Ref T385, OBS aircraft callsign

* in CAirspaceMonitor::onIcaoCodesReceived we know we deal with aircraft only and explicitly deal with it
* in other cases we can not tell if we deal with aircraft/ATC callsign for sure, we ignore invalid callsigns

src/blackmisc/aviation/callsign.cpp

@@ -87,6 +87,11 @@ namespace BlackMisc
             return m_callsign.endsWith("SUP");
         }
 
+        bool CCallsign::isCopilotCallsign() const
+        {
+            return (this->getTypeHint() == Aircraft) && this->isObserverCallsign();
+        }
+
         QString CCallsign::getIcaoCode() const
         {
             if (this->isAtcCallsign())
@@ -96,7 +101,7 @@ namespace BlackMisc
                     return m_callsign.left(4).toUpper();
                 }
             }
-            return "";
+            return QStringLiteral("");
         }
 
         bool CCallsign::isAtcAlikeCallsign() const
@@ -108,7 +113,6 @@ namespace BlackMisc
 
         bool CCallsign::isObserverCallsign() const
         {
-            if (this->getTypeHint() == Aircraft) { return false; }
             return m_callsignAsSet.endsWith("_OBS", Qt::CaseInsensitive);
         }
 

src/blackmisc/aviation/callsign.h

@@ -84,6 +84,9 @@ namespace BlackMisc
             //! Supervisor?
             bool isSupervisorCallsign() const;
 
+            //! Pilot OBS callsign, normally a co-pilot
+            bool isCopilotCallsign() const;
+
             //! Get callsign (normalized)
             const QString &asString() const { return m_callsign; }