ETSO-2C522

• ED Decision 2022/018/R found in: CS-ETSO Amdt 17 - European Technical Standard Orders (Oct 2026)

#### ETSO-2C522 *ED Decision 2022/018/R* ##### Helicopter Terrain Awareness and Warning System (HTAWS) Advanced Features **1 Applicability** This ETSO provides the requirements that helicopter terrain awareness and warning system (HTAWS) advanced features that are designed and manufactured on or after the date of this ETSO must meet in order to be identified with the applicable ETSO marking. **2 Procedures** 2.1 General The applicable procedures are detailed in CS-ETSO, [Subpart A](#_DxCrossRefBm920220672). 2.2 Specific None. **3 Technical conditions** 3.1 Basic 3.1.1 Minimum Performance Standard The applicable standard is that provided in Table 1 for the intended equipment class. ***Table 1 — Equipment class standards*** <table bgcolor="#d9d9d9" cellpadding="7" cellspacing="0"> <col/> <col/> <col/> <tr valign="top"> <td bgcolor="#808080"><p> <b>Equipment class</b></p> </td> <td bgcolor="#808080"><p> <b>Equipment type</b></p> </td> <td bgcolor="#808080"><p> <b>Minimum Performance Standards</b></p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> Helicopter Offshore Operations (HOFO)</p> </td> <td bgcolor="#d9d9d9"><p> Offshore Helicopter Terrain Awareness and Warning System (HTAWS)</p> </td> <td bgcolor="#d9d9d9"><p> EUROCAE ED-285 ‘Minimum Operational Performance Standard for Offshore Helicopter Terrain Awareness and Warning System (HTAWS)’ dated March 2021.</p> </td> </tr> </table> Table 2 describes the modes covered by this ETSO standard. ***Table 2 — HTAWS modes*** <table bgcolor="#d9d9d9" cellpadding="7" cellspacing="0"> <col/> <col/> <col/> <thead> <tr valign="top"> <td bgcolor="#808080" colspan="2"><p align="left"> <b>Mode</b></p> </td> <td bgcolor="#808080"><p align="left"> <b>Equipment class HOFO</b></p> </td> </tr> </thead> <tbody> <tr valign="top"> <td bgcolor="#d9d9d9"><p> 1</p> </td> <td bgcolor="#d9d9d9"><p> Excessive rate of descent</p> </td> <td bgcolor="#d9d9d9"><p> Required</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> 3A</p> </td> <td bgcolor="#d9d9d9"><p> Altitude loss during take-off</p> </td> <td bgcolor="#d9d9d9"><p> Required</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> 3B</p> </td> <td bgcolor="#d9d9d9"><p> Loss of airspeed during take-off</p> </td> <td bgcolor="#d9d9d9"><p> Required</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> 4A</p> </td> <td bgcolor="#d9d9d9"><p> Flight near terrain when not in landing configuration</p> </td> <td bgcolor="#d9d9d9"><p> Required</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> 4B</p> </td> <td bgcolor="#d9d9d9"><p> Flight near terrain when in landing configuration</p> </td> <td bgcolor="#d9d9d9"><p> Required</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> 5</p> </td> <td bgcolor="#d9d9d9"><p> Excessive downward glideslope/glidepath deviation</p> </td> <td bgcolor="#d9d9d9"><p align="left"> ILS: Required<br/> GLS/LPV: Optional</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> 7A</p> </td> <td bgcolor="#d9d9d9"><p> Airspeed versus total torque</p> </td> <td bgcolor="#d9d9d9"><p> Optional</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> 7B</p> </td> <td bgcolor="#d9d9d9"><p> Vortex ring state</p> </td> <td bgcolor="#d9d9d9"><p> Optional</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> N/A</p> </td> <td bgcolor="#d9d9d9"><p> Fixed altitude callout</p> </td> <td bgcolor="#d9d9d9"><p> Optional</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> N/A</p> </td> <td bgcolor="#d9d9d9"><p> Terrain display</p> </td> <td bgcolor="#d9d9d9"><p> Not covered*</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> N/A</p> </td> <td bgcolor="#d9d9d9"><p> Forward looking terrain avoidance (FLTA)</p> </td> <td bgcolor="#d9d9d9"><p> Not covered*</p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p> N/A</p> </td> <td bgcolor="#d9d9d9"><p> Radio altitude interface</p> </td> <td bgcolor="#d9d9d9"><p> Not covered*</p> </td> </tr> <tr> <td bgcolor="#d9d9d9" colspan="3" valign="top"><p> * Local regulations on air operations may require additional modes as defined in ETSO-C194, ‘Helicopter Terrain Awareness and Warning System (HTAWS)’.</p> </td> </tr> </tbody> </table> 3.1.2 Environmental Standard See CS-ETSO, Subpart A, paragraph 2.1. 3.1.3 Software See CS-ETSO, Subpart A, paragraph 2.2. 3.1.4 Airborne Electronic Hardware See CS-ETSO, Subpart A, paragraph 2.3. 3.2 Specific 3.2.1 Failure Condition Classification See CS-ETSO, Subpart A, paragraph 2.4. Failure of the function defined in paragraph 3.1.1 resulting in false warnings or an unannunciated loss of function is a major failure condition. A loss of the function defined in paragraph 3.1.1 is a minor failure condition. 3.2.2 Documentation The manufacturer of the offshore HTAWS shall document in its declaration of design and performance (DDP), installation and operator manuals the transition speed between the two-mode 4A alerts, and, when the corresponding modes are implemented, the intended helicopter type for which the mode 7A and/or 7B alerts have been designed. **4 Marking** 4.1 General See CS-ETSO, Subpart A, paragraph 1.2. 4.2 Specific None. **5 Availability of Referenced Documents** See CS-ETSO, Subpart A, paragraph 3. [Amdt ETSO/17] --- [[1]](#_ftnref1) The published date represents the date when the consolidated version of the EAR book was generated. [[2]](#_ftnref2) Euro-Lex, Important Legal Notice: <http://eur-lex.europa.eu/content/legal-notice/legal-notice.html>. [[3]](#_ftnref3) This is the main applicability date defined in the ED Decision. However, the decision allowed that this CS was not applied to applications received until 31 December 2012, if so requested by the applicant and providing that in such a case the applicant could demonstrate that the process of development of the relevant part or appliance started before the entry into force of the ED Decision (5 July 2012), in accordance with the specifications applicable at that time. [[4]](#_ftnref4) This is the main applicability date defined in the ED Decision. However, the decision allowed that this CS was not applied to applications received until 31 December 2013, if so requested by the applicant and providing that in such a case the applicant could demonstrate that the process of development of the relevant part or appliance started before the entry into force of the ED Decision (15 July 2013), in accordance with the specifications applicable at that time. [[5]](#_ftnref5) This is the main applicability date defined in the ED Decision. However, the decision allowed that this CS was not applied to applications received before 1 July 2018, if so requested by the applicant and providing that in such a case the applicant could demonstrate that the process of development of the relevant part or appliance started before the entry into force of the ED Decision (20 February 2018), in accordance with the specifications applicable at that time. [[6]](#_ftnref6) This is the main applicability date defined in the ED Decision. However, this decision shall not apply to applications received by EASA 6 months after the date of entry into force of this Decision, if so requested by the applicant, and provided that in such a case the applicant can demonstrate that the process of development of the relevant part or appliance started before the date of entry into force of this decision and is in accordance with the specifications applicable at that time. [[7]](#_ftnref7) This is the main applicability date defined in the ED Decision. However, this decision shall not apply to applications received by EASA 6 months after the date of entry into force of this Decision, if so requested by the applicant, and provided that in such a case the applicant can demonstrate that the process of development of the relevant part or appliance started before the date of entry into force of this decision and is in accordance with the specifications applicable at that time. [[8]](#_ftnref8) Refer to ED Decision 2020/010/R (<https://www.easa.europa.eu/document-library/agency-decisions>). [[9]](#_ftnref9) Refer to ED Decision 2020/010/R (<https://www.easa.europa.eu/document-library/agency-decisions>). [[10]](#_ftnref10) NOTE: Tests that require human subjects or a child test dummy shall use time-encoded video [[11]](#_ftnref11) Copies of this paper may be obtained from the RTCA Secretariat, ‘Room 1072, T-5 Building 16th and Constitution Avenue, N.W., Washington, D.C., at a cost of 75 cents per copy. [[12]](#_ftnref12) [https://ics-cert.us-cert.gov/sites/default/files/documents/Improving\_the\_Operation\_and\_Development\_of\_Global\_Positioning\_System\_(GPS)\_Equipment\_Used\_by\_Critical\_Infrastructure\_S508C.pdf](https://ics-cert.us-cert.gov/sites/default/files/documents/Improving_the_Operation_and_Development_of_Global_Positioning_System_%28GPS%29_Equipment_Used_by_Critical_Infrastructure_S508C.pdf). [[13]](#_ftnref13) [https://ics-cert.us-cert.gov/sites/default/files/documents/Improving\_the\_Operation\_and\_Development\_of\_Global\_Positioning\_System\_(GPS)\_Equipment\_Used\_by\_Critical\_Infrastructure\_S508C.pdf](https://ics-cert.us-cert.gov/sites/default/files/documents/Improving_the_Operation_and_Development_of_Global_Positioning_System_%28GPS%29_Equipment_Used_by_Critical_Infrastructure_S508C.pdf) [[14]](#_ftnref14) <https://www.easa.europa.eu/documents/public-consultations/proposed-special-condition-%E2%80%98non-rechargeable-lithium-battery> [[15]](#_ftnref15) <https://www.easa.europa.eu/documents/public-consultations/proposed-special-condition-%E2%80%98non-rechargeable-lithium-battery> [[16]](#_ftnref16) Functional ETSO standard: any ETSO standard of CS-ETSO describing an aircraft function, i.e. typically the majority of all ETSO standards except ETSO-C153a and this ETSO-C214. [[17]](#_ftnref17) ‘F-ETSO equipment’ is the integrated equipment for which the applicant is seeking an ETSO standard approval, using ETSO-C153a platform(s)/module(s). [[18]](#_ftnref18) The term „medium“ is used herein to mean anominal operating pressure of 1,500 p.s.i. or less. [[19]](#_ftnref19) The term „high“ pressure means a nominal operating pressure greater than 1,500 p-s.i. and up to and including 3,000 p.s.i. [[20]](#_ftnref20) A suitable test fluid is one which is representative of that to be used with the applicable hose assembly in civil transport category aircraft operation. [[21]](#_ftnref21) https://ics-cert.us-cert.gov/sites/default/files/documents/Improving\_the\_Operation\_and\_Development\_of\_Global\_Positioning\_System\_(GPS)\_Equipment\_Used\_by\_Critical\_Infrastructure\_S508C.pdf [[22]](#_ftnref22) [https://us-cert.cisa.gov/sites/default/files/documents/Improving\_the\_Operation\_and\_Development\_of\_Global\_Positioning\_System\_(GPS)\_Equipment\_Used\_by\_Critical\_Infrastructure\_S508C.pdf](https://us-cert.cisa.gov/sites/default/files/documents/Improving_the_Operation_and_Development_of_Global_Positioning_System_%28GPS%29_Equipment_Used_by_Critical_Infrastructure_S508C.pdf) [[23]](#_ftnref23) Regulation (EC) No 1907/2006 of the European Parliament and of the Council of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), establishing a European Chemicals Agency, amending Directive 1999/45/EC and repealing Council Regulation (EEC) No 793/93 and Commission Regulation (EC) No 1488/94 as well as Council Directive 76/769/EEC and Commission Directives 91/155/EEC, 93/67/EEC, 93/105/EC and 2000/21/EC (OJ L 396, 30.12.2006, p. 1).