FLIGHT SIX – FLAPPING AROUND IN A SEASPRITE

At the end of the Test Pilots’ course at ETPS there used to be an final exercise called ‘Preview’, other flight test schools do similar things but called different names and perhaps with a different focus.??For the staff at the school it is a perpetual battle to find unique aircraft for the students to fly with the right approvals and precursory arrangements.??For our course, a rather cosy 4 students by the time we got to this point, only two helicopters were required and we were able to make use of the excellent relationship with the United States Navy (and its school) to fix suitable arrangements.??Whilst our Australian had a meaty attack helicopter to focus on (the AH-1W Cobra) my Dutch colleague and I were faced with what we thought was a less stellar result, the SH-2G Sea Sprite an aircraft the US Navy was about to retire (this was 1999).

However out immediate disappointment was allayed somewhat when we received the aircraft NATOPS manual (Flight Manual in civvy speak) and saw we were dealing with a very different philosophy in terms of the rotor flight control system, but more of that later.??The role we were given for the aircraft was as a frigate helicopter which needed to operate in the Middle East all year round so performance was clearly going to be a key focus for us.??Luckily when we arrived at Naval Air Station Joint Reserve Base Willow Grove, in Philadelphia, we were greeted??with the news that because the Squadron would be closing flight hours were not a problem and we should plan for lots of flying (normally Preview teams struggle to get more than 6-8 hours, we got 12!).??So we merrily went through our test plans, flew day and night and had an epic trip to Kaman Helicopters (previously reported on during Flight 2).??We wanted to finish on a high and our instructor was keen for us to see more of the East Coast so we set on a plan to fly our level flight performance tests, in one day, around the low level helicopter routes through New York and Washington D.C..??

Now you might think that’s a rather large ask but a quick look at the map and one can quickly see that Philadelphia is smack back in the middle of the two cities, around 80 miles to New York and 120 miles to Washington D.C..??So it meant a total flight time of around 4 hours between the two of us with me taking the first leg North to New York and my Dutch colleague taking the second leg, post refuel at Willow Grove, South to Washington D.C..??We had some test points to collect on the way but anyone who knows anything about level flight helicopter performance testing will tell you it’s a little more complex than you first think and the planning is the important part.??But hey, we were off on an epic trip and the weather was equally fantastic with clear autumn skies and light winds!

By this point in our two weeks in Philadelphia we were well used to the aircraft, the airfield and the area and were soon on our way.??Although an analogue 1960s aircraft at heart the introduction of the T700 engines and a reasonable Flight Management System (FMS) meant that the it was easy to start and to set up our flight plan for the journey ahead.??The flap control system on the main rotor blades, whilst at first treated with trepidation really had given us no issues during testing (apart from some interest cross coupling during recovery from autorotation) and the system provided for light and precise control inputs when flying around.??The aircraft was nimble in the hover for a non-rigid rotor head system and seemed to provide a great platform for deck operations.

Flying up the East Coast one gets to appreciate how densely populated this part of the USA is and we soon saw the skyscrapers of New York on the horizon.??Our instructor tour guide was keen to point out all the salient landmarks and we really weren’t doing any flight testing at this point, such was the view.??The Sea Sprites’ flight controls and autopilot were doing much of the hard work for me which was a test finding all on its own.??Once we had circled Manhattan clockwise it was time to route back South??and get some data.

Here was the rub, of course, we hadn’t really done enough study of the performance charts in the NATOPS manual (Section 11) to know what data to collect or what would be the best speeds and heights to use.??So we did what most would do in that situation and picked key speeds and heights which we knew we could get and hoped we could make the data fit when it came to writing the report (in Preview you were required to do spot checks of the flight manual data).??Also, because we had refuel times to make and were limited with the altitudes we could use, we were constrained a little in how much we could actually collect.

So we carried on back to Willow grove, where we topped up the fuel tanks and changed pilots, with it now my turn to sit in the back and take down the data.??The rear crew seat, for the sonics crewman, has its own window so I was still able to enjoy the view as we followed I-95 down past Baltimore.??Joining??the helicopter route around Leesburg to fly South East down the Potomac towards Alexandria, passing CIA headquarters and the National Mall before leaving the route close to Andrews AFB.???I’m not even sure the routes can be flown so easily now but it was certainly an epic journey at less than 500 feet above the river, before we turned North and made our way back to Willow Grove.??We should have collected more data on the way back but we had exhausted that repertoire earlier so it was a very mellow journey since it was out last flight in the aircraft prior to getting on with the report.

A Preview report is a major written report and is typically over 150 pages providing a comprehensive overview of the technical and potential operational capability of an aircraft from a limited amount of flying.??To deliver a successful report the student needs to have collected and collated a myriad of different data elements from cockpit field of view photographs all the way through to detailed performance data.??So it was that we started getting our data together and realising that we really had missed the point of the performance flights.??Hindsight is not particularly useful at this stage so we had to make sure that we could report on what we had seen in the most technically relevant way possible albeit with a degree of choosing the performance elements we should use rather than those we should have checked.

Of course the lesson here is about preparation, but that would be a little unfair on us since the performance trips we had done were well in excess of what most students would hope to get on Preview.??What we had done however is discovered that far from being an aircraft ready for retirement (the aircraft had only been in service 15 years) the SH-2G Sea Sprite was a powerful and responsive helicopter with an impressive range and endurance even when operating in hot and high conditions (if the NATOPS manual was correct).??Out instructor told us he once had an engine failure in the Red Sea on take-off and that the power reserve was such he didn’t even exceed the limits on the good engine.??I, for one, would like to fly it again (any helicopter the pilot can open the door in flight is great for me).