSUM IS8Q2450012 for DHC‑8, or specified Dassault SBs and modifications). If those SBs/mods have been embodied, the aircraft is “not applicable to this Amendment.”

• Reliance on vendor SIL: The AD directs operators to use Rockwell Collins SIL 07‑1 Table 1 as the standard for verification. That creates a right to rely on the vendor’s SIL as the normative technical reference for determining compliance.

• Time to comply: The AD grants differing lead times for aeroplanes and helicopters. Aeroplanes were given a fixed calendar compliance date (Before 26 March 2011), while helicopters were given 12 months from the Amendment’s effective date (10 May 2010), which is a different scheduling entitlement and effectively gives helicopter operators a later deadline relative to the original issue.

Procedural and authority notes drawn from the text

• The AD itself does not contain the technical wiring change instructions; instead it references another document (SIL 07‑1) and requires modifications “in accordance with approved aeroplane modification instructions.” That channels technical execution via established modification approval routes.

• The AD was issued as an amendment expanding applicability (to include helicopters); it records that EASA AD 2009‑0097 had earlier only referred to “aeroplanes,” and the Amendment corrects that omission to include helicopters because helicopters (for example Sikorsky S‑92) are known to be equipped with the affected transponders and may experience the same unsafe condition during taxiing (weight‑on‑wheels).

The AD does not set out rights to appeal, nor does it enumerate administrative enforcement procedures or penalties in the text provided. The duties, the technical reference documents and the compliance windows are the core operative obligations established by the Directive.

The AD sets mandatory inspection and modification obligations and specific compliance deadlines, but the text supplied does not enumerate civil or criminal penalties, nor does it specify the enforcement mechanisms, administrative sanctions or the procedural steps CASA will take if compliance is not met. The document records the operative requirements, the compliance dates, and the effective date, and it is signed by Mike Higgins, “Delegate of the Civil Aviation Safety Authority” (16 April 2010). The AD records the following concrete enforcement‑relevant facts:

• Required actions and deadlines: Requirement 1 must be completed “Before 26 March 2011,” and Requirement 2 “Within 12 months after the effective date of this Amendment.” The effective date is recorded as 10 May 2010.

• The AD is an instrument of CASA: It is issued by CASA (the signature line and title identify the delegate). That locates responsibility for prescribing the AD within the national civil aviation regulator.

What the AD text does not provide

• The AD does not set out penalties or sanctions for non‑compliance in the text provided. There are no monetary fines, imprisonment provisions, or administrative enforcement steps stated in the document excerpt.

• The AD does not specify how CASA will monitor or audit compliance, what documentation must be retained, or whether an operator must notify CASA when the work is complete. The only affirmative procedural instruction is to verify wiring against the SIL and modify in accordance with approved modification instructions.

How to interpret enforcement in practice (limited to the text)

• Since the AD is framed as a Directive with explicit compliance dates and is issued by CASA, it is an enforceable regulatory instrument within the aviation safety framework; however, any particulars about enforcement powers, notices, or penalties are not set out within this AD text and would be found in the broader civil aviation regulatory code and CASA procedural material that are not part of the supplied document.

• The AD identifies other regulatory instruments it interacts with , notably ICAO Annex 10 Volume IV (referenced as the ICAO specification that an aeroplane with the interface problem “does not meet”), and EASA ADs (Notes 2 and 3). These references signal the AD’s safety rationale and its place within international compliance expectations, but they do not provide direct enforcement mechanics within the instrument itself.

In short, the AD prescribes mandatory technical duties and deadlines and is issued by the national regulator, but the supplied text does not contain specific penalty provisions or a detailed enforcement protocol. Readers should treat the AD’s duties and deadlines as mandatory obligations issued by CASA and, for enforcement detail, consult the relevant civil aviation regulatory framework and CASA enforcement policies that sit outside the AD text.

The AD explicitly situates itself in relation to international standards and European Safety Agency (EASA) actions; those are the only cross‑references included in the text.

• ICAO standards: The AD states that “An aeroplane with this transponder interface problem, if not corrected, does not meet the specifications of International Civil Aviation Organisation (ICAO) Annex 10 to the Convention on International Civil Aviation Volume IV Amendment 77 Section 3.1.2.10.3.10 - Inhibition of replies.” That places the AD as a corrective measure to bring equipment configuration into conformity with ICAO Annex 10 Volume IV Amendment 77, specifically the paragraph addressing inhibition of transponder replies when on the ground. The AD frames the domestic requirement as necessary to meet those international technical specifications for radio navigation and comms replies.

• EASA ADs: The AD makes two explicit references to European Aviation Safety Agency material. Note 3 states “EASA AD 2010‑0067 refers.” The background explains that the “original issue of this Directive reflected the requirements of EASA AD 2009‑0097,” but EASA had advised that the applicability in that AD “only referred to ‘aeroplanes’ ... inadvertently implying that no helicopters could be affected.” That exchange underpins this Amendment’s expansion to include helicopters. Thus the AD interacts with, and follows, EASA corrective ADs by mirroring their technical focus while amending scope where EASA’s wording unintentionally narrowed applicability.

• National ANSP operational requirements: The AD references Airservices Australia, the Australian ANSP, and the implementation of A‑SMGCS systems by Airservices and other national ANSPs. The AD’s safety rationale is operational: correct inhibition of transponder replies when the aeroplane is on the ground is necessary to ensure “proper and effective operation of the A‑SMGCS.” This links the AD to ANSP operational systems, though the AD does not create duties for ANSPs; rather it imposes hardware/configuration duties on aircraft operators to ensure ANSP systems function as designed.

• Service information and approved modifications: The AD compels conformity with Rockwell Collins Service Information Letter TDR‑94 SIL 07‑1 (25 May 2007) Table 1, and requires rectification using “approved aeroplane modification instructions.” These references indicate an interaction between the AD and the body of manufacturer technical records and the airworthiness approval processes for modifications (for example, STCs, engineering orders or approved design changes). The AD does not itself create approvals; it requires that any modification be made in accord with existing approved modification pathways.

• Identified exclusions: Note 2 lists specific manufacturer Service Bulletins and modification numbers (ATR SB ATR42‑34‑0164, ATR72‑34‑1093 mod n° 05602, Bombardier SB 601R‑34‑146, MODSUM IS8Q2450012 for DHC‑8, and multiple Dassault SBs/modifications). Those references operate as carve‑outs: aircraft that have those SBs/mods embodied are stated as not applicable to this Amendment. This produces an interaction between the AD and previously implemented manufacturer instructions; where earlier work has been done to the specified standard, the AD’s mandate does not apply.

What the AD does not do

• The AD does not modify or supersede civil aviation statutes or enumerate how CASA will exercise enforcement powers under general aviation law; those interactions would be governed by the wider body of law and CASA policies, which are not reproduced in the AD.

• The AD does not itself create or alter ANSP operational rules; it is remedial to ensure aircraft equipment behaviour aligns with existing A‑SMGCS and ICAO expectations.

In sum, the AD references and enforces alignment with ICAO Annex 10 requirements, follows and modifies the scope of related EASA ADs, relies on manufacturer SILs and approved modification processes, and takes operational requirements of ANSP A‑SMGCS implementations as the underlying safety driver. The AD’s direct legal force is domestic, while its technical rationale ties into international and European safety standards.

The AD text provides a brief amendment history and provenance:

• Original Directive: The text records that “The original issue of this Directive became effective on 26 March 2010.” That original issue implemented the initial requirement to check transponder Air/Ground discrete input connections and to accomplish corrective action where discrepancies were found. The AD’s Background paragraph explains the original Directive reflected EASA AD 2009‑0097’s requirements.

• This Amendment: The present document is labelled “AD/RAD/91 Amdt 1” and is dated as becoming effective on 10 May 2010 (“This Amendment becomes effective on 10 May 2010”). The signature block records Mike Higgins, Delegate of the Civil Aviation Safety Authority, 16 April 2010. The Amendment’s primary mechanical change was an expansion of applicability to include helicopters. The Background states:

  • EASA AD 2009‑0097 only referred to “aeroplanes,” “inadvertently implying that no helicopters could be affected,” and since some helicopters (for example the Sikorsky S‑92) are known to be equipped with the affected transponders and the unsafe condition can occur during helicopter taxiing (weight‑on‑wheels), the Amendment expands applicability to helicopters.

• Related EASA activity: The AD also cross‑refers to EASA AD 2010‑0067 (Note 3: “EASA AD 2010‑0067 refers”), indicating a continuing sequence of European AD activity on the same technical problem. The Background discusses the EASA advisory that prompted the Amendment’s scope expansion.

• Prior technical publication: The AD relies on Rockwell Collins Service Information Letter TDR‑94 SIL 07‑1 dated 25 May 2007 (document reference 523‑0809129‑001000) as the operative technical standard for correct Air/Ground discrete input installation. That SIL predates both the original Directive and the Amendment and is the vendor document that specifies the required wiring configuration (Table 1 of the SIL).

• Exemptions due to earlier modifications: Note 2 lists specific manufacturer Service Bulletins and modification numbers which, if already embodied on an aeroplane, render the Amendment not applicable to that aircraft. Those listed SBs and mods are in effect part of the AD’s amendment history in that previously adopted SBs or mods remove the need to re‑comply with the AD for those aircraft.

The Amendment’s explicit purpose was to correct the earlier omission that had limited applicability language to “aeroplanes” and to ensure that helicopters known to be equipped with the affected units fall within the corrective requirement. The AD records the effective dates for both the original issue and the Amendment and indicates that the original Directive required inspection and correction; the Amendment retains that operational requirement while extending the population in scope.

The supplied AD text contains no litigation history, no judicial decisions, and no references to court proceedings. The document records administrative steps and cross‑references to ICAO and EASA material, and it shows the internal administrative chronology (original Directive effective 26 March 2010; this Amendment effective 10 May 2010) and the signature of the CASA delegate (Mike Higgins, 16 April 2010). It does, however, make regulatory references that could be material in any legal challenge (for example the reliance on ICAO Annex 10 and EASA ADs), but the AD text itself contains no mention of litigation, appeals, or disputes arising from the Directive.

Because the AD is an administrative safety instrument rather than a statutory enactment reproduced here, any litigation that might arise from enforcement, disputed applicability or the engineering remedies required would be governed by the broader administrative law and civil aviation regulatory framework. Those materials are not part of the supplied text, and this AD does not report any case law, appeals, or judicial reviews. The explicit absence of litigation references in the AD means that, based on the source, there is no litigation history to report.

Readers requiring litigation records should consult court databases, CASA enforcement records, and administrative tribunal decisions outside the AD text.

The AD contains several technical and practical pitfalls that operators, maintenance organisations and compliance teams should note, each grounded in the AD wording:

• Equipment‑based applicability, not serial‑limited: The AD lists P/Ns with the descriptor “(all serial numbers).” That means the applicability does not exclude particular serial‑number ranges; any unit bearing a listed P/N is in scope. A common operator mistake would be to assume only specific serial numbers are covered; the AD’s “all serial numbers” language rejects that.

• The difference between Air/Ground #1 and #2 is determinative: The AD’s safety problem rests on which discrete input the weight‑on‑wheels signal is wired to. The text makes this explicit: “A connection to the Air/Ground #2 discrete will implement an inhibition ... No on‑ground reply inhibition occurs if the connection is to the Air/Ground #1 discrete.” Thus a superficial check that only verifies presence of a ground sensing connection, without confirming it is tied to #2 per the SIL Table 1, would not meet the AD’s verification requirement.

• Reliance on vendor SIL Table 1: The AD does not reproduce the wiring table; it requires verification “in accordance with Table 1 of Rockwell Collins Service Information Letter TDR‑94( ) SIL 07‑1 dated 25 May 2007.” Failure to use the correct revision and document reference would be a procedural error. The AD also requires remedial action “in accordance with approved aeroplane modification instructions,” so simply following the SIL without following approved modification approval processes may not satisfy the AD.

• Exclusions are narrow and specific: Note 2 excludes aircraft that have complied with listed Service Bulletins or embody certain modifications. Those SBs and mod numbers are specific (for example ATR SB ATR42‑34‑0164 or SB ATR72‑34‑1093 modification n° 05602; Bombardier SB 601R‑34‑146; MODSUM IS8Q2450012 for DHC‑8; and a set of Dassault SBs and modifications). Operators must confirm that the specific SB/mod number is embodied; a generic SB or unrelated modification will not suffice.

• Different compliance timelines for aeroplanes and helicopters: Requirement 1 (aeroplanes) must be done “Before 26 March 2011”; Requirement 2 (helicopters) must be done “Within 12 months after the effective date of this Amendment.” Since the Amendment’s effective date is 10 May 2010, helicopter compliance runs to 10 May 2011, whereas aeroplane compliance is set to 26 March 2011 , earlier. Misreading or conflating the two timelines could lead to late compliance for one class.

• Illustrative aircraft list is not exhaustive: The AD lists aircraft models “known to be installed on, but not limited to” a set of models. That phrase means operators of other models should not assume exemption simply because their aircraft model is not listed; instead they must check whether their aircraft have one of the listed transponder P/Ns. The AD’s applicability hinges on the transponder P/N, not the aircraft model per se.

• Helicopter omission in earlier EASA wording: The AD explains the Amendment arose because EASA’s earlier AD wording inadvertently implied no helicopters were affected. Operators and maintainers should not assume that EASA’s earlier aeroplane‑only wording exempted helicopters if helicopter serials carry the listed P/Ns; the CASA Amendment corrects that misunderstanding and explicitly covers helicopters.

• No procedural detail on modification approvals or record‑keeping in the AD: The AD mandates modification “in accordance with approved aeroplane modification instructions” but does not set out approval routes, forms, or documentary evidence to be lodged. That leaves practical questions about how inspectors will accept compliance: operators should ensure the modification route followed is an approved design change and retain documentary proof that the SIL was followed and the approved modification was used.

• The AD references international specifications (ICAO Annex 10): The AD frames the requirement as necessary to meet international standards. Some operators might see this as an international obligation, but compliance remains a domestic AD obligation.

In sum, the technical specificity (Air/Ground #2 vs #1), the reliance on a specific SIL table, the all‑serial‑numbers applicability, and the tight but different compliance dates across aeroplanes and helicopters are the principal operational pitfalls to watch for.

The AD prescribes a short, discrete compliance workflow. The following steps are grounded in the AD wording; they represent the minimum actions the AD requires:

1. Identify affected units on the fleet

   • Determine whether the aircraft or helicopter is equipped with a Rockwell Collins TDR‑94 or TDR‑94D Mode S transponder bearing one of the P/Ns listed in Table 1 of the AD. The AD states the P/N column applies to “all serial numbers,” so any matching P/N is in scope regardless of serial number.

2. Determine whether Note 2 exclusions apply

   • Check whether the aircraft has already complied with any Service Bulletin or modification listed in Note 2 (for example, ATR SB ATR42‑34‑0164 or ATR72‑34‑1093 modification n° 05602; Bombardier SB 601R‑34‑146; MODSUM IS8Q2450012 for DHC‑8; listed Dassault SBs and modification numbers). If the specified SB or modification is embodied, the AD states the Amendment “is not applicable” to that aircraft.

3. Verify wiring per Rockwell Collins SIL Table 1

   • For aircraft not excluded, perform the verification required by the AD: “verify that the transponder Air/Ground discrete input connections are installed in accordance with Table 1 of Rockwell Collins Service Information Letter TDR‑94( ) SIL 07‑1 dated 25 May 2007 (document reference 523‑0809129‑001000).”
   • The verification step requires accessing the stated SIL and comparing actual wiring connections to the Table 1 configuration. The AD does not reproduce the table; it mandates compliance with it.

4. If wiring is not compliant, arrange corrective modification

   • Where the verification finds non‑compliance, the AD requires that you “modify the aeroplane Air/Ground discrete input connections in accordance with approved aeroplane modification instructions.”
   • Ensure the modification is an approved design change or embodied under an approved modification instruction (for example, an OEM modification, approved engineering order, or regulatory‑approved design change). The AD’s requirement is to use approved modification instructions; ad hoc wiring changes without design approval will not meet the AD’s mandated standard.

5. Observe the compliance windows

   • For aeroplanes: complete Requirement 1 “Before 26 March 2011.”
   • For helicopters: complete Requirement 2 “Within 12 months after the effective date of this Amendment,” and the AD records the effective date as 10 May 2010, which sets the helicopter compliance completion date at 10 May 2011.
   • Note the AD’s original issue was effective 26 March 2010 and this Amendment was effective 10 May 2010. Operators must ensure the applicable compliance date for their aircraft class is met.

6. Maintain evidence of compliance

   • While the AD text does not specify record‑keeping requirements, good practice consistent with the AD is to record the verification step (who checked, when, what was examined), the SIL revision used, and the approved modification instruction reference and embodiment evidence where corrective work was done. Retain engineering, maintenance release and modification approval documentation to demonstrate the AD was complied with in accordance with the required technical references.

7. Coordinate with maintenance and regulatory channels

   • Since the AD requires modifications “in accordance with approved aeroplane modification instructions,” ensure the maintenance organisation, the design authority or the OEM is engaged to provide the approved modification pathway and that the work is signed off by authorised personnel.

8. Consider ANSP and operational implications

   • The AD’s safety rationale ties compliance to A‑SMGCS functioning. Operators should schedule the verification and any rectification in a manner that minimises operational disruption but meets the specified deadlines.

9. If unsure, seek clarification from CASA or the OEM

   • The AD references an OEM SIL and approved modification routes. If there is ambiguity about whether a particular SB/mod qualifies under Note 2, or which approved modification instruction to use, obtain clarification from the OEM, the operator’s continuing airworthiness management organisation, or CASA.

This sequence follows directly from the AD text: identify affected P/Ns, check Note 2 exemptions, verify wiring against Rockwell Collins SIL Table 1, and, if necessary, correct the wiring via approved modification instructions within the deadline. The AD does not prescribe alternate mitigations or temporary measures; it requires the verification and any needed modifications be completed by the stated dates.