1967-03: The longest  flight

From the  Aviator's Flight Logbook of March 1967:   Lots of activity this month, which marks about the halfway point in the year long RA-5C RAN (reconnaissance attack navigator) flight syllabus.  By this time we (LCDR Gene Campbell, pilot, and self)  had completed navigation, bombing, and reconnaissance training flights around the southeast US.  A typical flight would simulate a low altitude penetration around the state, then practice bombing at Lake George.  Low altitude high speed radar navigation is definitely a skill that needs practice, but relating radar imagery to tactical maps is generally pretty straightforward, especially if there's land water contrast.  

Today's flight was something different: a contour mapping flight into the mountains northeast of Atlanta (see map).  Contour mapping is an advanced radar mode that displays the terrain above a set height, regardless of aircraft altitude.  The idea is to show the crew how to navigate the aircraft while flying at a more or less constant altitude. This is related to the more conventional terrain avoidance flight, in which the aircraft flies a predetermined course and avoids terrain by changing altitude.

Navigating in contour mapping mode proved to be very challenging.  The radar imagery was critically dependent on the selected mapping height, in very non-intuitive way.  Several times during the flight we had to pop up above the mountains to take a quick update of our position using conventional radar mapping.  

Because of the challenging nature of these flights, crews were split up and teamed with instructor pilots and navigators.  I was fortunate in drawing LCDR Jerry Chapdelaine for this flight.  While all RA-5C pilots were highly qualified, Jerry was exceptionally so, being a Test Pilot School graduate in addition to extensive fleet experience in both the A-5A and RA-5C, for which he was a qualified Landing Signal Officer ("paddles").  

He got to use that expertise on this flight. What with the unplanned deviations from the flight plan, we spent a lot more time airborne, a total of 3.1 hours. This would turn out to be my longest unrefuelled flight in the Vigilante. The RA-5C burns 8000 lb/hr of fuel at low altitude and 6000 high, and that the total fuel capacity is 23,000 lb.  Fortunately the weather was not a factor so we didn't need to expend the extra fuel involved in an instrument approach.  As it was, it was a pretty close thing.   Best part of it was that Jerry was the soul of stoic Naval Aviator calmness throughout. I was calm as well, since I wasn't aware of our fuel problem until we landed!

Ref:

http://www.boeing.com/history/products/a3j-1-a-5-ra-5c-vigilante.page

Next log entry: 1967-04: FCLP