The Beechcraft Model 18 (or "Twin Beech", as it is also known) is a 6- to 11-seat, twin-engined, low-wing, tailwheellight aircraft designed and manufactured by the Beech Aircraft Corporation of Wichita, Kansas. Continuously produced from 1937 to November 1969 (over 32 years, a world record at the time), over 9,000 aircraft were built, making the Model 18 one of the world's most widely used light aircraft. It was sold worldwide as a civilian executive, utility, cargo aircraft, and passenger airliner on tailwheels, nosewheels, skis, or floats, and also saw use as a military aircraft.
The Model 18 was developed during the mid-to-late 1930s, primarily as a compact business aircraft and regional airliner. The prototype made its maiden flight on 15 January 1937 and gained type certification only seven weeks later. During and after World War II, over 4,500 Beech 18s were used for various military purposes, including as a light transport, light bomber (for China), aircrew trainer (for bombing, navigation, and gunnery), photo reconnaissance, and "mother ship" for target drones—including United States Army Air Forces (USAAF) C-45 Expeditor, AT-7 Navigator, and AT-11 Kansan; and United States Navy (USN) UC-45J Navigator, SNB-1 Kansan, and others. In World War II, over 90 percent of USAAF bombardiers and navigators were trained in these aircraft.
Production of the type for military purposes ended shortly after the end of World War II, the company transitioning entirely onto civil production by October 1945. During the early post-war era, the Beech 18 was the pre-eminent "business aircraft" and "feeder airliner". Besides carrying passengers, its civilian applications included aerial spraying, sterile insect release, fish stocking, dry-icecloud seeding, aerial firefighting, airmail delivery, ambulance service, numerous movie productions, skydiving, freight, weapon- and drug-smuggling, engine testbed, skywriting, banner towing, and stunt aircraft. Many Model 18s are privately owned, around the world, with 240 aircraft in the U.S. still on the Federal Aviation Administration Aircraft Registry in August 2017.
Design and development
Beech 18 on floats in Manitoba, 1986Beechcraft AT-11 over the West Texas prairies, around 1944Private Beech H18 with the optional tricycle undercarriage visiting Lannion, France
During the mid 1930s, Beechcraft management speculated that sufficient demand would exist for a new design, referred to as the Model 18. It was envisioned as a twin-engine transport aircraft, capable of seating between six and eight passengers dependent upon configuration, that would be suitable both as a business aircraft and a small regional airliner, the latter being viewed as a relatively small niche of the market due to few feeder lines existing at that time. Furthermore, the Model 18 would be designed so that it could be readily converted to be used for several military applications as well as to haul cargo. The decisions to proceed was issued in late 1935 and preliminary works commenced thereafter, which was headed by aeronautical engineer Theodore Wells. To accommodate the anticipated volume, the company's main production facilities were expanded around this time.[citation needed]
The design team investigated several different airfoils, which included a series of wind tunnel tests performed at Wichita State University, before selecting the 23000 series airfoil developed by the National Advisory Committee for Aeronautics, which possessed acceptable lift-drag profile when flying at low airspeeds and produced relatively safe stall characteristics. Furthermore, the wingroot featured an angle of incidence that progressively lessened toward the wingtips in combination with a gentle twist to the chord between the root and the wingtip that produced a smooth airflow over the ailerons (thereby retaining roll control during stalls), achieving acceptable aerodynamic performance during both landings and take-offs. The wings were furnished with electrically actuated flaps; the retraction mechanism for the undercarriage was also electrically actuated.
The resulting aircraft was fairly conventional for the era, including twin radial engines and all-metal semimonocoque construction. The flight control surfaces, such as the ailerons, elevator and rudders, were composed of aluminumalloy but covered in cottonfabric. One of the less conventional features of the aircraft was its twin-tailfin configuration. While typically outfitted with a tailwheel undercarriage, it could be interchangeably equipped with either skis or float-landing gear. The Model 18 can be mistaken for the larger Lockheed Electra series of airliners, which closely resemble it.[citation needed]
On 5 January 1937, the Model 18 prototype made its maiden flight from the company's facility in Wichita, Kansas; its construction had begun 13 months earlier. For the subsequent flight test programme, experienced personnel were borrowed from the airline Transcontinental and Western Air. On 4 March of that same year, it received type certification, clearing the aircraft to enter civil service, although only six production standard aircraft would be produced that year and deliveries would not commence until 1938. Following the completion of flight testing, Walter Beech personally flew the prototype on numerous demonstration flights; it performed a tour across both the United States and Canada as part of publicity efforts with the goal of driving sales of the type.
Early orders for the type typically came from charter airlines, including those based overseas, as well as a few corporations seeking executive aircraft. Furthermore, as early as January 1939, the US government took an interest in the type, initially to perform photo reconnaissance. Throughout World War II, military orders for the type took precedence over the company's commercial activities. Shortly after the Surrender of Japan, which ended the conflict, military production ceased. Beechcraft transitioned back to full-rate commercial aircraft production by October 1945. Numerous refinements and improvements were incorporated around this time, including revised landing gear, brakes, and tires that, in conjunction with other structural modifications, increased the aircraft's maximum weight capacity.
Early production aircraft were powered either by a pair of 330-hp (250-kW) Jacobs L-6s or 350-hp (260-kW) Wright R-760Es; at the time, these were the only engines available that satisfied the designer's requirements. Many aircraft, such as the D18S variant, were powered by two 450-hp (336-kW) Pratt & Whitney R-985 "Wasp Junior" nine-cylinder radial engines, paired with Hamilton Standardconstant speed propellers. The Model 18 has used a variety of engines and has been subject to a number of airframe modifications to increase both gross weight and speed. At least one aircraft was modified to use 600-hp (447-kW) Pratt & Whitney R-1340 "Wasp" powerplants. With the added weight of about 200lb (91kg) per engine, the concept of a Model 18 fitted with R-1340 engines was deemed unsatisfactory due to the weakest structural area of the aircraft being the engine mounts.
On 10 December 1953, the prototype of the improved Super 18 made its first flight. In 1955, deliveries of the Model E18S commenced; the E18S featured a fuselage that was extended 6in (150mm) higher for more headroom in the passenger cabin. All later Beech 18s (sometimes called Super 18s) featured this taller fuselage, and some earlier models (including one AT-11) have had this modification. The Model H18, introduced in 1963, featured optional tricycle undercarriage. Unusually, the undercarriage was developed for earlier-model aircraft under an supplemental type certificate by Volpar, and installed in H18s at the factory during manufacture. A total of 109 H18s was built with tricycle undercarriage, and another 240 earlier-model aircraft were modified with this.
In November 1969, production of the Model 18 came to an end; the final aircraft, a Model H18, was delivered to Miyazaki Aviation College, Japan, that same year. Through the years, 32 variations of the basic design had flown, over 200 improvement modification kits were developed, and almost 8,000 aircraft were built. In one case, the aircraft was modified to a triple tail, trigear, humpbacked configuration and appeared similar to a miniature Lockheed Constellation. Another distinctive conversion was carried out by Pacific Airmotive to become the PacAero Tradewind, which featured a lengthened nose to accommodate the tricycle nosewheel, and replaced the Model 18's twin tailfins with a single fin arrangement.
Operational history
Beechcraft 18 on floats
Production got an early boost when Nationalist China paid the company US$750,000 for six M18R light bombers, but by the time of the U.S. entry into World War II, only 39 Model 18s had been sold, of which 29 were for civilian customers. Work began in earnest on a variant specifically for training United States Army Air Forces (USAAF) military pilots, bombardiers, and navigators. The effort resulted in the Army AT-7. Further development led to the AT-11 navigation trainer, C-45 military transport, and F-2 (the "F" standing for "Fotorecon", short for "photographic reconnaissance"). The United States Navy (USN) first adopted the Beech 18 as the JRB-1, equivalent to the F-2, followed by the JRB-2 transport; the JRB was initially named the Voyager, but this name did not enter common use, and JRBs were generally called Expeditors like their USAAF counterparts. The first JRB-1 obtained by the USN, bureau number (BuNo) 09771, was converted from the last civilian Model 18 built before production was earmarked solely for the military for the duration of the war. The USN subsequently obtained more Model 18s as the JRB-3 (C-45B), JRB-4 (UC-45F), SNB-1 Kansan (AT-11), SNB-2 (AT-7), and SNB-2C (AT-7C). Existing naval Twin Beeches were subsequently modified into the SNB-2H air ambulance, SNB-2P reconnaissance trainer, and SNB-3Q electronic countermeasures trainer. The United States Coast Guard acquired seven JRB-4 and JRB-5 aircraft from the USN between 1943 and 1947; they were primarily used as utility transports, with one aircraft later converted for aerial mapping and another used for proficiency flying.
After the conflict, the USAAF was reorganised into the United States Air Force (USAF), and its Strategic Air Command had Model 18 variants (AT-11 Kansans, C-45 Expeditors, F-2 Expeditors, and UC-45 Expeditors) from 1946 until 1951. In 1950, the USN still had around 1,200 JRB and SNB aircraft in inventory. From 1951 to 1955, the USAF had many of its aircraft remanufactured with new fuselages, wing center sections, and undercarriages to take advantage of the improvements to the civilian models since the end of World War II. Eventually, 900 aircraft were remanufactured to be similar to the then-current Model D18S and given new designations, constructor's numbers, and USAF serial numbers. The USN had many of its surviving aircraft remanufactured, as well, resulting in the JRB-6, SNB-5, and SNB-5P. The Coast Guard retired its JRBs in 1956 and sold most of them as surplus in 1959, but one was retained by the United States Coast Guard Reserve until at least 1972. With the adoption of the 1962 United States Tri-Service aircraft designation system, the USN's SNB-5 and SNB-5P became the TC-45J and RC-45J, respectively, later becoming the UC-45J as their primary mission shifted from aircrew training to utility transport work. The C-45 flew in USAF service until 1963, the USN retired its last UC-45J in 1972, while the U.S. Army flew its C-45s until 1976. In later years, the military called these aircraft "bug smashers" in reference to their extensive use supplying mandatory flight hours for desk-bound aviators in the Pentagon.
Beech 18s were used extensively by Air America during the Vietnam War; initially more-or-less standard ex-military C-45 examples were used, but then the airline had 12 aircraft modified by Conrad Conversions in 1963 and 1964 to increase performance and payload. The modified aircraft were known as Conrad Ten-Twos, as the maximum takeoff weight (MTOW) was increased to 10,200lb (4,600kg). The increase was achieved by several airframe modifications, including increased horizontal stabilizer angle-of-incidence, redesigned undercarriage doors, and aerodynamically improved wingtips. Air America then had Volpar convert 14 aircraft to turboprop power, fitted with Garrett AiResearch TPE-331 engines; modified aircraft were called Volpar Turbo Beeches, and also had a further increase in MTOW to 10,286lb (4,666kg).
Spar problems
The wing spar of the Model 18 was fabricated by welding an assembly of tubular steel. The configuration of the tubes in combination with drilled holes from aftermarket supplemental type certificate (STC) modifications on some of these aircraft have allowed the spar to become susceptible to corrosion and cracking while in service. This prompted the FAA to issue an Airworthiness Directive in 1975, mandating the fitting of a spar strap to some Model 18s. This led, in turn, to the retirement of a large number of STC-modified Model 18s when owners determined the aircraft were worth less than the cost of the modifications. The corrosion on unmodified spars was not a problem; it occurred due to the additional exposed surface area created through the STC hole-drilling process. Further requirements have been mandated by the FAA and other national airworthiness authorities, including regular removal of the spar strap to allow the strap to be checked for cracks and corrosion and the spar to be X-rayed. In Australia, the airworthiness authority has placed a life limit on the airframe, beyond which aircraft are not allowed to fly.
First production model with seating for two pilots and seven or eight passengers, fitted with Wright R-760E-2 engines of 350 horsepower (260kW), MTOW: 6,700lb (3,000kg) Four built.
Model S18A
Version of Model 18A capable of being fitted with skis or Edo 55-7170 floats; MTOW: 7,200lb (3,300kg)
Model A18A
Version fitted with Wright R-760E-2 engines, MTOW: 7,500lb (3,400kg)
Model SA18A
Seaplane version of Model A18A, MTOW: 7,170lb (3,250kg)
Model 18B
Version powered with 285hp (213kW)Jacobs L-5 engines. Four built.
Model S18B
Version of Model 18B capable of being fitted with skis or floats.
Model 18D
Variant with seating for two pilots and nine passengers, fitted with Jacobs L-6 engines of 330 horsepower (250kW), MTOW: 7,200lb (3,300kg). Twelve aircraft built.
Model S18D
Version of Model 18D capable of being fitted with skis or Edo 55-7170 floats[citation needed], MTOW: 7,170lb (3,250kg)[failed verification]
Model A18D
Variant of 18D with MTOW increased by 300lb (140kg) to 7,500lb (3,400kg).
Model SA18D
Seaplane version of Model A18D, but same MTOW as S18D
Model 18R
Model with Pratt and Whitney R-985-A1 engines with dual-stage blower for increased power at higher operating altitudes[citation needed], 420 horsepower (310kW), seven built, one to Sweden as an air ambulance, six to Nationalist China as M18R light bombers
Model 18S
Nine-passenger pre-World War II civil variant, powered by 450hp (340kW) served as basis for USAAF C-45C
Model B18S
Nine-passenger pre-World War II civil variant, served as basis for USAAF F-2
Model C18S
Variant of B18S with seating for eight passengers, and equipment and minor structural changes
Model D18S
First post-World War II variant introduced in 1945, with seating for eight passengers and MTOW of 8,750lb (3,970kg), 1,035 built
Model D18C
Variant with Continental R9-A engines of 525 horsepower (391kW) and MTOW of 9,000lb (4,100kg), introduced in 1947, 31 built.
Model E18S
A 3-view line drawing of a Model E18S
Variant with redesigned wing and MTOW of 9,300lb (4,200kg); 403 built
Model E18S-9700
Variant of E18S with MTOW of 9,700lb (4,400kg); 57 built
Superseded E18S, MTOW of 9,700lb (4,400kg); 155 built
Model G18S-9150
Lightweight version of G18, MTOW of 9,150lb (4,150kg); one built
Model H18
Last production version, fitted with optional tricycle undercarriage developed by Volpar and MTOW of 9,900lb (4,500kg); 149 built, of which 109 were manufactured with tricycle undercarriage
Military versions
USAAC/USAAF designations
C-45
Six-seat staff transport based on C18S; 11 built
C-45A
Eight-seat utility transport based on C18S; 20 built
RC-45A
Redesignation of all surviving F-2, F-2A, and F-2B aircraft by the USAF in 1948
C-45B
Based on C18S, but with modified internal layout; 223 ordered, redesignated UC-45B in 1943 Equipped with a hatch in the cabin door for aerial photography.
C-45C
Two Model 18S aircraft impressed into the USAAF, redesignated UC-45C in January 1943
C-45D
Designation given to two AT-7 aircraft converted as passenger transports during manufacture, redesignated UC-45D in January 1943
Designation given to two AT-7 and four AT-7B aircraft converted as passenger transports during manufacture, redesignated UC-45E in January 1943
C-45F
Standardized seven-seat version based on C18S, with longer nose than preceding models; 1,137 ordered, redesignated UC-45F
C-45G
AT-7s and AT-11s remanufactured in the early 1950s for the USAF to similar standard as civil D18S with autopilot and R-985-AN-3 engines; 372 aircraft rebuilt
TC-45G
Multiengine crew trainer variant of C-45G; AT-7s and AT-11s remanufactured in the early 1950s for the USAF to similar standard as civil D18S, 96 aircraft rebuilt
C-45H
AT-7s and AT-11s remanufactured in the early 1950s for the USAF to similar standard as civil D18S, with no autopilot and R-985-AN-14B engines; 432 aircraft rebuilt
TC-45H
RC-45J
In 1962, all surviving U.S. Navy SNB-5Ps were redesignated RC-45J
TC-45J
In 1962 all surviving U.S. Navy SNB-5s were redesignated TC-45J
UC-45J
Subsequent redesignation of RC-45J and TC-45J
AT-11 at the Barksdale Global Power MuseumA 3-view line drawing of an AT-11
AT-7 Navigator
Navigation trainer based on C18S, with an astrodome and positions for three students, powered by 450-hp Pratt & Whitney R-985-25 engines; 577 built
AT-7A
Floatplane version of AT-7; six built
AT-7B
Winterised AT-7; nine built
AT-7C
Based on C18S with R-985-AN3 engines; 549 built
AT-11 Kansan
Bombing and gunnery trainer for USAAF derived from AT-7, fuselage had small, circular cabin windows, bombardier position in nose, and bomb bay; gunnery trainers were also fitted with two or three .30-caliber machine guns, early models (the first 150 built) had a single .30-cal AN-M2 in a Beechcraft-manufactured top turret, later models used a Crocker Wheeler twin .30-cal top turret, a bottom tunnel gun was used for tail gunner training, 1,582 built for USAAF orders, with 24 ordered by Netherlands repossessed by USAAF and used by the Royal Netherlands Military Flying School at Jackson, Mississippi.
AT-11A
Conversion of AT-11 as navigation trainer; 36 converted
CQ-3
Conversion of UC-45F, modified to act as drone control aircraft, redesignated as DC-45F in June 1948[citation needed]
F-2s in Alaska, 1941
F-2
Photo-reconnaissance version based on B18
F-2A
Improved version
F-2B
US Navy designations
SNB-1 KansanSNB-2 Navigator
JRB-1
Photographic aircraft, based on the C18S, fitted with fairing over cockpit for improved visibility, 11 obtained, at least one conversion from impressed civil B18S
JRB-2
Light transport, based on the C18S; 15 obtained, at least one conversion from JRB-1, some transferred from USAAF C-45A stocks
JRB-3
Photographic version, similar to C-45B; 23 obtained, some transferred from USAAF C-45B stocks
JRB-4
Utility transport version, equivalent to UC-45F; 328 obtained from USAAF
(Thai: บ.ล.๑) designation for the C-45B and C-45F.
Conversions
PacAero Tradewind
Conrad 9800
Modification increasing the gross weight to 9,800 pounds with a single piece windshield
Dumod I
Executive conversion with Volpar tricycle landing gear, new wing tips, enlarged fight deck and refurbished 6–7 seat cabin with larger windows. Originally named Infinité I. 37 converted by 1966.
Dumod Liner
Stretched airliner conversion. Similar to Dumod I but with forward fuselage stretched by 6feet 3inches (1.91m), allowing up to 15 passengers to be carried. Originally named Infinité II.
Hamilton HA-1
conversion of a TC-45J aircraft
Hamilton Little Liner
Modification of D18S with aerodynamic improvements and new, retractable tailwheel, capable of carrying 11 seats
Hamilton Westwind
Turboprop conversions with various engines
Hamilton Westwind III conversion at an airfield in Tennessee
Hamilton Westwind II STD
Stretched conversion powered by two 840-hp PT6As, and with accommodation for up to 17 passengers
Conversion of Beech D18S/C-45 to five- to 11-seat executive transport with single fin by Pacific Airmotive
Rausch Star 250
Built as C-45F 44-47231, this aircraft was re-manufactured at Wichita by Beech in 1952, to become TC-45G 51-11544. From 1959 Rausch Engineering Inc. of South San Francisco, California, converted N8186H to tricycle undercarriage, using forward retracting main gear from a P-51 and rearward-retracting nose-leg from a T-28, adding a 3ft (0.91m) nose extension, 4ft (1.22m) rear fuselage extension, re-roofed fuselage for increased headroom and enlarged cabin windows. The modifications did not obtain FAA certification despite 58 hours of flight testing, with the aircraft eventually being broken up at Antioch, CA, in 1978.
Conversion of Model 18 with nosewheel undercarriage
Volpar (Beechcraft) Super 18
Volpar (Beechcraft) Turbo 18
Beech Model 18s fitted with the Volpar MkIV tricycle undercarriage and powered by two 705-hp Garrett TPE331-1-101B turboprop engines, flat-rated to 605hp (451kW), driving Hartzell HC-B3TN-5 three-bladed, reversible-pitch, constant-speed feathering propellers
The Beechcraft Model 18 family has been involved in the following notable accidents and incidents:
25 April 1951: Cubana de Aviación Flight 493, a Douglas DC-4 bound from Miami to Havana, registration CU-T188, collided with a U.S. Navy SNB-1, bureau number39939, which was performing a practice instrument approach to Naval Air Station Key West. The collision and ensuing crashes killed all 34 passengers and five crew aboard the DC-4 and all five crew aboard the SNB. The accident occurred at midday, weather was clear with unlimited visibility, and both flight crews had been cleared to fly under visual flight rules, being expected to "see and avoid" other aircraft; the student flying the SNB was wearing view-limiting goggles, but the other SNB crew were not, and were expected to keep watch. Ground witnesses said that neither aircraft took evasive action prior to the collision, and the Civil Aeronautics Board attributed the accident to the failure of both flight crews to see and avoid conflicting air traffic.
19 September 1965: During the India–Pakistan war of 1965, eight people including Chief Minister Balwantrai Mehta of Gujarat, India, were killed when their civilian-registered Beechcraft 18 was shot down southwest of Bhuj by an F-86 Sabre of the Pakistan Air Force, which had concluded that the Indian Army had been conducting reconnaissance of a nearby conflict zone using civil aircraft.
10 December 1967: American soul music singer Otis Redding, four members of his backing band the Bar-Kays, the pilot, and another member of Redding's entourage were killed in the crash of Redding's H18, registration N390R, into Lake Monona on approach to Truax Field in Wisconsin. The National Transportation Safety Board (NTSB) was unable to determine the cause of the crash, noting that the left engine and propeller were not recovered. Trumpet player Ben Cauley, the sole survivor of the crash, subsequently revived the Bar-Kays together with another band member who was aboard a different aircraft.
20 September 1973: American folk rock singer-songwriter Jim Croce, four members of his entourage, and the pilot were killed when their chartered E18S, registration N50JR, crashed into a tree shortly after takeoff from Natchitoches Regional Airport in Louisiana. The NTSB attributed the accident to reduced visibility due to fog, and to physical impairment of the pilot, who had severe coronary artery disease and had run 3mi (4.8km) to the airport. An investigation conducted for a lawsuit against the charter company attributed the accident solely to pilot error, citing his downwind takeoff into a "black hole" of severe darkness, causing him to experience spatial disorientation.
26 September 1978: Air Caribbean Flight 309, an air taxi flight by a D18S, registration N500L, crashed on approach to Isla Verde International Airport in Puerto Rico, killing the pilot and the five passengers aboard the aircraft and causing substantial property damage and injuries to bystanders on the ground. The pilot could not communicate with approach control and was following directions relayed by local tower controllers, who told the pilot to make a turn and maintain separation from a Lockheed L-1011 that was overtaking the flight, but the pilot did not turn, and the D18S passed underneath and very close to the L-1011. Both the NTSB and a U.S. District Court ruling attributed the crash to the D18S pilot's failure to correctly follow visual flight rules and air traffic control instructions to maintain separation from the much larger L-1011, causing a loss of aircraft control due to wake turbulence. A contributing factor was the pilot's difficulties in communication with controllers.
4 July 1987: Ten people, including all then-current members of The Montana Band, were killed when the pilot of their chartered D18S, N132E, failed to clear a hillside near Lakeside, Montana, while performing a flypast of the venue where the band had performed earlier. The pilot performed an "abrupt" climb and performed a "hammerhead stall" maneuver, reversing direction and entering a dive. The accident was attributed to the pilot's poor judgment and failure to maintain altitude during unauthorized attempted aerobatics.
'JA5174' – H18 the final Beech 18 produced (c/n BA-765), delivered January 1970 to Miyazaki Aviation College, Japan. In use until 1988, now preserved at the College, Miyazaki Airport.
12"Fact Sheet: Beech C-45H Expeditor". National Museum of the United States Air Force. Wright-Patterson Air Force Base, Dayton, Ohio. Retrieved 5 August 2017.
↑"Fact Sheet: Beech AT-11 Kansan". National Museum of the United States Air Force. Wright-Patterson Air Force Base, Dayton, Ohio. Retrieved 5 August 2017.
↑Bauschspies, James S. and William E. Simpson, "Research and Technology Program Perspectives for General Aviation and Commuter Aircraft", NASA Contract NASW-3554 for NASA, Sept. 1982, N83-17454#. Retrieved: 18 December 2014. (In particular, see: Table 2.4 "COMMUTER CARGO FLEET IN 1981 - TOP TEN AIRCRAFT MODELS - NUMBER IN FLEET," which notes Beech 18 units are more than the next two aircraft combined (Convair 500/680 and Douglas DC-3), and more than the next three general aviation aircraft combined.
↑"Beech 18". Federal Aviation Administration. Archived from the original on 3 July 2018. Retrieved 5 August 2017.
↑Croce v. Bromley Corporation,623F.2d1084(5th Cir.1980)("The plaintiffs' expert medical witness testified at length that spatial disorientation resulting from the pilot's taking off into a "black hole" was the cause of the crash. See n.12, supra. This theory was buttressed by the testimony of Asher Vandenberg, a commercial, multiengine pilot with instrument ratings.").
↑In Re N-500L Cases,517F. Supp.825(D.P.R.1981)("The Court finds that the pilot of N-500L was responsible, in the VFR flight conditions which existed on the night of the accident, to visualize and to avoid wake turbulence of EAL 75. By continuing into the flight path of EAL 75 the pilot of N-500L was negligent and this negligence was a proximate cause of the crash.").
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