Mission Endeavor Project Overview

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Mission Endeavor is the culmination of a three year long collaborative effort by Air/Sea Heritage Foundation and NOAA Ocean Exploration to find and document the wreckage of Pan Am Flight 526A, characterizing this important cultural heritage resource while bringing closure to the families of the victims and ensuring future protection of the site. 

The project began in August 2019 when NOAA issued a call for input from its partners to identify areas of interest in the mid-Atlantic, US east coast and Caribbean. Air/Sea Heritage president Russ Matthews, still fresh from the first “Search for Samoan Clipper”expedition a month earlier, and full of information about Pan American Airways history, recalled the story of Clipper Endeavor’s loss near Puerto Rico and initiated a new research effort. 

Careful review of the Civil Aeronautics Board Accident Investigation Report revealed that the Pan Am crew were in radio contact with the airport tower throughout the incident and that the pilots on another plane witnessed the ditching and remained aloft to help direct rescuers from the US Coast Guard and Air Force to the scene. Given these circumstances, combined with the number and professionalism of the participants involved, confidence in the estimated sinking position was rated extremely high.

ASHF Samoan Clipper project co-lead, maritime archeologist Dr. Michael Brenan (SEARCH, Inc) reached out to sonar expert Gary Fabian to determine if there were any newer clues pointing to the location of the lost Pan Am airliner. Fabian combed through existing multibeam data for the region and learned that NOAA ship Okeanos Explorer had previously surveyed the suspect area in the past few years. His analysis showed a relatively flat seafloor composed of softer sediment, ranging in depth between 500 and 600 meters. And within one nautical mile or less from the US Coast Guard’s estimated crash position for Clipper Endeavor he plotted four intriguing anomalies, all of which appear in both the backscatter and bathymetric readings. It is worth noting here that, working from similar information in 2016, Fabian pointed researchers on board Okeanos Explorer to the discovery of wreckage from a WWII Boeing B-29 heavy bomber (with  nearly the same dimensions as a DC-4 airliner) in 374 meters of water off the coast of Tinian Island, Commonwealth of the Northern Marianas.

A targeted search for the remains of Clipper Endeavor seemed feasible, but it would take an extremely capable research vessel with a robust ROV (Remote Operated Vehicle) system to tackle it. NOAA’s Ocean Exploration team agreed with this assessment and tasked Okeanos Explorer to investigate .. in April of 2020. However, the worldwide COVID-19 pandemic and ensuing lockdowns meant the cancellation of the planned Clipper Endeavor dive along with much of that field season. Another two and a half years, plus a few “near misses,” would pass before opportunity suddenly knocked again.

On 19 August 2022, operational necessity forced NOAA Ship Okeanos Explorer to divert to San Juan, and refocus its efforts in the Puerto Rico area. While unfortunately upsetting to the carefully planned “Voyage to the Ridge expedition” then underway, NOAA and ASHF immediately recognized the extraordinary chance to renew their search for Clipper Endeavor and plans were quickly set in motion. Before making port on the morning of 23 August 2022, Okeanos Explorer made several mapping runs with its hull-mounted multibeam sonar in the vicinity of the proposed search area, to acquire the most up to date data. After the announced resupply call at San Juan, the ship will return to sea and prepare for a dive on the Clipper Endeavor target(s), scheduled to commence at 9:00 a.m.EDT on Thursday, 25 August. The crew will perform what is known colloquially as a “stop and drop” dive with the tandem Seirios/Deep Discoverer ROV system on the first two anomalies and determine if they are natural features or aircraft wreckage. The vehicle may possibly be placed in tow configuration for a fast transit to inspect the third and perhaps fourth targets. In the event of an archaeological discovery, the ROV team will work to characterize and document the remains of the sunken plane. Clipper Endeavor is known to have gone down virtually intact (save for a portion of the tail that separated aft of the rear bulkhead). Its main fuselage and wings (spanning 117.5 feet) with four massive Pratt & Whitney R-2000 Twin Wasp radial engines on the leading edge make for a highly distinctive target. Numerous markings present on Pan American airliners in general (and Clipper Endeavor in particular) could be used to aid in a swift and conclusive visual identification. No attempt will be made to recover artifacts from the wreck.