27 October 2015: The first flight of the Sikorsky CH-53K King Stallion Engineering Development Model–1, Bu. No. 169019, at West Palm Beach, Florida. In the cockpit was Stephen McCulley, Chief Experimental Test Pilot for Sikorsky. During the 30 minute flight, the new helicopter demonstrated sideward, rearward and forward flight while remaining in in-ground-effect hover.
Up to this point, the helicopter had completed about 200 hours of “turn-time,” or ground testing, with engines running..
Three more aircraft will join the test fleet for a planned 2,000 hour flight test program.
The fuselage of the CH-53K King Stallion is 73 feet, 1.5 inches (22.289 meters) long and its width is 9 feet, 10 inches (2.997 meters). The maximum width, across the sponsons, is 17 feet, 6 inches (5.334 meters). The seven-bladed main rotor has a diameter of 79 feet (24.079 meters). The four-blade tail rotor is 20 feet (6.096 meters) in diameter. The tail rotor is tilted 20° to the left. With rotors turning, the helicopter has an overall length of 99 feet (30.175 meters), and height of 28 feet, 4.9 inches (8.659 meters). The helicopter’s maximum gross weight is 88,000 pounds (39,916 kilograms).
Power is supplied by three General Electric T408-GE-400 engines which produce 7,500 shaft horsepower, each. The engine has digital electronic controls. The T408 has a 6-stage compressor section (5 axial-flow stages, 1 centrifugal-flow stage) and – stage turbine section (2 high- and 3 low-pressure stages). The engine is 57.5 inches (1.461 meters) long and 27 inches (0.686 meters) in diameters.
At Sea Level with maximum continuous power, the CH-53K cruises at 158 knots (182 miles per hour/293 kilometers per hour). It can hover out of ground effect at Sea Level at its maximum gross weight. The helicopter’s service ceiling is 16,000 feet (4,877 meters).
The first production CH-53K was delivered to the U.S. Marine Corps on 16 May 2018, at West Palm Beach, Florida.
27 October 1961: At 15:06:04 UTC, (10:06 a.m., EST), 3.97 seconds after ignition, the first Saturn C-1 heavy launch vehicle (Saturn I, SA-1) lifted off from Launch Complex 34 at Cape Canaveral, Florida. This was a test of the first stage, only. The rocket’s upper stages were dummies.
At about 109 seconds after liftoff, four inner engines of the first stage shut down, followed 6 seconds later by the outer four. The rocket continued on a ballistic trajectory.
The Saturn C-1 was bigger than any rocket built up to that time. Early versions of the three-stage rocket were 162 feet, 8.90 inches (49.6037meters) tall, with a maximum diameter of 21 feet, 5.0 inches (6.528 meters). The all-up weight was 1,124,000 pounds (509,838 kilograms).
The first stage of SA-1 was built by the Marshall Space Flight Center (MSFC) at Huntsville, Alabama. The S-I stage was built up with a Jupiter rocket fuel tank in the center for liquid oxygen, surrounded by eight Redstone rocket tanks. Four were filled with RP-1 propellant, alternating with four filled with LOx. The first stage was powered by eight Rocketdyne Division H-1 engines rated at 165,000 pounds of thrust (733.96 kilonewtons), each. Total thrust for the first stage was 1,320,000 pounds (5,871.65 kilonewtons). The outer four engines were gimbaled to steer the rocket. (The S-I Block I stage had no fins.)
The first stage had been test fired 20 times before being transported to Cape Canaveral by barge.
For the first flight, SA-1, the S-!V second stage and S-V third stage were dummies. The S-IV was filled with 90,000 pounds (40,823 kilograms) of water for ballast. The S-V third stage, carried 100,000 pounds (45,359 kilograms) of water. Mounted above the third stage was a Jupiter nose cone.
The Saturn C-1 weighed 925,000 pounds (419,573 kilograms). It contained 41,000 gallons (155,200 liters) of RP-1, a refined kerosene fuel, with 66,000 gallons (249,837 liters) of liquid oxygen oxidizer— 600,000 pounds (272,155 kilograms) of propellants.
SA-1 reached a maximum speed of 3,607 miles per hour (5,805 kilometers per hour), and a peak altitude of 84.813 miles (136.493 kilometers). It impacted in the Atlantic Ocean 214.727 miles (345.570 kilometers) down range. The duration of the flight was 15 minutes, 0 seconds. The flight was considered to be nearly flawless.
October 27, 1954: between August 1954 and May 1956, Joseph A. Walker, the National Advisory Committee for Aeronautics’ chief project test pilot for the Douglas X-3 supersonic research aircraft, made twenty research flights in the “Stiletto.”
On the tenth flight, 27 October, Walker took the X-3 to an altitude of 30,000 feet (9,144 meters). With the rudder centered, he put the X-3 into abrupt left aileron rolls, first at 0.92 Mach and then at Mach 1.05. Both times, the aircraft violently yawed to the right and then pitched down. Walker was able to recover before the X-3 was completely out of control.
This was a new and little understood condition called inertial roll coupling. It was a result of the aircraft’s mass being concentrated within its fuselage, the gyroscopic effect of the turbojet engines and the inability of the wings and control surfaces to stabilize the airplane and overcome its rolling tendency. (Just two weeks earlier, North American Aviation’s Chief Test Pilot George S. Welch had been killed when the F-100A Super Sabre that he was testing also encountered inertial roll coupling and disintegrated.)
A post-flight inspection found that the X-3 had reached its maximum design load. The airplane was grounded for the next 11 months.
The Douglas X-3, serial number 49-2892, was built for the Air Force and NACA to explore flight in the Mach 1 to Mach 2 range. It was radically shaped, with a needle-sharp nose, very long thin fuselage and small straight wings. Two X-3 aircraft had been ordered from Douglas, but only one completed.
The X-3 was 66 feet, 9 inches (20.345 meters) long, with a wing span of just 22 feet, 8.25 inches (6.915 meters). The overall height was 12 feet, 6.3 inches (3.818 meters). The X-3 had an empty weight of 16,120 pounds (7,312 kilograms) and maximum takeoff weight of 23,840 pounds (10,814 kilograms).
It was to have been powered by two Westinghouse J46 engines, but when those were unsatisfactory, two Westinghouse XJ34-WE-17 engines were substituted. This was an axial flow turbojet with an 11-stage compressor and 2-stage turbine. It was rated at 3,370 pounds (14.99 kilonewtons) of thrust, and 4,900 pounds (21.80 kilonewtons) with afterburner. The XJ34-WE-17 was 14 feet, 9.0 inches (4.496 meters) long, 2 feet, 1.0 inch (0.635 meters) in diameter and weighed 1,698 pounds (770 kilograms).
The X-3 had a maximum speed of 706 miles per hour (1,136 kilometers per hour) and a service ceiling of 38,000 feet (11,582 meters).
The X-3 was very underpowered with the J37 engines, and could just reach Mach 1 in a shallow dive. The X-3′s highest speed, Mach 1.208, required a 30° dive. It was therefore never able to be used in flight testing the supersonic speed range for which it was designed. Because of its design characteristics, though, it was very useful in exploring stability and control in the transonic range.
At one point, replacing the X-3’s turbojet engines with two Reaction Motors XLR-11 rocket engines was considered. Predictions were that a rocket-powered X-3 could reach Mach 4.2. However, with Mach 2 Lockheed F-104 becoming operational and North American Aviation’s X-15 hypersonic research rocketplane under construction, the idea was dropped. Technology had passed the X-3 by.
In addition to Douglas Aircraft test pilot Bill Bridgeman, the Douglas X-3 was flown by Air Force test pilots Lieutenant Colonel Frank Everest and Major Chuck Yeager and NACA pilot Joe Walker.
Joe Walker resumed flight testing the X-3 in 1955. Its final flight was 23 May 1956. After the flight test program came to an end, the X-3 was turned over to the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio.
25 October 1931: At 5:17:30 p.m., Pacific Standard Time, Saturday afternoon (01:17:30, Sunday, 26 October, G.M.T.), Ruth Rowland Nichols took off from Oakland Municipal Airport, in California, and headed east. He destination was New York City, New York, non-stop.
Miss Nichols was flying a 1928 Lockheed Model 5 Vega Special, serial number 619, registered NR496M, and owned by Powell Crosley, Jr. The airplane had just been repaired following a landing accident three months earlier, in which she had suffered five fractured vertabrae. [TDiA 22 June 1931] The Vega was white with gold wings. A list of records which had been previously set by Miss Nichols was lettered in gold on the forward fuselage.
At 7:35 p.m., Mountain Standard Time (02:35, Sunday, G.M.T.) the Vega was sighted over Reno, Nevada. It was over Salt Lake City, Utah, at 11:00, local time (06:00 G.M.T.), and Cheyenne, Wyoming, at 1:07 a.m., Sunday, Central Standard Time (07:07 G.M.T.).
Ruth Nichols and her Lockheed landed at Bowling Field, Louisville, Kentucky, at 9:40 a.m., Sunday, local time (15:40 G.M.T.). Though well short of her intended destination, she had set a new Fédération Aéronautique Internationale (FAI) World Record for Distance in a Straight Line Without Landing of 3 182,65 kilometers (1,977.607 statute miles). This broke the record set 29 June 1931 by Mlle Maryse Bastie during a flight from Paris, France, to Udino, Russia.²
Ruth Nichols described her flight for a newspaper syndicate:
Miss Nichols Tells the Story of Her Flight
Says High Altitudes During Trip Caused Dizziness.
The following account of her non-stop flight from Oakland, Calif., to Louisville was written by Miss Ruth Nichols for the Courier-Journal and the North American Newspaper Alliance.
By RUTH NICHOLS.
(Copyright, 1931, By North American Newspaper Alliance, Inc.)
Twelve hours of darkness is a long time, particularly when the sky is overcast. Although the moon was out, the horizon line was hazy, and over the Western plains, where there are only a few towns, the only contact with civilization that a flier has is a twinkling beacon that is often lost behind a gigantic mountain peak.
Because of the difficulty in seeing the mountain passes easily, an average high altitude is wise, but I found that after eight hours of flying around 15,000 feet made me dizzy.
Used Oxygen Supply.
I had an oxygen tank with me, and I have spent a considerable amount of times at high altitudes, but the indistinctness of the night has a tendency to diffuse one’s senses, and the oxygen resulted in too much of a boost.
At times I felt myself soaring out of the ship, and, twice while the sky was overcast and the ship still heavily loaded, I had a nightmare of a time to keep from slipping off into a power spin.
At times like that, it is necessary to keep busy doing something. It keeps the circulation going.
The cube-like boundary lights of emergency fields are a welcome sight in those barren places. Many of the mountains are now snow-capped, and the lakes and rivers glisten white when the moon is out, making navigation simple.
About every hour I saw a cobweb of lights, which meant a large town, and marked off a milestone in the long night. There was a strong drift at times, but I always had a favorable wind.
The hour before dawn is certainly the darkest. Then the horizon seems often to disappear entirely. My, how welcome that streak of red dawn is!
To avoid low ceilings over the Alleghanies, I headed south, and thus ran low in gas, and landed here.
People often ask me what a flier thinks about. Much and many things! I wondered what the fields are like if a forced landing is necessary, how long will the batteries last, my goodness! There I dropped the coffee thermos.
Every time I took my foot off the rudder to pick it up by means of my toe and hand, teh ship slid off into a near spin.
I wondered how much gas that good old motor was using. I thought: Why, there is Orion!—and then wondered where the Little Bear constellation was hiding. And finally, I observed: That looks like nice country for a horseback trip!
Then there is the question: “What is the value of establishing all these records?”
The answer is that for a girl to fly long distances shows the facility and safety of handling a present-day airplane.
That ride over our country at night is really a most inspiring event. I advise everyone to try it!
—The Courier-Journal, Vol. CLIV. New Series—No, 22,944, Monday 26 October 1931, Page 1, Column 6, and Page 2, Column 7
Nichols had planned to resume her flight to New York at 9:00 a.m., Monday morning, 27 October. That was not to be, however:
WOMAN FLYER’S SHIP DESTROYED
Ruth Nichols Jumps From Blazing Plane
Defective Valve Deluges Craft With Gasoline
Aviatrix Unhurt in Leap From Cabin Window
LOUISVILLE (Ky.) Oct. 26. (AP)—Ruth Nichols’s monoplane caught fire today as she was warming up to take off for New York. She leaped from a window of the cockpit barely in time to escape the flames.
The young aviatrix stumbled as she reached the ground, but mechanics grabbed her and hustled her away from the fiery plane. The plane was reported almost a total loss.
The was caused by a stream of gasoline that suddenly burst from beneath the plane. Attendants at Bowman Field said they believed a dump valve had been released by the vibration of the engine.
The dump valve, Miss Nichols said, gave her some trouble in California, but she had a new one installed there. She talked while city firemen arrived and after a half hour’s work extinguished the flames.
The Rye (N.Y.) aviatrix, who landed here yesterday from Oakland, Cal., after getting lost in the early morning, but still making what is believed to be a new distance record for women, first noticed something wrong from the frantic signals of mechanics. It was doubtful if she heard their cries above the roar of the motor.
Miss Nichols throttled down her engine before getting out, but had only a moment in which to escape. The accident occurred just as she gave the motor “the gun” for warming up after she had inspected the refueling and checked up on the monoplane and had studied weather reports for the New York flight.
AVIATRIX SUFFERING FROM LAST CRASH
NEW YORK, Oct 26. (AP)—Friends of Ruth Nichols, pleased that she was unhurt when she leaped from the high cockpit of her burning plane at Louisville, recalled today she is still wearing a steel corset to protect the vertebra she smashed in the first stage of a proposed Atlantic flight last summer.
Miss Nichols crashed in landing at St. John, N.B., on the first leg of her projected ocean flight, which was abandoned. Her plane was demolished and she was injured seriously. For a long time she wore a plaster cast to protect her spine and this was recently replaced by the steel corset.
—Los Angeles Times, Vol. L., Tuesday, 27 October 1931, Part I, Page 3, Column 6
Nichols’ airplane was a 1928 Lockheed Model 5 Vega Special, serial number 619, registered NR496M, and owned by Powell Crosley, Jr., founder of the Crosley Radio Corporation, a manufacturer of radio equipment and owner of a broadcast network based in Cincinnati, Ohio. He had named the airplane The New Cincinnati. Miss Nichols called it Akita.
Built by the Lockheed Aircraft Company, Burbank, California, the Vega was a single-engine high-wing monoplane with fixed landing gear. It was flown by a single pilot in an open cockpit and could be configured to carry four to six passengers.
The Lockheed Vega was a very state-of-the-art aircraft for its time. The prototype flew for the first time 4 July 1927 at Mines Field, Los Angeles, California. It used a streamlined monocoque fuselage made of molded plywood. The wing and tail surfaces were fully cantilevered, requiring no bracing wires or struts to support them.
The Model 5 Vega is 27 feet, 6 inches (8.382 meters) long with a wingspan of 41 feet (12.497 meters) and overall height of 8 feet, 2 inches (2.489 meters). Its empty weight is 2,595 pounds (1,177 kilograms) and gross weight is 4,500 pounds (2,041 kilograms).
Nichols’ airplane was powered by an air-cooled, supercharged 1,343.804-cubic-inch-displacement (22.021 liter) Pratt & Whitney Wasp C nine-cylinder radial engine with a compression ratio of 5.25:1. It was rated at 420 horsepower at 2,000 r.p.m. at Sea Level, burning 58-octane gasoline. The engine drove a two-bladed controllable-pitch Hamilton Standard propeller through direct drive. The Wasp C was 3 feet, 6.63 inches (1.083 meters) long, 4 feet, 3.44 inches (1.3-7 meters) in diameter and weighed 745 pounds (338 kilograms).
The standard Vega 5 had a cruising speed of 165 miles per hour (266 kilometers per hour) and maximum speed of 185 miles per hour (298 kilometers per hour). The service ceiling was 15,000 feet (4,572 meters). Range with standard fuel tanks was 725 miles (1,167 kilometers).
¹ FAI Record File Number 12340
² FAI Record File Numbers 12345, 12346 and 14886: 2 976,31 kilometers (1,849.39 statute miles)
Pilot, 139th Aero Squadron, American Expeditionary Forces
The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting the Distinguished Service Cross to First Lieutenant (Air Service) Russell L. Maughan, United States Army Air Service, for extraordinary heroism in action while serving with 138th Aero Squadron, U.S. Army Air Service, A.E.F., near Sommerance, France, 27 October 1918. Accompanied by two other planes, Lieutenant Maughan was patrolling our lines, when he saw slightly below him an enemy plane (Fokker type). When he started an attack upon it he was attacked from behind by four more of the enemy. By several well-directed shots he sent one of his opponents to the earth, and, although the forces of the enemy were again increased by seven planes, he so skillfully maneuvered that he was able to escape toward his lines. While returning he attacked and brought down an enemy plane which was diving on our trenches.
General Orders: War Department, General Orders No. 46 (1919), Amended Supplement 1
Action Date: October 27, 1918
Maughan is credited with four enemy aircraft destroyed while flying a SPAD S.XIII C.I fighter.
Russell Lowell Maughan was born at Logan, Utah, 28 March 1893. He was the sixth of eight children of Peter Weston Maughan, an accountant, and Mary Lucinda Naef Maughan. He attended Utah Agricultural College in Logan and graduated with a bachelor of science degree in 1917.
Maughan was commissioned as a second lieutenant in the U.S. Army Signal Officers Reserve Corps, 28 May 1917. He was promoted to first lieutenant, 8 January 1918. This commission was vacated 10 September 1920 and he was appointed a first lieutenant, Air Service, United States Army, retroactive to 1 July 1920.
On 14 August 1919, Maughan married Miss Ila May Fisher at Logan, Utah. They would have three children, but divorced sometime after 1940. His son, Russell L. Maughan, Jr., would become an cadet at the United States Military Academy (West Point) and be commissioned as an officer in the U.S. Air Force.
Following the War, Lieutenant Maughan became a test pilot at McCook Field, Ohio. In 1921, he was reassigned to the 91st Observation Squadron, based at the Presidio of San Francisco.
On 14 October 1922, Rusell Maughan won the Pulitzer Trophy Race at Selfridge Field, near Mount Clemens, Michigan, before a crowd of 200,000 spectators. He set two World Speed Record during the race with his Curtiss R-6: 330.41 kilometers per hour (205.31 miles per hour) over a distance of 100 kilometers,¹ and 331.46 kilometers per hour (205.96 miles per hour) over a distance of 200 kilometers).² On 29 March 1923, he set another World Speed Record, 380.75 kilometers per hour (236.587 miles per hour),³ again flying a Curtiss R-6.
On 23 June 1924, Lieutenant Maughan flew a Curtiss PW-8 Hawk from Mitchel Field, Long Island, New York, to the Presidio of San Francisco on the west coast of California, in an elapsed time of 21 hours, 47 minutes including refueling stops enroute. This was the “Dawn-to-Dusk Flight.” For this transcontinental flight, Maughan was awarded the Distinguished Flying Cross.
On 1 October 1930, Maughan was promoted to captain. He served in the Philippine Islands from 1930 to 1935, acting as an advisor to the government until 1932. From 1932 to 1935, he served as the post operations officer. He and his family lived in Manila. They returned to the United States aboard SS Columbus, a Norddeutscher Lloyd passenger liner, arriving at New York City from Southampton, 18 August 1935.
Captain Maughan served as an aviation advisor to the governor general of the Philippine Islands, from 1935 to 1939. On 16 June 1936, Captain Maughan was promoted to major (temporary). That rank was made permanent 12 June 1939. He was promoted to lieutenant colonel, 11 March 1940. Just prior to World War II, Lieutenant Colonel Maughan was sent on a survey tour to identify suitable locations for airfields in Greenland.
During World War II, Lieutenant Colonel Maughan commanded the 60th Troop Carrier Group, a Douglas C-47 unit, 1941–42, and then, with the rank of colonel, he commanded the 51st Troop Carrier Wing during Operation Torch, the Allied invasion of North Africa.
On 25 October 1946, Colonel Maughan married Lois Rae Roylance at Las Vegas, Nevada. She was 21 years his junior. They lived in Portland, Oregon.
Colonel Maughan later commanded Lemoore Army Airfield, California, and Portland Air Force Base, Oregon.
Maughan was discharged from the U.S. Air Force, 30 November 1947, at the U.S. Army Hospital at Valley Forge, Pennsylvania. He died at the U.S. Air Force Hospital, Lackland Air Force Base, San Antonio, Texas, 21 April 1958, at the age of 65 years. He was buried at the Logan City Cemetery, Logan, Utah.
The Société Pour L’Aviation et ses Dérivés SPAD S.XIII C.1 was a single-seat, single-engine, two-bay biplane designed by Technical Director Louis Béchéreau. The chasseur was first flown by René Pierre Marie Dorme, 4 April 1917. It was constructed of a wooden framework and covered with doped fabric. Sheet metal panels covered the engine and cockpit.
The SPAD S.XIII was 20 feet, 4 inches (6.198 meters) long with the wings having an equal span of 26 feet, 3¾ inches (8.020 meters). It had an overall height of 7 feet, 6½ inches (2.299 meters). The total wing area was 227 square feet (21.089 square meters). The wings each had a chord of 4 feet, 7-1/8 inches (1.400 meters) with 0° dihedral and 1¼° stagger. The vertical gap between the upper and lower wings was 3 feet, 10½ inches (1.181 meters). The upper wing had a 1½° angle of incidence; the lower wing had 1° angle of incidence. There were ailerons on the upper wing only. They had a span of 7 feet, 3½ inches (2.222 meters) and chord of 1 foot, 7½ inches (0.495 meters). The horizontal stabilizer span was 10 feet, 2 inches (3,099 meters. Its maximum chord was 1 foot, 8¾ inches (0.527 meters). The vertical fin height was 2 feet, 7/8-inch (0.876 meters) and it was 3 feet, 11¼ inches (1.200 meters) long at the base. The rudder was 3 feet, 10-5/8 inches (1.184 meters) high with a maximum chord of 2 feet, 2 inches (0.660 meters).
The airplane had fixed wheeled landing gear which used rubber cords (bungie cords) for shock absorption. The wheel track was 4 feet, 10¾ inches (1.492 meters). A fixed skid was used at the tail.
The the S.XIII had an empty weight of 1,464 pounds (663 kilograms) and maximum takeoff weight of 1,863 pounds (845 kilograms).
The SPAD S.XIII C.1 was powered by a water-cooled, normally-aspirated 11.762 liter (717.769-cubic-inch-displacement) left-hand tractor ⁴ Hispano-Suiza 8B single-overhead-cam 90° V-8 engine, with a 5.3:1 compression ratio. The engine drove a fixed-pitch two-bladed laminated wood propeller through a 0.75:1 gear reduction. The Hispano-Suiza 8B was rated at 235 cheval vapeur (231.8 horsepower) at 2,300 r.p.m. It was 1.36 meters (4 feet, 5.5 inches) long, 0.86 meters (2 feet, 9.9 inches) wide, and 0.90 meters (2 feet, 11.4 inches) high. It weighed 236 kilograms (520.3 pounds).
The SPAD’s main fuel tank was behind the engine, with a gravity feed supply tank in the upper wing. The total fuel total capacity was about 30 gallons (114 liters). This was sufficient for two hours endurance at full throttle at 10,000 feet (3,048 meters), including climb.
The SPAD XIII had a maximum speed at Sea Level of 131.5 mph (211.6 kilometers per hour) at 2,300 rpm; and 105 mph (169 kilometers per hour) at its service ceiling of 18,400 feet (5,608 meters), at 2,060 r.p.m. The airplane’s absolute ceiling was 20,000 feet (6,096 meters).
The fighter was armed with two fixed, water-cooled, .303-caliber Vickers machine guns, or two air-cooled .30-caliber Marlin M1917 or M1918 aircraft machine guns, with 400 rounds of ammunition per gun, synchronized to fire forward through the propeller arc.
According to a report by the National Aeronautics and Space Administration,
“. . .the SPAD XIII had the most favorable power loading of any of the aircraft considered and a high (for its day) wing loading. These characteristics coupled with a relatively low zero-lift drag coefficient and low drag area gave the SPAD the highest speed of any of the aircraft listed in the table. As shown by the data in figure 2.18, the climb characteristics of the SPAD were bettered only by three of the Fokker aircraft.”
A total of 8,742 S.XIII C.1 fighters were built by nine different manufacturers. Only one, Société Kellner Frères Constructeurs serial number 4377, the oldest existing original airplane, is in flyable condition. It is in the collection of the Memorial-Flight Association at L’aérodrome de La Ferté-Alais (LFFQ)
¹ FAI Record File Number 15195
² FAI Record File Number 15196
³ FAI Record File Number 15194
⁴ The propeller rotates clock-wise, as seen from the front of the airplane.