DC-7C Starring Role: Airliner in Distress Over Water

Accident description

Narrative:
Flight 1-11 arrived at Okinawa at 16:25 following a flight from New York via Seattle, Anchorage Cold Bay and Tokyo. The flight departed Okinawa at 17:12 GMT for the last leg of the flight to Manila. Two hours after takeoff, at 03:15 local time, the no. 2 engine experienced a power loss, indicated by a drop in mean effective pressure and manifold pressure. Believing the difficulty was carburetor icing the crew tried to correct the problem. The problems persisted and the captain then noticed the oil-out temperature for no. 2 engine rising. Attempts to feather the no. 2 propeller failed and the flight was cleared to descend from FL180 to FL100. An emergency was declared at 03:40. While at 9000 feet it was attempted to actuate the firewall shutoff valve, depriving the engine of lubricant and thus to stop the (no. 2) engine rotation. The propeller then wrenched free of the engine and struck the fuselage, slashing a 15inch hole. There was a continuous fire warning from the no. 2 engine and a fire on the wing was reported to Manila at 04.20. A 3000-feet/min descent from 9000 feet was made. At 1000 feet descent rate was decreased to 100-200 feet/min and a ditching was carried out. Upon final contact with the water, the aft end of the fuselage broke free at the rear of the pressure bulkhead. At the same time the right wing as torn free and the engines separated. The wing floated for 3 hours, temporarily serving as a life raft for several passengers. The remainder of the fuselage sank some 8 or 10 minutes after impact. All occupants were rescued by US Coast Guard and US Navy aircraft 4-6 hours after the accident.

PROBABLE CAUSE: "The accident was due to the internal failure of No.2 engine, which resulted in oil contamination, loss of oil supply, subsequent loss of the No.2 propeller assembly, and fire in flight, which necessitated a ditching." 

Reference a - (With permission)

P5M-1 Starring Role: Pick Up Survivors

“…. Search and Rescue (SAR) operations had begun as soon as Capt. Rail reported losing the #2 prop. Capt. I.G. Cockroft USN (Ret) then Co of VP-40, recalls being called at about 3:30 am by his duty officer with the report: “We have a SAR alert sir, a Northwest plane out of Tokyo reporting losing the number 2 prop…”Skipper, I’ve just launched the SAR in 5 Boat…The DC-7 is on fire and they are going to ditch…All the stops were out now. The Coast Guard and the Navy have SAR planes airborne within 5 minutes of the MAYDAY WE ARE DITCHING call from the Northwest aircraft.

At about 0730 hours, LTJG Hite got a message through on the fleet common high frequency radio as he was out of voice range. ‘Sighted three rafts in the water, CG landed along side, I am landing now.’ Four minutes later another message from 5 Boat. ‘Sea state 3 all OK, taking on survivors. 

[5 Boat and the CG SA-16 taxied to a lagoon about 20 miles distant – the SA-16 could not take off because of the sea state. 4 Boat, launched earlier, showed up to take the SA-16 survivors; 4 and 5 boats proceeded to Sangley.]

“I landed, proceeded to off load 23 survivors to 4 Boat and took off for Sangley. Fifty minutes later we were on the buoy…5 Boat was right behind. The 42 survivors and one fatality carried by the Marlins were immediately taken to the station hospital.”

The Airplanes

Martin P5M Marlin

Although it was not known in 1960, the P5M would be the navy’s last ‘P-Boat.’ Great things were expected of the so-called ‘Seaplane Striking Force’ centered on the P6M Seamaster, with supporting roles played by the Convair R5Y and Sea Dart. Also in a supporting role were specialized tenders (including submarines) intended to forward base a nuclear strike force without having to ask basing permission as SAC did of foreign governments. But it all went for naught when Martin in simple terms could not get the P6M to work. For details, see reference c.

The Marlin was initially the World War II R-3350- powered PBM-6, first cancelled in favor of the R-2800-powered PBM-5 and later resuscitated post-war with a new hull and massive single vertical tail. 277 were built in two principal versions. This project replicates the P5M-1; the –2 introduced a modified hull form up forward, and a T-tail. Over the period 1952-1967 VP-40 operated 84 different P5Ms and was the last P-Boat squadron to be decommissioned in 1967. 

DC-7C                       

The ultimate Douglas Propliner and the last version of the DC-7. Douglas had not wanted to do the DC-7 but was pressured into it by American Airlines which wanted a westbound transcontinental competitor to the speedy L-1049 Constellation operated by TWA. To get the speed, the DC-7 introduced the turbo-compound Wright R-3350. Two versions, slightly stretched DC-6s, were followed by the –7C with extended wing inner sections carrying more fuel and yet another fuselage extension. It is interesting to note that all the Douglas four-engine propliners used the same wing planform from the DC-4 through the DC-7B. The –7C’s vertical tail was increased in height by about two feet. Northwest operated seventeen DC-7Cs.

Revell Box Scale DC-7C      

This is a 1957 kit that has been in and out of release for half a century. To my eye the major components of the kit look right and with that weird scale many modeler agonies have been avoided re accuracy. The long-range ‘saddle tanks’ introduced in some DC-7B models are there along with D/F footballs, and ILS antenna and couple of others that may represent whips. The cockpit fenestration was open in the original release; plastic sheet is provided to represent perspex if desired. The cabin windows are recessed. There is a limited set of raised rivets professionally done if one accepts such things, which I do. There is a lot of flash and plenty of injection pin marks.

I decided to use weights in the nose and did so with flattened fishing sinkers held in place first with CA and then white glue. Most DC-7Cs had a slightly elongated nose containing weather radar. The kit does not have this nose, but the NWA DC-7Cs did, so I lightly sanded the nose of both fuselage halves to make a slot to receive a piece of scrap plastic sheet. Glued up the halves a bit at a time; removed the upper locating pins to avoid ‘steps’ at the join (unsuccessfully as it turned out). The radar nose was crafted using putty on the plastic base and shaping by eye with reference to photographs. Sink marks along the top joint were dealt with using putty. The main entrance door is provided as a separate part; the baggage compartment door and crew entrance door are molded in; a little deep but not as bad as early Minicraft airliner kits. The horizontal tail surfaces were saved for later.   

Near perfect fit of the upper/lower halves. An indicator perhaps of molding limitations of the time is the provision of separate wing tips. The nacelles forward of the wings are two-piece affairs with the correct representation of the exhausts (bored out by me) coming from the Power Recovery Turbines that made the engines ‘compound.’ The oil cooler and carb air intakes are molded solid; I bored them out a bit for visual depth. The cowls are separate with virtually no engine detail. This was not a problem for me, since little of the cowl opening is visible once the props are installed. Not much left to tell. The landing gear representation is a bit crude, but the main wheels serve to cover up some of this. Wheel well doors are a bit thick but appear to be accurate in outline; I elected not to replace them. The various antennas are good representations if a bit oversize. Given the good joins, the wings were painted and decaled prior to joining to the fuselage. The horizontal tail is not as clean, so painting was deferred until after the joins, which in turn was deferred awaiting fuselage painting and decaling.

N292’s basic paint scheme was the standard white- over-NMF that had become common for most pressurized airliners of the time. I used Krylon rattle-can gloss white over the entire airframe. I had previously scaled up a copy of Flying Colors NWA DC-6 decals to match the box scale and the enlarged tail of the DC-7C.

So, the fuselage sequence was:

Overall white. Blue cheat line above the Cabin Windows from the homemade decal sheet. Alcad NMF Polished Aluminum for the lower fuselage. ‘Northwest’ from the Flying Colors decal sheet on tail and nose, plus little details (door outlines, etc.). ‘N292’ serial from generic white letter/numeral sheet; American Flags on vertical tail and ‘DC-7C’ from the homemade decals. Red tail from the homemade decal sheet.

Wing sequence:

Overall white. Alcad Polished Aluminum. MM Light Gray for the areas around and aft of the nacelles. American flags on wings from the homemade decal sheet. ‘N292’ serial from generic black letter/numeral sheet

 Recalling N292 was operating in the Pacific while Chinese shoot-downs and attacks on commercial airliners were occasionally in the news of the times, NWA aircraft substituted a large American Flag on the upper port wing/lower starboard wing (and in lieu of the traditional big red “NWA.”  At least that’s my read on this marking. The flags are also on the fin.

This kit is not up to 1980 standards, much less today, but it is the only injection-molded kit of this airplane in any scale. It has the flash and injection pin marks of older kits but remains a relatively easy build. There are many marking options for 1^st Tier operators of this airplane. I’ve already done a BOAC version through the ‘scale-up decals’ method. The kit provides Pan Am decals, and apparently there are others in earlier re-issues. Recommended for propliner buffs.  

Hasegawa P5M Marlin 

This kit has been around for a while. I got mine through private purchase; everything was in the box except decals but, given (per the instructions) the decals were for French P5Ms, little was lost except some maintenance markings.

The kit represents the P5M-2 (later SP-5B). There are substantial visual differences between the –2 and the –1 that did the amazing rescue. These are the vertical tail and the chine line from the radar aft to about the location of the beaching gear.

 Vertical Tail      The horizontal stab must be moved from the top of the T-tail down level with the top of the fuselage (or thereabouts). The vertical stab must be replaced. Fortunately the Marlin was a contemporary with another Martin product, the P4M Mercator, and they both shared the same tail. Drawings of the latter exist (Reference c), and were used to scratch- build a new tail from laminated 30 thou plastic sheet.

The kit tail was sawn off. The horizontal tail on the –1 was a tad wider than the –2 so the kit part was sawn in two and brass tubing was used to rejoin them and establish the correct width. This part was then glued to the top of the fuselage, into a cutout sanded out to take the piece’s lower surface airfoil shape. A ‘stub’ had been left in the scratch vertical tail and this anchored this piece between the two halves of the horizontal tail. (Editor's note: the small picture is the full size that was sent in)

The fin leading edge is differently shaped than that of the Mercator – this was corrected with pieces of plastic sheet, much putty, and a piece of the kit leading edge.

The –1 Magnetic Anomaly Detector was located on the top of the fin (it extended aft of the T-tail in the –2) in a little pod on top of a short pylon. The pod was shaped from wooden dowel and the pylon from plastic sheet with a wire mounting. Little wire circles replicate antennas visible in photos were attached to the forward end of the pod (I have no idea what they were for).

 Chine Line       

I stared at many photos trying to decide how to do this modification and came up with many schemes. I finally began by rough sawing off the under fuselage pieces along the existing chine line up to the bottom of the radome. There are two big visual differences; (1) the –2 chine terminates a distance under the radome and the –1 a bit higher and (2) the ‘secondary chine of the –2 does not exist on the –1. Much sanding and grinding removed this latter feature. Removing material aft of the radome and relocating the cutaway pieces altered the chine line. The reconstruction was based on a new centerline for this part of the hull, established using plastic sheet set into a notch at the after end of the cutout.

Everything Else This kit is BIG but comparatively simple. The fit ranges from excellent to so-so. The latter issue results in the elimination of some of the very petite raised rivet detail. Postionable wing flaps and cowl flaps are provided, and I elected to use them ‘down’ and ‘open.’ respectively. Mounting slots for the wing pontoons V-struts are provide in the pontoons, but locating holes on the wing are not so these had to be done after figuring out the assembly’s angular relationship to the lower wing. There are little ‘steps’ to be dealt with in various assemblies, notably the radome and the upper fuselage. The outer wing/inner wing joins are tight, so I did not glue them up, making for easier storage and transport

By 1960 overall paint for VP aircraft had evolved from the post-war Glossy Sea Blue, to overall Glossy Seaplane Gray, to a Gloss White upper fuselage over the Seaplane Gray. As with the DC-7C things began with a rattle-can white.

Masking was followed by air brushing Seaplane Gray. Further masking allowed the deicer boots to be painted black.. The propeller-warning stripe was also masked and painted in red. From photos the big radome was done in a variety of styles; I elected the all-white style matching the fuselage.

Decaling was relatively simple – generic national insignia and numbers and letters in black and white, plus some ‘danger’ arrows from a 1:72 Superscale sheet for aircraft of the period. VP-40 aircraft were coded “QE” on the vertical stab and the upper right and lower left wing. The ‘last four’ of the BuNo were under the “QE” on the vertical tail. “4” in black on the nose and in white on the wings. About ½ pint of Future (or so it seemed) was applied overall.

It is unlikely that there ever be another kit of the Marlin-series in this scale, although Minicraft may do it 1:144 one day. The kit has gone in and out of release (currently ‘out’ I believe). There are inevitably fit issues with the big wing-fuselage joint, but not past redemption. Detailing of parts like the beaching gear and engines and cowl are very good of the time, and now for that matter. I recommend this big model, but I’m a fan of P-Boats.

 Epilogue – The last seaplane tender

VP-40 SP-5Bs (aka, P5M-2s) were out and about in the South China Sea in 1966-67, based on USS Currituck (AV-7) in Cam Ranh Bay; I remember seeing them on their Market Time patrols. In the summer of 1967 I was spending time in the Inactive Ship Facility inside the Mare Island Naval Shipyard as my current ship went through the decommissioning process. Currituck was there as well on her way to the reserve fleet; VP-40’s Marlins were by that time lined up in forlorn rows at NAS North Island, never to fly again.  Currituck was not as far in the decommissioning process as my ship and was still feeding aboard, so my ship’s crew messed aboard her. Wooden decks, and those enormous seaplane cranes – never to be seen again.

AV-7 was decommissioned for the last time on 31 October 1967, stricken for disposal on 1 April 1972, and from Naval Records on 1 January 1972.  She was dismantled at Learner Shipyard, Oakland, CA in June 1972. 

1. Accident description. The Aviation Safety Network Website. http://aviation-safety.net/database/record.php?id=19600714-0
2. Hoffman, R (2007).  The Martin P5M Patrol Seaplane. Simi Valley, CA: Ginter Publications
3. Ginter, S. (1996). Martin P4M-1/-1Q Mercator. Simi Valley, CA: Ginter Publications
4. Trimble, T. (2005). Attack from the Sea; A History of the U.S. Navy’s Seaplane Striking Force.  Annapolis, MD: Naval Institute Press

Joe Lyons

February 2009

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