Title: CPDLC - Reserved Messaged Elements PDR Reference: 97100037 Originator Reference: reservd SARPs Document Reference: CPDLC SARPs, Sections 2.3.4.2.1 and Table 2.3.7-25 Status: ADOPTED PDR Revision date: 29/10/97 (SUBMITTED -> RESOLVED) PDR Submission Date: 24/10/97 Submitting State/Organization: FAA Submitting Author Name: Hamelink,J Submitting Author E-mail Address: jhamelin@adsystech.com Submitting Author Supplemental Contact Information: Tel: 1 301 589 3434 x114 Fax: 1 301 589 9254 SARPs Date: IV1.1, March 97 SARPs Language: English Summary of Defect: The ADSP Manual is being aligned to existing ICAO annexes. In this process is was found that the message elements "IMMEDIATELY STOP CLIMB" and "IMMEDIATELY STOP DESCENT" are operationally redundant with the "STOP CLIMB" and "STOP DESCENT" message elements. These two message elements will be considered reserved in the initial ADS Manual message set (Same as UM33 and UM178). Other than prohibiting these message elements from being sent there is no affect on "bits on the wire". The CPDLC SARPs should be aligned with the ADS Manual for the message set. Assigned SME: Sub-Volume II SME Proposed SARPs amendment: 1. Change the uplink message elements UM40 and DM41 to Reserved in section 2.3.4.2.1 from: -- IMMEDIATELY STOP CLIMB AT [level] Urg(D)/Alr(H)/Resp(W/U) uM40Level [40] Level, -- IMMEDIATELY STOP DESCENT AT [level] Urg(D)/Alr(H)/Resp(W/U) uM41Level [41] Level, To: -- Reserved Urg(L)/Alr(L)/Resp(Y) uM40NULL [40] NULL, -- Reserved Urg(L)/Alr(L)/Resp(Y) uM41NULL [41] NULL, (the word "Reserved" is italicized) 2. Change section 2.3.7.3.10.1 from: The CPDLC-ground-user shall be prohibited from sending any CPDLC message containing either the uplink message element 33 or 178. To: The CPDLC-ground-user shall be prohibited from sending any CPDLC message containing the uplink message element 33, 40, 41, or 178. 3. Change section 2.3.7.3.11.6.1 from: If the CPDLC-air-user receives a message containing either the uplink message element identifier 33 or 178 the CPDLC-air-user shall invoke the CPDLC-message request with the ERROR [errorinformation] message element with the [invalidMessageElement] value as the CPDLC Message parameter, and disregard the received message. To: If the CPDLC-air-user receives a message containing the uplink message element identifier 33, 40, 41, or 178 the CPDLC-air-user shall invoke the CPDLC-message request with the ERROR [errorinformation] message element with the [invalidMessageElement] value as the CPDLC Message parameter, and disregard the received message. 4. Change table 2.3.7-25 in section 2.3.7 from: Message Intent/Use Message Element URG ALRT RESP 40 Urgent instruction to IMMEDIATELY STOP CLIMB D H W/U immediately stop a climb AT [level] once the specified level is reached. 41 Urgent instruction to IMMEDIATELY STOP D H W/U immediately stop a DESCENT AT [level] descent once the specified level is reached. to: Message Intent/Use Message Element URG ALRT RESP 40 Reserved. L L Y 41 Reserved. L L Y The word "Reserved" is italicized. SME Recommendation to CCB: - CCB Decision: CCB-3: RESOLVED