diff --git a/libraries/AP_Logger/AP_Logger.h b/libraries/AP_Logger/AP_Logger.h
index 74b9cf1cd4..7452613477 100644
--- a/libraries/AP_Logger/AP_Logger.h
+++ b/libraries/AP_Logger/AP_Logger.h
@@ -448,6 +448,9 @@ private:
 
     bool _armed;
 
+    // state to help us not log unneccesary RCIN values:
+    bool seen_nonzero_rcin15_or_rcin16;
+
     void Write_Baro_instance(uint64_t time_us, uint8_t baro_instance, enum LogMessages type);
     void Write_IMU_instance(uint64_t time_us,
                                 uint8_t imu_instance,
diff --git a/libraries/AP_Logger/LogFile.cpp b/libraries/AP_Logger/LogFile.cpp
index f355d18fa6..678d5dd4d3 100644
--- a/libraries/AP_Logger/LogFile.cpp
+++ b/libraries/AP_Logger/LogFile.cpp
@@ -185,7 +185,7 @@ void AP_Logger::Write_GPS(uint8_t i, uint64_t time_us)
 // Write an RCIN packet
 void AP_Logger::Write_RCIN(void)
 {
-    uint16_t values[14] = {};
+    uint16_t values[16] = {};
     rc().get_radio_in(values, ARRAY_SIZE(values));
     const struct log_RCIN pkt{
         LOG_PACKET_HEADER_INIT(LOG_RCIN_MSG),
@@ -206,6 +206,23 @@ void AP_Logger::Write_RCIN(void)
         chan14        : values[13]
     };
     WriteBlock(&pkt, sizeof(pkt));
+
+    // don't waste logging bandwidth if we haven't seen non-zero
+    // channels 15/16:
+    if (!seen_nonzero_rcin15_or_rcin16) {
+        if (!values[14] && !values[15]) {
+            return;
+        }
+        seen_nonzero_rcin15_or_rcin16 = true;
+    }
+
+    const struct log_RCIN2 pkt2{
+        LOG_PACKET_HEADER_INIT(LOG_RCIN2_MSG),
+        time_us       : AP_HAL::micros64(),
+        chan15         : values[14],
+        chan16         : values[15]
+    };
+    WriteBlock(&pkt2, sizeof(pkt2));
 }
 
 // Write an SERVO packet
diff --git a/libraries/AP_Logger/LogStructure.h b/libraries/AP_Logger/LogStructure.h
index 084fd2637d..f74c4c4321 100644
--- a/libraries/AP_Logger/LogStructure.h
+++ b/libraries/AP_Logger/LogStructure.h
@@ -304,6 +304,13 @@ struct PACKED log_RCIN {
     uint16_t chan14;
 };
 
+struct PACKED log_RCIN2 {
+    LOG_PACKET_HEADER;
+    uint64_t time_us;
+    uint16_t chan15;
+    uint16_t chan16;
+};
+
 struct PACKED log_RCOUT {
     LOG_PACKET_HEADER;
     uint64_t time_us;
@@ -2450,6 +2457,8 @@ struct PACKED log_Winch {
       "MSG",  "QZ",     "TimeUS,Message", "s-", "F-"}, \
     { LOG_RCIN_MSG, sizeof(log_RCIN), \
       "RCIN",  "QHHHHHHHHHHHHHH",     "TimeUS,C1,C2,C3,C4,C5,C6,C7,C8,C9,C10,C11,C12,C13,C14", "sYYYYYYYYYYYYYY", "F--------------" }, \
+    { LOG_RCIN2_MSG, sizeof(log_RCIN2), \
+      "RCI2",  "QHH",     "TimeUS,C15,C16", "sYY", "F--" }, \
     { LOG_RCOUT_MSG, sizeof(log_RCOUT), \
       "RCOU",  "QHHHHHHHHHHHHHH",     "TimeUS,C1,C2,C3,C4,C5,C6,C7,C8,C9,C10,C11,C12,C13,C14", "sYYYYYYYYYYYYYY", "F--------------"  }, \
     { LOG_RSSI_MSG, sizeof(log_RSSI), \
@@ -2693,6 +2702,7 @@ enum LogMessages : uint8_t {
     LOG_IMU_MSG,
     LOG_MESSAGE_MSG,
     LOG_RCIN_MSG,
+    LOG_RCIN2_MSG,
     LOG_RCOUT_MSG,
     LOG_RSSI_MSG,
     LOG_IMU2_MSG,