(CNN) -- Joe Kistel and Penny Malphrus have never met. But they are connected in a way that may help provide each of them with an answer to the same question: Could strewn pieces of metal recently found partially buried in the sandy ocean floor 20 miles off the coast of St. Augustine, Florida, be what's left of a plane that disappeared without a trace 16 years ago?
The story begins on February 17, 1996.
That's the day Penny's father, Stewart Dunbar, an experienced pilot, took off on a short solo flight from Swainsboro, Georgia, to Hilton Head Island, South Carolina. Dunbar was returning home after going to show his twin engine propeller-driven Piper Aerostar to a prospective buyer who, as it so happened, failed to show up for the scheduled appointment.
Shortly after he took off around 7:45 p.m., Dunbar, 58, reported feeling dizzy and said he was having trouble seeing. He radioed a distress call and advised the radio control tower in Jacksonville, Florida, of his coordinates. In what would be his last communication, he said he was placing the plane on autopilot and turning toward the ocean.
Though never certain, the family believes Dunbar, realizing his predicament and unable to control the light transport aircraft, wanted to steer the plane away from land and avoid hurting anyone.
If her father was unconscious, Penny Malphrus, who was 24 at the time, theorizes, his body might have shifted against the controls, putting the plane down off the coast near Jacksonville.
Two fighter jets were scrambled from a Navy base at Charleston, South Carolina, and got close enough to see the plane but couldn't see inside the cockpit. The fighters ran low on fuel and turned around.
Despite a lengthy aerial and water search by the Coast Guard and Navy, not a single piece of Dunbar's plane was ever found.
"I spend countless weeks imagining his fuselage possibly still intact, bouncing around in the ocean like a bottle thrown to sea waiting to be found," Malphrus, now 39, said quietly this week from the same Hilton Head Island home where she grew up.
"If there's a chance he could still be alive somehow, he will find me here waiting, same address, same phone number as it was before and always will be," she said with a mixture of hope and resignation.
"If he survived, I was certain he was out there floating around like a cork surviving on the snack pretzels, chips and soft drinks that he always kept onboard for his passengers," she reflected.
Enter into the narrative: 31-year-old Joe Kistel, the executive director of TISIRI (Think It Sink It Reef It), a non-profit Jacksonville-based marine conservation company in the business of protecting the habitat and building artificial reefs.
About three weeks ago, Kistel was preparing to visit reef sites off the Florida coast to take pictures for TISIRI's interactive reef map project used by researchers, tourists and maritime enthusiasts.
Kistel said his depth finder detected something on the sea floor and what looked like fish 80 feet below the surface.
"We decided to check it out, out of curiosity," he said. "You just never know."
He and another diver put on scuba gear and went down but didn't find any fish. They expanded their search. That's when they noticed a weed-shaped object like a coat hanger, a piece of stainless steel and other debris that Kistel initially thought might have fallen off a barge.
What they found were plane parts: two Lycoming piston engines, an engine block and a bent propeller, but no fuselage. Lycoming engines were used on Piper Aerostars. They took photos and, once on shore, started looking for answers.
Hearing about the discovery, local fishermen led them to a second site about four miles away where there is a second plane, a larger, perhaps military-type aircraft with at least three tires.
Kistel went online to post dozens of photos and video of both sites and to ask the public for help in identifying the planes. Were they remnants of World War II era planes or more recent aircraft?
Kistel and his team planned to dive this weekend to bring up what they could, but bad weather forced them to reschedule. His company, with its limited budget, isn't equipped to raise heavy pieces, but he said they may be able to use a float bag to drag some of the parts to shore. If they don't work quickly, they worry a hurricane will come along and bury the site.
Malphrus will be anxiously waiting. "Anything for closure," she said. She acknowledges she never stops looking, wondering.
"I still check the horizon of the coastline here in Hilton Head Island every day and the newspapers every night," she said.
Just this week, she and her 9-year-old son, Trent, were walking on the beach right after high tide in the moonlight to observe hundreds of turtles hatching. "We watched every single one with their cute little wiggly waddle all the way to the water where they just took off. No fear at all," she said.
Around midnight, Malphrus and her son came upon something unusual partly covered in sand. Could this be it, she thought, part of her father's plane? They started digging and eventually uncovered what appeared to be a gigantic rudder from a ship.
"Never a day goes by that I don't think of him," she said by phone the next day. "My Dad was the most amazing man."
Her search continues. She hopes Joe Kistel finds the answer this time.