The Secret Agent on Flight 101 Read online

  “A trick he could have learned from Hexton,” Frank mused.

  “And another thing,” Chet went on, “the green sedan was Hexton’s and it has not been picked up.”

  “What about the second call?”

  “It was from Kenneth Dell,” Chet answered. “He wants to talk to you as soon as possible.”

  Frank picked up the phone and dialed the private number of the Great Circle Airways’ security chief.

  Dell sounded excited. “I’ve had a report that one of our flight stewards, named Timken, has been acting suspicious lately. He used to be friendly and stay around for a while after landing. Now shortly after he gets in from Scotland on Flight 101, he leaves in a waiting helioplane. He never says where he’s going.”

  “That is strange,” Frank remarked. “A helioplane! The kind that can take off and land in short distances?”

  “Right! It can also fly at very low speeds.”

  “Have you any idea where the steward goes?” Frank asked.

  “No flight plan was filed,” Dell said.

  “Who owns the plane?” Joe inquired.

  “I don’t know, but now I mean to find out,” Dell replied. “Whenever the pilot has asked for landing instructions, he has identified himself as ‘Helioplane 345.’ Of course those are only the last three figures in his whole number.”

  Joe asked, “What about Timken as a steward?”

  “He was hired by our firm only a couple of months ago. Seems efficient and so far we haven’t found anything incriminating in his record. Flight 101 is part of his regular schedule, and I’m watching it for anything the least bit suspicious. With Hexton’s headquarters probably in a Scottish castle, we can’t be too careful about our Scotland flights.”

  “I have an idea,” said Frank. “The next time Timken takes the helioplane, Joe and I will follow him.”

  “Follow him?” Dell said. “How?”

  “In Dad’s plane.”

  “But if you were to take off immediately behind the helioplane and trail it on the same course,” Dell countered, “wouldn’t that arouse the pilot’s suspicions?”

  “We would take off from a different airport,” Frank said. “Hold on just a minute, will you?”

  He beckoned Joe, who handed him an aeronautical chart. Spreading it out, Frank examined the area in the vicinity of Great Circle’s base. Then he picked up the phone again.

  “There’s a small general airfield at Burnsbie near your base,” he told Dell. “We’ll land there and wait. When you see the steward boarding the helioplane, let us know.”

  “It might just work at that,” the SKOOL agent agreed.

  “What is Timken’s first name and when is he scheduled to return from his next flight?” Frank asked.

  “Stand by. I’ll check the crew schedule.” There was a brief pause, then Dell came on again. “His first name is Guy, and he’s scheduled for an outgoing flight tonight. He’ll be back here at ten o’clock Thursday morning, our time.”

  “Good!” Frank said. “Barring bad weather, we’ll plan to be at the field at least an hour before Timken is due back.”

  Frank said good-by, then called Jack Wayne and informed him of the plan. The pilot said he would have the plane fueled and ready to fly Thursday morning at the crack of dawn.

  As the first rays of sunlight appeared in the east that day, the Hardys got up and dressed. They were surprised to find their mother and Aunt Gertrude already in the kitchen preparing breakfast for them.

  “Um! Sausage and cakes!” Joe said with a grin.

  Immediately after breakfast, the boys drove to Bayport Airport. There they made a final check on the weather. The forecaster told them it would be CAVU-Geiling and Visibility Unlimited—for at least another forty-eight hours.

  “The ship’s all set to fly!” Jack Wayne called as they walked across the ramp.

  He and the Hardys got into the plane and fastened their seat belts. A sudden roar echoed across the field as Jack started engines. He made a quick but thorough check of the instruments. Minutes later, they were airborne and climbing rapidly above Bayport.

  “We should get to Burnsbie with plenty of time to spare,” Frank said as he glanced at his watch.

  Upon arriving at their destination, Jack at tended to the refueling of the plane, while Frank and Joe waited in the operations room for a call from Kenneth Dell.

  It was a few minutes after ten o’clock when the telephone rang. The airport manager scooped up the receiver, then announced that the call was for the boys.

  “This is Kenneth Dell, Frank! Timken just got into the helioplane. They’re taxiing out now for take-off.”

  “Roger!” declared the young detective. “We’re on our way.”

  In a matter of minutes, Jack Wayne and the Hardys were approaching Great Circle’s base at several thousand feet.

  “There’s the helioplane!” Joe exclaimed. “It’s at the three-o’clock position.”

  The craft veered slightly to a northeast course. Jack followed at a safe distance.

  A short time later the helioplane made two complete turns, then reverted to course. Jack did the same. Moments later, their quarry repeated the maneuver.

  “Why all those turns?” Joe asked.

  “He’s probably checking to see if he’s being followed,” Jack replied.

  “Do you suppose he spotted us?” Joe asked.

  Frank replied, “No doubt. But we’ve nothing to lose by continuing the chase.”

  The gap between the two crafts, however, decreased more and more as the helioplane reduced speed.

  “That clunker up ahead can fly much slower than we can.” Jack’s voice showed concern.

  He attempted to keep his distance, but another glance at the airspeed indicator told him that their plane was dangerously near to a stall. The Hardys tightened their seat belts when the craft began to buffet.

  “Sorry, boys,” the pilot said. “I can’t make it.” He was about to increase power when suddenly the helioplane executed a sharp turn and headed directly for them. Jack quickly maneuvered out of the way, but the sharp movement of the controls caused the aircraft to stall.

  The plane rolled into an almost inverted position and dived vertically toward the ground!

  CHAPTER VII

  Suspect on the Run

  FRANK and Joe were thrown against their seat belts as the plane dropped earthward, and the wind whistled an eerie dirge against the wings.

  “Hang on!” Jack shouted as he pulled the throttle closed and applied aileron and rudder control.

  He managed to level the wings, then concentrated on recovering from the steep dive. As he eased back slowly on the wheel, the boys were pressed down into their seats by the increasing G force.

  Finally Jack had the aircraft back to straight and level—but with not much altitude to spare. He increased power and the plane climbed higher. For a moment nobody spoke.

  “Whew!” Joe finally exclaimed as he wiped perspiration from his face. “I can’t say I’m too keen on this kind of maneuver.”

  “Whoever is flying that helioplane,” Jack Wayne remarked, “is a pretty good pilot.”

  “Keep a sharp lookout,” Frank urged as he searched the sky above them.

  They continued to gain altitude and the boys scanned the area on all sides. Ahead, puffy white cumulus clouds built up over the hilly terrain.

  “I’m afraid we’ve lost our quarry,” the pilot said. “And I’ll bet they’re members of UGLI!”

  “Yes, worse luck,” Frank answered. “The clouds offer excellent cover. Trying to find those agents in it would be like trying to find a flea in a fog.”

  The Hardys decided to discontinue the chase and return to Great Circle’s base. Upon landing, an announcement came over the public-address system.

  “Frank and Joe Hardy, please report to the operations room.”

  The young sleuths sprinted to the administration building. In the operations room Kenneth Dell was clutching a telephone to his e
ar.

  “What’s up?” Frank asked.

  “Flight Service has just given me the helioplane’s full registration number. I told them to let me know if they heard anything from the pilot,” Dell said. “Looks as if we’re in luck! He ran into bad weather north of here, and had to file an instrument flight plan.”

  “What’s his destination?” Joe asked.

  “Logan International Airport, Boston,” the security chief replied.

  “Jeepers!” Joe exclaimed. “Do you think that’s where he was headed all the time?”

  “I doubt it,” Frank replied. “Timken wouldn’t want anyone to know where he’s going. I think they’re just planning to land and wait for the weather to clear. Then they can continue the trip without a flight plan.”

  Dell signaled for silence as he pressed the receiver closer to his ear. He jotted down a few notes and then hung up.

  “Here’s something else,” he announced. “The pilot’s name given on the flight plan is Mazer. And the owner of the helioplane is the Coastal Courier Service.”

  “Say,” Joe spoke up, “why don’t we have Jack fly us to Boston right away? Logan is a busy airport. Timken might not notice our arrival.”

  “Good idea,” Dell said. “In the meantime, I’m going to check out this information.”

  An hour and a half later Jack Wayne and the boys were cleared for an ILS approach at Logan International Airport.

  “Looks as if the weather’s beginning to improve,” Jack remarked as they taxied to the parking ramp.

  “I don’t see the helioplane anywhere,” Joe observed.

  “We’ll check with operations,” Frank said.

  The boys hurried into the administration building. They located the operations manager and inquired about the helioplane.

  “Why, yes,” he said. “I remember the craft distinctly. It caught my eye, since that kind of thing is a rarity around here.”

  “Where is it now?” Joe asked.

  “I think it took off about thirty minutes ago,” the operations manager replied. “But why don’t you check with the control tower?” He pointed to a wall telephone. “That’s a direct line.”

  Frank picked up the phone.

  “Logan Tower! Stigand speaking!” crackled from the receiver.

  Frank said, “A helioplane departed from here about half an hour ago. Can you tell me its destination?”

  “Stand by!”

  There were a few seconds of silence, then Stigand reported, “The pilot filed an instrument flight plan for Concord Airport, New Hampshire. However, he broke into clear weather at Manchester and canceled his flight plan.”

  “Thank you,” Frank replied, dejected.

  “So we’ve lost them again,” Joe remarked.

  “Timken and his pilot played it smart,” Frank said. “They knew they’d fly into clear weather. I’ll bet they never had any intention of landing at Concord.”

  Just then two men approached the youths.

  “What’s your interest in the helioplane?” one of them demanded.

  “Who are you?” Joe retorted.

  “We’re detectives! Boston Police Department!” They flashed their badges.

  “My name is Amory,” one said. He pointed to his partner. “And this is Detective Sergeant Doran.”

  Frank introduced himself and his companions.

  “Hardy!” Amory exclaimed. “Any relation to Fenton Hardy the private detective?”

  “We’re his sons,” Joe answered.

  “Why did you ask us about our interest in the helioplane?” Frank inquired.

  “A couple of hours ago a local jeweler was approached by a fellow who tried to sell him a diamond. When the jeweler began to question him as to where he got it, the guy walked out. The jeweler became suspicious and called us.”

  “What started you looking for this man at the airport?” Joe asked.

  Amory replied, “The jeweler said he was wearing a Great Circle Airways uniform. So the airport seemed a logical place to begin a search, although Great Circle doesn’t come in here. We want to ask that fellow a few questions.”

  “He’s gone,” Frank said. “The man you’re looking for is the same one we’ve been following. He took off in the helioplane about half an hour ago.”

  “That adds up,” Doran commented. “The operations manager told us a fellow answering the jeweler’s description had already left.”

  “We approached you boys,” Ames added, “because we heard you inquiring on the phone about the helioplane.”

  There was little more the young sleuths could do, so they took off. During the return flight to Bayport, they mulled over the latest event.

  “What do you make of Timken trying to peddle a diamond?” Joe asked.

  “It sounds to me like an attempt to get rid of stolen goods,” Frank concluded.

  “Could be,” Joe said thoughtfully. “You remember Dad’s report said that Hexton’s gang were robbers. If Timken is one of them, he may be smuggling in jewels stolen overseas and disposing of them here.”

  Frank agreed. “But UGLI’s business is espionage. I doubt if they would become involved in jewel robberies. On the other hand, Hexton and his gang might be playing the two games at once.”

  When the boys arrived home, Frank at once telephoned their suspicions to Kenneth Dell.

  “You have a good theory there,” Great Circle’s security chief said. “I’m going to call Scotland Yard and inquire about recent jewel robberies.” He promised to get in touch later.

  After Frank hung up the phone, he stood silent for a moment. “Next we must figure out that message Dad left on the hotel wall,” he told Joe.

  Again they examined the row of numerals: 441810682300. But after more than an hour of attempting to decipher them, Joe gave a sigh of frustration. “It doesn’t make any more sense to me now than when we first started,” he admitted.

  “If this is a code, it’s a real puzzler,” Frank agreed. “But we’ve got to crack it!”

  When Mrs. Hardy announced that dinner was ready, the boys reluctantly interrupted their task. They ate quickly, then went right back to the message.

  Frank stared at it. “Neither the substitution nor transposition ciphers jibe.”

  The young detectives worked late into the night. Exhausted, they finally went to bed.

  Early the next day Frank and Joe continued to study the message, but all their efforts to decipher it ended in failure.

  Shortly after ten o’clock Chet arrived at the Hardys’ home. He plodded up the stairs to the detective’s study.

  “You’re too late for breakfast, chum,” Frank said with a grin.

  “Aw, cut it out,” Chet mumbled. “Anyway, I stopped at Biff Hooper’s house before I came here. His mother was baking the most delicious pancakes I ever saw, with sausages and all the trimmings.”

  “Glad to hear that,” Joe said jokingly. “We wouldn’t want to see you fade away.”

  “How is Biff?” Frank inquired as he glanced at his friend. Biff Hooper was a schoolmate of the boys at Bayport High.

  “He’s just fine. I wanted to show him a couple of my magic tricks.”

  “Don’t tell us you took that silver bowl of yours along?” Joe asked.

  “No, that’s old stuff,” Chet retorted. “My new tricks are more sophisticated.”

  “Oh yeah!” said Joe, chuckling.

  “Go ahead and laugh if you want to,” Chet continued indignantly. “At least Biff appreciated the great latitude of my genius.”

  At Chet’s remark, Frank sat bolt upright in his chair.

  “What’s the matter?” Chet asked, startled.

  “Would you repeat what you just said?” Frank asked excitedly.

  “You mean about Biff’s appreciating the latitude of my genius?”

  Frank sprang up. “The key! You’ve given me the key!”

  CHAPTER VIII

  Sailing Sleuths

  CHET looked confused. “What key? I don’t see any key,” h
e said, glancing around.

  “You mentioned latitude! That must be it—latitude and longitude!” Frank pointed to the numerals in the mystery message.

  “I still don’t get it,” said Chet.

  Frank explained. “Notice that there are a total of twelve digits. The first six—441810—must mean 44 degrees, 18 minutes, 10 seconds of latitude. The remaining figures—682300—would then stand for 68 degrees, 23 minutes, 00 seconds of longitude ”

  “You’re right!” Joe exclaimed.

  Frank riffled through a stack of maps and selected one showing the Atlantic seaboard. “Those coordinates would locate a position in the area covered by this map.”

  “Hold on!” Joe said as he glanced at a chart of the world that he had just unfolded. “The message doesn’t specify whether the latitude is east or west, or the longitude north or south. Therefore, these coordinates might designate a location in Asia, the southern tip of South America, or the middle of the Indian Ocean.”

  “True,” Frank agreed. “But since Dad didn’t make that clear in the message, I’m certain he means the position is in our own hemisphere.”

  He marked the spot on his map indicated by the coordinates. It was about eighteen miles off the northeast coast of the United States.

  “But that’s a spot in the Atlantic Ocean!” Joe exclaimed.

  Frank pulled out a nautical chart. It was on a smaller scale and showed more detail. Replotting the position, he discovered several small islets in the vicinity—so small they did not have names. The latitude and longitude coordinates lay directly over one.

  “Eureka!” Joe exclaimed. “It looks as if we’re onto something! My guess is one of two possibilities—either the place is UGLI’s headquarters for the U.S., or else it’s where Dad was taken.”

  “Maybe it’s both,” Joe added. “We’d better make a trip to that island!”

  “What about me?” Chet demanded. “Can I come, too? After all, I found the key!”

  Frank bowed toward his chum. “It’ll be a pleasure to have you along, genius,” he said. “We might need your help.” Then he walked to the telephone. “I’ll call Jack and tell him to have the plane ready tomorrow morning.”