diff --git a/libraries/AP_RTC/AP_RTC.cpp b/libraries/AP_RTC/AP_RTC.cpp
index 809cf371fd..f93f129d23 100644
--- a/libraries/AP_RTC/AP_RTC.cpp
+++ b/libraries/AP_RTC/AP_RTC.cpp
@@ -205,49 +205,6 @@ uint32_t AP_RTC::get_time_utc(int32_t hour, int32_t min, int32_t sec, int32_t ms
     return static_cast<uint32_t>(total_delay_ms);
 }
 
-
-/*
-  mktime replacement from Samba
- */
-time_t ap_mktime(const struct tm *t)
-{
-    time_t epoch = 0;
-    int n;
-    int mon [] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }, y, m, i;
-    const unsigned MINUTE = 60;
-    const unsigned HOUR = 60*MINUTE;
-    const unsigned DAY = 24*HOUR;
-    const unsigned YEAR = 365*DAY;
-
-    if (t->tm_year < 70) {
-        return (time_t)-1;
-    }
-
-    n = t->tm_year + 1900 - 1;
-    epoch = (t->tm_year - 70) * YEAR +
-            ((n / 4 - n / 100 + n / 400) - (1969 / 4 - 1969 / 100 + 1969 / 400)) * DAY;
-
-    y = t->tm_year + 1900;
-    m = 0;
-
-    for (i = 0; i < t->tm_mon; i++) {
-        epoch += mon [m] * DAY;
-        if (m == 1 && y % 4 == 0 && (y % 100 != 0 || y % 400 == 0)) {
-            epoch += DAY;
-        }
-
-        if (++m > 11) {
-            m = 0;
-            y++;
-        }
-    }
-
-    epoch += (t->tm_mday - 1) * DAY;
-    epoch += t->tm_hour * HOUR + t->tm_min * MINUTE + t->tm_sec;
-
-    return epoch;
-}
-
 // singleton instance
 AP_RTC *AP_RTC::_singleton;