1971_美国_AAR7106.pdf

8 A T I O N A L T R A N S P O R T A T I O N S A F E T Y B O A R D

AIRCRAFT ACCIDENT REPORT

JETCO AVIATION, INCORPORATED

SHORT BROTHERS & HARLAND, LTD.

SKYVAN SERIES 3 (SC-7), N21CK

WASHINGTON NATIONAL AIRPORT

WASHINGTON, D.C.

JULY 2,1970

〔图〕V(11A.1\n NATIONAL TRANSPORTATION SAFETY BOAPD Washington, D. C. 20591

REPORT NUMBER: NTSB-AAR-71-6

SA- None

File No. 3-0594

AIRCRAFT ACCIDENT REPORT

JETCO AVIATION, INCORPORATED

SHORT BROTHERS & HARLAND, LTD.

SKYVAN SERIES 3 (SC-7), N21CK

WASHINGTON NATIÚNAL AIRPORT

WASHINGTON, D.C.

JULY 2, 1970

Adopted: January 13, 1971

NATIONAL TRANSPORTATION SAFETY BOARD

Washington, D. C. 20591

REPORT NUMBER: NTSB-AAR-71-6

NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D. C., 20591 AIRCRAFT ACCIDENT REPORT

JETCO AVIATION, INCORPORATED SHORT BROTHERS & HARLAND, LTD. SKYVAN SERIES 3 (SC-7), N21CK WASHINGTON NATIONAL AIRPORT, WASHINGTON, D. C. JULY 2, 1970

TABLE OF CONTENTS

File No. 3-0594

NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D. C. 20591 AIRCRAFT ACCIDENT REPORT

Adopted: January 13, 1971

Jetco Aviation, Incorporated Short Brothers & Harland, Ltd. Skyvan Series 3 (SC-7), N21CK Washington National Airport, Washington, D. C. July 2, 1970

SYNOPSIS

At approximately 10:48 a.m. eastern daylight time on July 2, 1970, Short Brothers & Harland, Ltd., Skyvan Series 3, N21CK, operated by Jetco Aviation, Inc., Washington, D. C., as air taxi cargo flight, Flight 106, crashed during a VOR approach to Washington National Airport. The aircraft was demolished but did not burn. Both crewmembers received fatal injuries. There were no passengers.

According to witnesses, the aircraft was first visible to them, through fog and haze, when it was 700 to 800 feet above and about one-half mile out from the threshold of Runway 15.

Shortly after the aircraft came into view of the witnesses, it nosed down and rolled left until the wings were nearly vertical. The nosedown angle steepened progressively until it reached 45° or more. The aircraft struck the water of Roaches Run in this attitude, cartwheeled onto the right wingtip and sank in water 12 to 15 feet deep about 1,800 feet north of the threshold of Runway 15.

The Board determines that the probable cause of this accident was the loss of effective elevator control due to the forward shift of improperly secured cargo when the aircraft was placed in a steep nosedown attitude during a landing approach in reduced visibility conditions.

As a result of this investigation the Board recommends that:

The Federal Aviation Administration (FAA) take the necessary action to instruct all air taxi cargo operators to stow and secure their cargo in accordance with the provisions of Part 135,117 of the Federal Aviation Regulations and the manufacturer's specifications for the aircraft involved.

As a result of information obtained during this investigation, Short Brothers & Harland, Limited, Belfast, Northern Ireland, issued two Service Bulletins:

Service Bulletin No. 27-53 - Flying Controls:

To introduce a re-designed fork end fitting on the Anti-Up Float Spring Pot in Elevator Control Circuit.

• 2 -

Service Bulletin No, 25-56 - Equipment & Furnishings:

To fit guards at rear of list and 2nd Pilot's Seats.

INVESTIGATION

Jetco Aviation, Inc., Skyvan, Flight 106, N21CK, was completing the last leg of a point-to-point cargo flight that originated at Washington, D, C., at approximately 1730 1/ the previous day. Jetco Flight 106 was scheduled to depart John F. Kennedy International Airport (JFK), New York, at 0600, July 2, 1970; however, because of en route delays, departure from JFK was not until 0856. The flight was made in accordance with a visual flight rules (VFR) flight plan until it arrived in the vicinity of Atlantic City, New Jersey. The crew then air-filled an abbreviated instrument flight rules (IFR) flight plan and the flight was cleared to the Washington National Airport.

As Flight 106 approached Washington, D. C., the crew received clearance for a WOR 2/ approach to Runway 15 and at 1047:25, the tower controller at Washington National Airport (DCA) cleared the flight to land. He advised the crew that the surface wind was from 200° at 5 knots, and asked them if they had the airport in sight. At 1047:35, the crew replied, "Tower, not yet, we've got the Pentagon here." At 1047:55, the crew reported, "106 has the runway." This was the last communication from the aircraft and, 5 to 10 seconds later, the local controller and his assistant saw the aircraft at an estimated altitude of 500 feet. It was in a steep, diving bank to the left when it disappeared from their view.

The crewmembers were properly certified and medically qualified for the performance of their duties. The copilot, a part-time pilot, was making his first trip with Jetco. The duty time for both pilots the preceding 24 hours was 18:18 hours. (For details, see Attachment 2.)

The aircraft was properly certified for the flight, N21CK, serial No. S11858, was a cargo configuration of the Skyvan Series 3, Model SC-7, Variant 200. (For details, see Attachment 3.)

The maintenance records for the aircraft show that it had met the airworthiness standards in all maintenance categories except one; at the time of the accident, the aircraft had accumulated 111:86 hours since the last 100-hour inspection.

The aircraft fuel tanks were filled with jet fuel prior to the departure from John F. Kennedy International Airport.

The cargo floor in this type of airc:aft contains 70 cargo-restraint fittings. Each fitting is designed for a load of 4,000 pounds. The cargo hold is 18 feet

· 3 ·

7 inches long, 6 feet 6 inches wide, and 6 feet 6 inches high. There are seven seat-retaining rings on each side of the cargo compartment, which are not designed to restrain cargo. The front and rear rings are single and all the rest are double rings. Following the accident, tensile strength tests of these ring assemblies were made by the National Bureau of Standards. The tests revealed that failure occurs along the longitudinal axis of the bracket when a load of 1,339 pounds is applied. Failure occurs 45° to the longitudinal axis when a load of 400 pounds is applied.

The driver who delivered the New York cargo consignment to the aircraft later assisted the crew in loading some of the h. ivier boxes. The New York cargo weighed 2,766 pounds and was contained in 67 cartons and boxes. The driver noticed that some cargo had been previously loaded in the forward section of the cargo compartment. This cargo weighed 611 pounds and was contained in 29 boxes and cartons that were loaded on board at Boston. The driver said that most of the cargo he delivered was loaded on a "plywood" sheet, directly over cargo rollers, in the forward section of the cargo area, and the remainder was wedged along the sides. He saw the crewmembers tie down the cargo. He said they used one web-type n'lon strap. One end of this strap was secured at a forward point on the left sidewall of the cabin. The other end was placed around the rear of the cargo and secured to a point on the right rear sidewall of the cabin. A crewmember then used a ratchet to tighten the strap at the right side point.

The 1029 surface weather observations, taken at Washington National Airport prior to the accident, were:

Estimated ceiling 8,000 feet overcast, visibility 2₂ miles, fog, haze; wind from 200°. 5 knots, altimeter setting 29,94.

The 1057 reported Washington National Airport weather observation was as follows:

Estimated ceiling 8,000 feet overcast, visibility 2½ miles, fog, haze; temperature 77° F., dew point 13° F., wind from 180°, 5 knots, altimeter setting 29.94.

Runway 15 at Washington National Airport is 5,212 feet long and 200 feet wide. Runway 15 has high-intensity runway lights, runway end identifier lights, and a Visual Approach Slope Indicator (VASI). All field lights were on at full brightness.

The airport elevation is 15 feer m.s.l. 3/ The distance from the end of Runway 15 to the Pentagon is 0.8 nautical miles. (See Attachment 4.)

The flightpath of the aircraft at impact was approximately 50° magnetic. The center point of the wreckage area was located about 240 feet from the nearest shore under 12 to 15 feet of water. Approximately 95 percent of the aircraft was

3/ Mean sea level.

-4-

salvaged from a circular area in the water about 170 feet in diameter. Missing items included the copilot's seat, some instruments, both flight control columns, and some small pieces of fuselage skin.

All of the recovered trim control cables sustained tension fallures. All of the turnbuckles were intact and safety wired. The elevator trim actuator was 1° down (1° noseup trim). The total trim available was 5° noseup and 4° nosedown.

The right wing was recovered practically intact but without the engine and nacelle. The aileron and two sections of flap were attached to the wing. The flap was partially extended. Measurements of the flap actuator in the aircraft were compared with measurements of a similar aircraft with the flaps in various positions. These comparisons indicated that the flaps on Flight 106 were extended 50° (full down) at impact. The right flap impact mark on the fusclage measured 50°. Both wing flaps are operated by one actuator, and the position of one flap corresponds mechanically to the position of the other flap.

The left wing was recovered in two pieces. One piece, the inboard quarter behind the main spar, had a section of flap attached. The other piece comprised the remainder of the wing, less the aileron and the engine. The left engine had separated from the wing at the main mounts.

The right side of the empennage was essentially intact. The left vertical stabilizer, left rudder, and left side of the elevator had separated from the empennage, but were recovered.

The nose section, the pilot's half of the cockpit, and the entire left side of the fuse!age were fragmented. The right side of the fuselage, including the top of the copilot's entrance door, showed four slashmarks. The pilot's entrance door, the ditching hatch, and the rear cargo doors were recovered. The cargo floor was examined, and all cargo restraint rings were found to be intact except for two on the left side where the floor was broken. None of the cargo restraint rings has cargo strap hooks attached, nor was there any evidence that any had been attached. Four cargo rollers and a k-inch thick pressed-wood pallet were recovered. Two of the rollers were each 10 feet long and two were 5 feet long.

Seven nylon cargo straps were aboard the aircraft at impact. These were recovered and none of the straps was broken. Cargo nets were not used on this flight.

One cargo strap hook had a single fuselage seat-storage ring attached and another strap hook had double fuselage seat-storage rings attached. These two straps were wrapped about each other when salvaged.

Of the five remaining straps, one that was compactly rolled was found lodged under the pilot's seat. The other four were loose with all locking and ratchet mechanisms and hooks intact.

The engines and propellers were examined under NISB cognizance at the Aire-search plant at Phoenix, Arizona. This examination showed that both engines were rotating at impact and that both propellers were set for landing approach power.

• 5 -

No evidence was found that would indicate any preimpact malfunction or failure of the aircraft systems that could be related to the cause of the accident.

The entire flight control system was recovered, including all the push-pull rods and rod end fittings in the empennage. All breaks were typical of breaks resulting from gross bending and tension overloads. The elevator anti-up float spring pot assembly was still attached to the fuselage attaching structure. However, the clevis end of this assembly was separated in the threaded section with the clevis end attached to its respective bell crank. The fractured ends showed preimpact fatigue cracks on the top and bottomsides through approximately 20 percent of the cross-sectional area. The cracks were typical of fairly low cycle, high-stress type fatigue propagation. This assembly supplies artificial "feel" of elevator control force to the pilot in the last 30 percent of up-elevator travel, and its eventual failure would not affect the controllability of the aircraft.

The accident was nonsurvivable. Autopsies showed that both pilots sustained fatal injuries as the result of impact.

The maximum certified takeoff and landing weight for the aircraft is 12,499 pounds. The following computations relate to the weight and balance of N2ICK on departure from JFK, using actual weights:

The aircraft was about 1,600 pounds overweight for takeoff; however, the manufacturer states that "experience has shown that this in itself would not be dangerous although performances after an engine failure would be marginal."

The maximum trimmable center of gravity limit forward is 10 percent of the mean aerodynamic chord (HAC) ahead of the forward center of gravity limit. Beyond this point, the aircraft is uncontrollable. The computed center of gravity for the aircraft at takeoff was 2.30% forward of the forward limit. The manufacturer states, "Although wrongly loaded this is still well within the trimmable range,"

ANALYSIS AND SUMMARY

Investigation of the aircraft, engines, systems, and aircraft records indicated that there were no mechanical malfunctions or failures of the aircraft that could be related to the probable cause of the accident.

$$ \sim 6= $$

Air Traffic Control functions were properly executed as they related to Flight 106, and there was no evidence of any equipment or navigational facility malfunctions.

The reported visibility was 2k miles with fog and haze; however, there is evidence that the crew did not see Runway 15 until the aircraft had approached to within about one-half mile, or less, from the end of the runway. They did not have the runway in sight in the vicinity of the Pentagon, which is 0,8 nautical mile from the end of the runway.

The landing minima on this approach to Runway 15 is ceiling 700 feet and one mile visibility, requiring that the pilot maintain a minimum m.s.l, altitude of 715 feet until the runway is in sight. This woul, account for the high approach altitude which ground witnesses observed and estimated to be between 700 and 800 feet,

The cargo floor of the aircraft was adequate for cargo tiedown; however, the cargo was not secured in accordance with approved procedure. There were no cargo nets aboard. None of the cargo straps was anchored to the floor tiedown rings either fore and aft or from side to side over the load. (See Attachment 8.) The cargo tiedown straps used were attached to a forward sidewall seat-retaining ring, placed around the rear of the load, and attached to an aft sidewall seat-retaining ring.

Assuming that the pilot was flying at about 700 feet altitude at one-half a mile out, it would be necessary for him to descend at a rate of at least 2,100 feet per minute (f.p.m.), on a glide slope of about 13° to be in proper landing position over the runway. A normal rate of descent for a standard landing glide slope of 3° is about 400 f.p.m.

A STOL aircraft, such as the Skyvan, is capable of making a steep glide slope final approach to a runway due to its high lift features. However, in order to make good a 13° glide slope, the deck angle of the aircraft must be changed drastically. Initially, the power is reduced to idle and the pilot then lowers the flaps to full down. This maneuver, which combines a steep nosedown attitude, full flaps, and the drag from the propellers would have caused forward longitudinal forces to be exerted on the 96 boxes and cartons in the cargo hold. If this cargo were not properly restrained from these forward forces, it would progress forward, moving the aircraft center of gravity accordingly. As the center of gravity moved beyond its forward controllable limit, effective elevator control would be lost. (See Attachment 5.) Witness descriptions of the aircraft's nose dropping down through a 45° angle indicate that a progressive control loss of this type occurred.

Probable Cause

The Board determines that the probable cause of this accident was the loss of effective elevator control due to the forward shift of improperly secured cargo when the aircraft was placed in a steep nosedown attitude during a landing approach in reduced visibility conditions,

• 7 -

Recommendations

As a result of this investigation the Board recommends that:

The Federal Aviation Administration (FAA) take the necessary action to instruct all air taxi cargo operators to stow and secure their cargo in accordance with the provisions of Part 135.117 of the Federal Aviation Regulations and the manufacturer's specifications for the aircraft involved. Corrective Actions

As a result of information obtained during this investigation, Short Brothers & Harland, Limited, Belfast, Northern Ireland, issued two Service Bulletins.

Service Bulletin No. 27-53 - Flying Controls:

To introduce a redesigned fork end fitting on the Anti-Up Float Spring Por in Elevator Control Circuit. (See Attachment 6.)

Service Bulletin No. 25-56 - Equipment & Furnishings:

To fit guards at rear of 1st and 2nd Pilot's Seats. (See Attachment 7.)

BY THE NATIONAL TRANSPORTATION SAFETY BOARD:

/s/ JOHN H. REED Chairman

/s/ OSCAR M. LAUREL Member

/s/ FRANCIS H. MCADAMS Member

/s/ LOUIS M. THAYER Member

/s/ ISABEL A. BURGESS Member

January 13, 1971

ATTACHMENT 1

INVESTIGATION AND HEARING

1. Investigation

The Board received notification of the accident at 1102 e.d.t. on July 2, 1970. The Investigator-in-Charge was dispatched immediately to the scene from the Washington Field Office at Dulles International Airport, with technical assistance from Washington, D. C., Working groups were established for operations, witnesses, air traffic control, structures, powerplants, aircraft and maintenance records, systems, and human factors. Parties to the investigation were Jetco Aviation, Inc., the Federal Aviation Administration, Short Brothers & Harland, Ltd., the Garrett Corporation, and Airesearch Manufacturing Company. The on-scene phase of the investigation was completed in about 9 days due to the need for underwater salvage operations. Tests and failure analysis of specific aircraft parts were conducted at the Safety Board headquarters and at the National Bureau of Standards. The engines were examined at the Airesearch Mfg. Co, plant at Phoenix, Arizona.

2. Hearing

There was no public hearing.

3. Preliminary Reports

An interim report of investigation summarizing the facts disclosed by the first phase of the investigation was published on September 14, 1970.

Attachment 2

1. PILOT HISTORY

2286 1988年11月23日

Attachment 3

NT58 Færm 61284 PAGE 7

$$ \frac{c_1}{c_2} = \frac{c_1}{c_2} $$

NATIONAL TRANSPORTATION SAFETY BOARD

〔图〕ATIONAI)ARDSAFETY\n

DEPARTMENT OF TRANSPORTATION

WASHINGTON, D.C. - 20591

Safety Information

For Release:

SB 70-69

(202) 382-7373

Office of the Chairman

ADVANCE For

PM Newspapers

Monday, Sept. 14, 1970

The National Transportation Safety Board released today the attached preliminary report of its investigation of the fatal crash of a Deteo Aviation, Inc. Short Skyvan on final approach to Washington National Airport last July 2. The cargo flight accident took the lives of both crewmembers aboard.

The Safety Board's preliminary reports of major accidents make public the known accident facts on an interim basis while its investigation continues. Additional or revised information and the formal finding of probable cause will be incorporated in the Board's final accident report.

转转者转转

AIRCRAFT ACCIENCE PRELIMINARY REPORT

JETCO AVIATION, INCORPORATED

SHORT BROTHERS & HARLAND, LTD.

SKYVAN SERIES 3 (SC-7), N210K

WASHINGTON NATIONAL AIRPORT,

WASHINGTON, D. C.

JULY 2, 1970

NATIONAL TRANSPORATION SAFETY ROARD

WASHINGTON, D. C.

AERCRAFT ACCIENT PRELIMINARY REPORT

JKWO AVIATION, INCORPORATED SHIGHT BROTHERS & HARLAND, LTD. SKYVAN SERIES 3 (SC-7), N21CK, WASHJNGTON NATIONAL AIRPORT, WASH JGTON, D. C. JULY 2, 1970

NOTE: This report covers the facts, circumstances, and conditions of the accident as they are known to this date. It is released by the Board in order to provide as much information as possible to the aviation industry and the public on an interim basis, pending completion of the investigation and the issuance of a formal Board report. The information herein is preliminary in nature and subject to change in light of additional disclosures that may be made as the result of the Board's continuing investigation of this accident.

NATIONAL TRANSPORTATION SAFETY BOARD

WASHINGION, D. C. 20591.

Flle No. 3-(19)4

NATIONAL TRANSPORTATION SAFETY BOARD

AJRCRAFT ACCIENT PRILIMINARY REPORT

Aopted: August 26, 1970

Jetco Aviation, Incorporated Short Brothers & Harland, Ltd. Skivan Series 3 (SC-7), N21CK Washington National Airport, Washington, D. C. July 2, 1970

SYNOPSIS

On July 2, 1970, Short Brothers & Harland, Ltd., Skyvan Series 1, RICK, operated by Jeico Aviation, Inc., Washington, D. C., as air taxi, cargo flight Flight 106 from John F. Kennedy International Airport, New York, so Washington National Airport, Washington, D. C., crashed at approximate 1048 eastern daylight time during a VOR approach to Highway 15 at Washington National Airport. The aircraft was demolished but did no burn. Both crewmembers received fatal injuries. There were no paisengers.

Witnesses on the ground saw Flight 106 approach the airport for a Landing, on Runway 15. One witness described the final manuvers of the draft as a left clip for 200 to 300 feet, followed by a steep, noce-down turn to the left, after which, he lost sight of the aircraft as it disappeared below the trectops.

The manufacturers described by the witness begin less than one-hard of a mile from the approach end of Runway 15, and the dirraft erached in Rouches Run Lagoon, one-quarter of a mile northwest of the airport. Between the approach paths for Runways 15 and 18.

The aircraft came to rest on a heading of 0.20°. Fragmentation of the intercept was extensive but all major aircraft components were finied to a circle approximately 170 feet in diameter, covered by water about 15 feet deep.

There were no injuries to persons other than the crew, and no dam- type to property other than the aircraft and its cargo.

1. INVESTIGATION

1.1 History of Ta. Flight

Jeteo Avixibon, Inc., Skyvan, Flight 106, N21CK, was completing

→ 24 →

the last leg of a flight that originated at Washington D. C., at approximately 1/3, L'July $^{1}$, 1970, as Jetco Flight 101. Jetco Flight 106 was reacubled to depart John F. Kennedy International Airport, New York, at 0600, July 2, 1970; however, because of on route delays, it did not depart JFK until 0856. Departure and the initial part of the flight were in accordance with a visual flight rules (VFR) flight plan.

At 09%, the new contacted Atlantic City, New Jersey, department control and air-filed an abbreviated IPR 2/flight plan. The Flight was cleared to the Washington National Airport from its position via direct to Atlanta City, Victor Airway 44 to Kenton, Victor 16 to North Beach, direct Washington, to climb to and maintain 6,000 feet, and to contact the New York Communication Center. The crew read back the clearance correctly. As Flight 106 approached Washington, D. C., the crew received clearance for a VOR 3/ approach to Runway 15. At 106, the pilot contacted the Washington (DCA) Tower controller on 219.1 MHz and reported that he was on a VOR approach for Runway 15. This communication was acknowledged by the controller.

At 1047:25, the controller cleared the flight to land on Runway 15. He also informed the crew that the surface wind was from 200° at 5 knots, and asked them if they had the airport in sight yet. The reply was, "...not yet, we've got the Pentagon here." At 1047:55, the crew advised the controller, "106 has the runway." This was the last communication from the aircraft. Five to ten seconds later, the aircraft was observed by the local controller and his assistant. It was at an altitude of about 500 feet and in a steep, left-wing-down bank from which it noased down and disappeared behind trees about one-quarter of a mile west of the approach end of Runway 18. These final menuvers were vitnessed by many people on the ground, some of whom were pilot: was, thing: clearance to take off from Runways 15 and 18 at the Washington National Airport. One of these pilots said that when the Skyvan came into a light, it was at an estimated altitude of 300 feet and slightly left of the extended centerline of Runway 15. He said that immediately thereafter it commenced a nosedown left slip for 300 to 300 feet, and rolled to the left to a wings-vertical attitude. At the same time, he saw the nose drop at an increasing rate, to an angle about 15° before the aircraft was lost from his view due to trees.

1. All times used herein are eastern daylight, based on the 24-hour clock.
2. Instrument flight rules.

1. Very High Frequency omit-directional range. The landing minima for a VOR approach to Runway 15 are 700 feet ceiling and 1 mile visibility for propelle, - iriven aircraft.

· 3-

The aircraft crashed into the waters of Roaches Run. Initially, the left wingtip and nose contacted the water while the aircraft was in an estimated 15° to 60° dive, with the wings nearly vertiled. Following the initial contact, the aircraft carwheeled onto the right wingtip and disintegrated, as it sank in 12 to 15 feet of water. The initial impact point was about 1,800 feet north of the threshold of thuviy 15. The cargo, which consisted of 96 cardboard and wooden box-and cartons of varying sizes and weights, was broken up and scattered over a triangular area from the impact point to the shoreline of the tagoon, a distance of about 400 feet.

1.2 Injuries to Persons

The two cremembers were fatally injured. There were no pasremgers.

1.3 Damage to Aircraft

The orrer of was demolished by impact.

1.4 Other Dunige

There was no other damage.

1.3 Crow Information

The Captain

Captein am John Weihs, Jr., aged 46, began flying for Jeteo Avition, Inc., on June 17, 1970. He held Airline Transport Pilot Certificate No. 53714, issued on June 2, 1967, Commercial Pilot Rating, and Flight Instructor Rating and type ratings for the 11-3, Convoir 310/310, C.40, and Lear 23/24 aircraft. He had flown a total of 10,772 hours, including 107:58 in the Skyvin, and he total multening the time was 9,772:00 hours. His flight time in the last 90 days was 9310 hours, of which 7:30 hours were flown during the preceding 24-hour period.

It is most recent first-class medical certificate was issued June 10, 1990, with no limitations or waivers.

The Coplot

Robert Gilmour Williams, aged 35, was on his first trip with Jeteo, no a part time of lot. He held Commercial Pilot Certificate No. 1718403, Feuud on May 3, 1968, with ratings in airplane, single and multi-� in the land, instrument, and flight instructor. His total flight time was 860.006 has ra, of which 7:30 hours were in the Skyvan. He had flown 7:30 hours in the last 24-hour period. His total multi-engine time was 13:12 hours. A. First-class medical certificate, issued to him on December 2, 1969, had no limitations.

Duty time for both pilots in the preceding 24 hours was 18:18 n.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.m.

1.6 Aircraft Information

N21CK, serial. No. EHL858, was a cargo configuration of the Sky-Von Series 3, Model SC-7, Variant 200, manufactured by Short Brother & Harland, Ltd., of Belfast, Ireland. A standard airworthiness certificate was issued on June 18, 1969. The aircraft was owned by the Union Bank of Los Angeles and was operated by Jetco on a lease which started June 16, 1970. The last annual inspection was conducted on June 13, 1970, and the aircraft had been flown a total of 11:86 hours since that time. The total aircraft operating time was 701:0 hours.

The aircraft was equipped with two Garrett Airesearch turbo-prop engines, model TFH331-2-201A. The left engine had accumulated a total of 701:0 hours and the right engine, 1183:4 hours. The propellers were Hartzell HC-H33-N-5C/T reversible.

Maintenance records were examined. This examination indicated that the aircraft was properly maintained and airworthy.

The maximum certified takeoff and landing weight for the aircraft is 12,199 pounds. The following computations relating to the weight and balance of N21CK on departure from JFK were made using the actual weights.

The loading of the aircraft for the last flight segment was covered by a driver who delivered the New York cargo consignment to the aircraft and later assisted the crew in loading some of the bevier boxer, "the driver noticed that some cargo had been previously loaded in the forward section of the cargo compartment, like said that most of the cargo he delivered was loaded on a "plywood" sheet, directly over cargo rollers, in the forward section of the cargo area, and the remainder was wedged forward and along the sides. If observed the rewembers the down the cargo with one web-type nylon strap that was secured at some forward point on the left sidewall of the cabin. The strap was placed around the rear cargo, and its other end was secured to a point or the right rear sidewall of the cabin. A crewmember then lightened the strap at the right side point by using a ratchet-type device.

$$ = 5 = 1 $$

1.7 Meteorological Information

The 1000 surface weather observations, taken at Washington National Airport pr.or to the accident, were:

Not mated selling 8,000 feet overcast, visibility 2.4 miles, top, has; wind from 200°, 5 knots, altimeter setting 29.94.

The 1057 reported Washington National Airport weather observation was as follows:

Estimated ceiling 8,000 feet overcast, visibility 2½ miles, fog, have; temperature 77° F., dev point 73° F., wind from 180°, 5 knots, altimeter setting 29.94.

Ground vitnesses described the visibility as "low with haze and smoke,"

1.8 Mids to Navigation

The were no reported difficulties with any navigation facilities.

1.9 Communizations

There were no reported communications difficulties.

1.10 Her stroge and Ground Facilities

Minary 15 at Washington National Airport is 5,212 feet long and (10) feet side. It is served by high-intensity runway lights, runway end identifier lights, and Visual Approach Slope Indicator (VASI) lights. All field lights were reported to be on at full brightness.

The airport elevation is 15 feet n.s.1. 4/

1.31 Flight Reonler

Flight or voices recorders were not installed aboard the airera't and none was required by regulation.

A.G. Aircraft kreckage

The aircraft was intact upon initial contact with the water. The Pliphipath at impact was approximately 50° magnetic, and the center of the rockage area was located about 240 foot off shore.

h/ Mean sea lovel.

$\therefore f(x)$

Most of the wreckage was confined to a circular area about 170 feet in diameter. All major components of the aircraft were salvaged. The copilot's sent, some instruments, both flight control columns, and some small pieces of fuselage skin were not recovered.

Structure

All trim control system turnbuckles were intact and properly affected. The elevator trim actuator was 1° down (1° noseup trim). This was confirmed by comparing the measurements of the actuator with that on a 6:mile aircraft. Total trim available was 5° noseup and 4° nosedown.

The right wing was recovered practically intact but without the engine and nacelle. The leading edge near the wingtip was buckled in the direction of the trailing edge. The aileron and two sections of flap were attached to the wing. The flap was partially extended. Measurements of the flap actuator in the aircraft were compared with measurements of a similar aircraft when the flaps were in various positions. These comparisons indicated that the flaps on Flight 106 were extended 50° (fuli down) at impact. The right flap impact mark on the fuselage measured 50°, Both wing flaps are operated by one actuator, and the position of one flap corresponds mechanically to the position of the other flap.

The left way was recovered in two pieces. One piece, the in-board quarter behind the main spar, had the flap attached. The other piece comprised the reainnder of the wing, less the alleron and the engine. The left engine had separated from the main mounts.

The two main landing gears and the nose gear were recovered. The right gear was still in place on the mount at the side of the passage; however, the other two landing gears were broken free of their mounts.

The right side of the empenage was essentially intact. The left vertical stabilizer, left rudder, and left side of the elevator repurated from the aircraft, but were recovered.

The nose section, the pilot's half of the cockpit, and the entire left side of the fuselage were fragmented. The right side of the fuselage, including the top of the copilot's entrance door, shoved four slash works. The pilot's entrance door, the ditching hatch, and the cover cargo doors were recovered. The cargo floor was examined and�. Cargo restraint rings were found to be intact except for two on the left side. Scene of the cargo restraint rings had cargo strap in seks attached, ncr was there any evidence that any had been attached.

“1-

Four cargo rollers and a $1/2$-inch thick pressed wood pallet were recovered. 'Two of the rollers were each 10-feet long and two were 5-feet long.

The seven nylon cargo straps aboard the aircraft, at impact, were recoverel. None of the straps was broken.

One cargo strap hook had a single fuselage seat-storage ring attached. Another strap hook had double fuselage seat-storage-claps attached. These two straps were wrapped about each other when salvaged. According to the manufacturer's representatives, seat-storage rings are not designed for use as cargo tie-down rings.

The cargo floor in this type of aircraft contains 70 cargo restraint fittings. Each fitting is designed for a load of 4,000 pounds. There are seven seat-storage rings on each side of the cargo compartment. The cargo hold is 18 feet, 7 inches long, 6 feet, 6 inches wide, and 6 feet inches high.

Poverplants

Left Engine

The left engine was broken into two pieces. The break occurred approximately 12 inches forward of the parting line between the gear box/compressor casting and the hot section of the engine. One left propeller blade was whole, with leading edge nicks and rouges. The second blade was broken off approximately 14 inches from the hub centerline, The third blade was broken off diagonally 26 inches to 36 inches from the hub centerline. The propeller was separated from the engine at the flange bolts. The dome and pitch change mechanism was separated from the propeller at the threaded area.

Right. Engine

The right engine was complete in the nacelle and the propeller was still attached. The propeller blades were bent, t rated , and gouged on the leading edges. One blade tip was broken off. The done assembly was separated from the hub and the threads were stripped.

An examination of the engines and propellers by personnel at the Airesearch plant in Phoenix, Arizona, showed that both engines were rotating at impact and that both propellers were set for landing approach. power,

-8-

Systems

No evidence was found that would indicate any preimpact malfunction or failure of the aireraft systems.

1.13 Fire

There was no fire.

1.3.1 Survival Aspects

The accident was nonsurvlvable. Autopsies showed that both pilots sustained fatal injuries as the result of impact.

1.15 Continuing Investigation

The investigation of this accident is continuing.

BY THE NATIONAL TRANSPORTATION SAFETY BOARD:

/s/ JOHN H. REED Chairman

/s/ OSCAR M. LAUREL Member

/s/ FRANCIS H. MCADAMS Member

/s/ ISABEL A. BURGESS Member

Louis M. Thayer, Member, was not present and did not participate in the adoption of this report.

August 26, 1970.

〔图〕Witnessess0w1234CratmerTewnof he9>yCWhite & Malaveyn1u>3004Chnst>BazerKBRLEAWKrugerNO AEA--14043M[HR:AL56Compbel1CRettin Attachment 5

SKYVAN - N21CK

ACCIDENT AT WASHINGTON, D. C.

Note on Weight and Balance

Short Brothers & Harland Ltd., Belfast, Ireland, manufacturers of SKYVAN N21CK, prepared an analysis of the weight and balance conditions involved in the crash of Flight 106. The report of this analysis contains the following computed conditions:

Estimate of effect of cargo shift

Assume main cargo package becomes dismantled due to acceleration caused by deceleration of aircraft and moves as predicted.

After assumed cargo shift

The aircraft was now down to 13221 lb. and the amount of overweight was 721 lb. which would scarcely have been noticeable.

With a CG arm of 0.012 ft, the CG was 0.833 - 0.012 = 0.821 ft. (9.85 ins.) forward of the normal forward limit or, $\frac{0.821}{5.833} \times 100 = 14.1\%$ SMC forward of forward limit. This is outside the trimmable forward limit which is 10% SMC forward of the normal.

Attachment 6

SHORTS

SERVICE BULLETIN

N U M B E R 27 - 53

Flying Controls: To introduce a re-designed fork end fitting on the Anti-Up Float Spring Pot in Elevator Control Circuit,

Modification No. 1080

1. Planning Information

A Effectivity

Skyvan Series 3

L Reason

Evidence of a premature fatigue has been reported.

C Description

The fork end fitting on the spring pot has been re-designed in steel.

D Compliance

Recommended.

E Approval

This modification and the technical contents of this Bulletin which affect air-worthiness have been approved under the authority of the Air Registration Board Design Approval No. AD/1023/45.

F Manpower

4 Man Hours.

G Material Cost and Availability

Modification Kit No., 27-53 is required to accomplish this modification. The price of the kit is $19,00 and may be obtained from:

Skyvan Co-Ordinator Product Support Department Short Brotlers & Harland Ltd Queen's Island BELFAST BT3 9DZ

This offer is available for three months after receipt of this Bulletin.

Original Issue Nov. 23/70

27-53-1080

Revision No.

No. of Pages 9

Page 1

SHORT BROTHERS & HARLAND LTD. ~ P.O. BOX 241 QUEEN'S ISLAND BELFAST 3 N. IRELAND Telegram: AIRCRAFT BELFAST Telephone: BELFAST 58444 Telex: 74688

SHORTS

SERVICE BULLETIN

NUMBER 27 - 53

Flying Controls: To introduce a re-designed fork end fitting on the Anti-up Float Spring Pot in Elevator Control Circuit.

Modification No. 1080

1. Planning Information (Cont'd.)

H Tooling

No special tooling is required for this modification.

1. Weight & Balance

Weight change +0.1 lb. Moment change +2 lb/ft.

J References

Illustrated Parts Catalogue Chap. 27-10 Plg.12

27-53-1080

Original Issuer Nov. 23/70

Page 2

Revelios No.

SHORT BROTHERS & HARLAND LTD. - P.O. BOX 241 QUEEN'S ISLAND BELFAST 3 H. IRELAND Teleorems: AIRCRAFT BELFAST Telephone: BELFAST 56444 Teletext: 74688

Attachment 7

SHORTS

SERVICE BULLETIN

NUMBER 25 - 56

Equipment & Furnishing: To fit guards at near of 1st and 2nd Pilot's Seats.

Modification No. 1086

1. Planning Information

A Effectivity

B Reason

C Description

D Compliance

E Approval

F Manpower

G Material Cost and Availability

Skyvan Series 3

To ensure that mechanical controls in pilo's seat pedestal are fully guarded.

Fit guard under seat frame SC7-16-160 at rear of seat and cover 2 flanged holes in seat back.

Recommended.

This mod has been approved by the Air Registration Board and the technical contents of this Bulletin affecting air-worthiness has been approved under the authority of the Air Registration Board Design Approval No. AD/1023/45.

5 Man Hours.

Mod Kit 25-56 is required to accomplish this mod. The price of the kit is £21,34 and is available for three months after receipt of this Bulletin. Orders for kits should be addressed to:

Skyvan Co-Ordinator

Product Support Department

Short Brothers & Harland Ltd

P.O. Box 241

Queen's Island

BE1.FAST BT3 9DZ

Original Issuei Nov. 23/70

25-56-1086

Revisive No.

No. of Pages 7

Page 1

SHORT BROTHERS & MARLAND LTD. - P.O. BOX 241 QUEEN'S ISLAND BELFAST 3 N. IRELAND

Telehome: AIRCRAFT BELFAST

Telephones BELFAST 58444

Tolent 74688

SHORTS

SERVICE BULLETIN

NUMBER 25 - 56

Equipment & Furnishing: To fit guards at rear of 1st and 2nd Pilot's Seats,

Modification No. 1086

1. Planning Information (Cont'd.)

H ToolING

No special tooling required.

1 Weight & Balance

Weight change + .5 lb. Moment change - 4 lb.ft.

J Reference

Illustrated Parts Catalogue Chapter 25, 10 Fig 2 and 3.

25-56-1086

Page 2

Original Issues Nov. 23/70

Revisition No.

SHORT BROTHERS & HARLAND LTD. - P.O. BOX 241 QUEEN'S ISLAND BELFAST 3 N. IRELAND Telephone: AIRCRAFT BELFAST Telephone: BELFAST 58444 Teletext: 74668

CARGO RESTRAINT

〔图〕.。。。\n

FIG. 18.3.

Sept.67

〔图〕000LBRESFRAtNTFITTING\n

VEHICLE RESTRAINT

〔图〕插图 〔图〕。\n 700

FIG. 18.4. Sept.67.

〔图〕4000 LBRESTRAINTFITTING\n SED H38A