# NTSB FTW96FA208: Jerrell RV-4, N44AZ, Englewood, CO, May 11, 1996 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: May 11, 1996, 11:34 local (17:34 UTC) - Place: Englewood, CO - Coordinates: 39.579765, -104.860015 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.5798&lon=-104.8600&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal, 1 uninjured - Status: Completed, report February 3, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 19638 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW96FA208 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/19638/pdf - Page: https://openairdocs.org/ntsb/FTW96FA208 ## Probable cause (aircraft 2) failure of the pilot of the RV-4, N44AZ, to comply with an ATC clearance by landing on the wrong runway, and the failure of the pilot of the SU-29, N55SU, to maintain an adequate visual lookout. Factors in the accident were: the failure of the air traffic controller to restate the landing runway to the pilot of the RV-4 during a critical period of flight, his failure to advise the pilot of the RV-4 that operations were being conducted on the adjacent runway, a high traffic workload which resulted from an airport open house, and a lack of coordination to accommodate the high traffic workload. ## Probable cause (aircraft 1) failure of the pilot of the RV-4, N44AZ, to comply with an ATC clearance by landing on the wrong runway, and the failure of the pilot of the SU-29, N55SU, to maintain an adequate visual lookout. Factors in the accident were: the failure of the air traffic controller to restate the landing runway to the pilot of the RV-4 during a critical period of flight, his failure to advise the pilot of the RV-4 that operations were being conducted on the adjacent runway, a high traffic workload which resulted from an airport open house, and a lack of coordination to accommodate the high traffic workload. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Midair collision, landing - flare/touchdown - atc clearance - not complied with, pilot in command (cause) - wrong runway - selected, pilot in command (cause) - control tower service - inadequate, atc personnel(lcl/gnd/clnc) (contributing factor) - excessive workload (task overload), atc personnel(lcl/gnd/clnc) (contributing factor) - crew/group coordination - inadequate, atc personnel(lcl/gnd/clnc) (contributing factor) - visual lookout - inadequate, pilot of other aircraft (cause) - Midair collision, landing - flare/touchdown - atc clearance - not complied with, pilot of other aircraft (cause) - wrong runway - selected, pilot of other aircraft (cause) - control tower service - inadequate, atc personnel(lcl/gnd/clnc) (contributing factor) - excessive workload (task overload), atc personnel(lcl/gnd/clnc) (contributing factor) - crew/group coordination - inadequate, atc personnel(lcl/gnd/clnc) (contributing factor) - visual lookout - inadequate, pilot in command (cause) ## Analysis (aircraft 2) The pilot of the RV-4, N44AZ, had made initial contact with the control tower on the west arrival frequency, and was instructed to report entering a right downwind for runway 17R, which he acknowledged. At about the same time, the pilot of the Sukhoi SU-29, N55SU, made initial contact with the control tower on the east arrival frequency and was instructed to report on a left base for runway 17L. Both pilots were subsequently cleared to land on their respective runways. Instead of landing on his assigned runway 17R, the pilot of the RV-4 landed on 17L. The SU-29 then landed on top of the RV-4. The FAA's ATC handbook advises controllers to restate the landing runway whenever there is a possibilty of a conflict with another aircraft which is using or planning to use another runway. The threshold of runway 17R is 1,800 feet beyond the threshold of runway 17L. The airport was hosting an open house at the time, and airborne flights from a 'Parade of Flight' were in progress. ## Analysis (aircraft 1) The pilot of the RV-4, N44AZ, had made initial contact with the control tower on the west arrival frequency, and was instructed to report entering a right downwind for runway 17R, which he acknowledged. At about the same time, the pilot of the Sukhoi SU-29, N55SU, made initial contact with the control tower on the east arrival frequency and was instructed to report on a left base for runway 17L. Both pilots were subsequently cleared to land on their respective runways. Instead of landing on his assigned runway 17R, the pilot of the RV-4 landed on 17L. The SU-29 then landed on top of the RV-4. The FAA's ATC handbook advises controllers to restate the landing runway whenever there is a possibilty of a conflict with another aircraft which is using or planning to use another runway. The threshold of runway 17R is 1,800 feet beyond the threshold of runway 17L. The airport was hosting an open house at the time, and airborne flights from a 'Parade of Flight' were in progress. ## Factual narrative (aircraft 2) See Narrative for FTW 96-F-A208A. ## Factual narrative (aircraft 1) HISTORY OF FLIGHT On May 11, 1996, at 1134 mountain daylight time, a Jerrell RV-4, N44AZ, registered to the pilot, collided in midair with a Sukhoi Su-29, N55SU, registered to its pilot, while landing at Englewood, Colorado. Visual meteorological conditions prevailed at the time, and no flight plans were filed. N44AZ was destroyed, and N55SU sustained minor damage. The private pilot in N44AZ was fatally injured, and the airline transport pilot in the N55SU was not injured. Both personal flights were being conducted under Title 14 CFR Part 91. The flight of N44AZ originated at Peyton, Colorado, approximately 1100. The flight of the N55SU originated at Watkins, Colorado, approximately 1115. The pilot of N44AZ obtained a weather briefing via telephone from the Denver Automated Flight Service Station (AFSS), and was advised that VFR flight was not recommended due to localized fog in the Colorado Springs area. At the time, Centennial Airport was hosting an open house. It featured static displays of aircraft and a fly-by, called the "Parade of Flight." According to Centennial Control Tower tape recordings and transcripts, the pilot of N44AZ contacted the west controller at 1127:50 and advised he was "en route your airport...directly south of the airport, south of the power lines." He was instructed to report entering a right downwind leg for runway 17R. The pilot acknowledged. Shortly thereafter, at 1128:20, the pilot of 55SU contacted the east controller and advised he was "Aurora Reservoir, landing." The controller told him to "plan a left base entry abeam Cherry Creek, (runway) one seven left." The pilot acknowledged. At 1130:41, the pilot of N55SU advised he was "over the Aurora Reservoir, just west of the reservoir now." He was told he would be "following a flight of four, the lead is a DC-3. The wingman are T-6s. That's who you're following, there. High to your left, turning left base." The pilot reported he had the traffic in sight. At 1131:03, the pilot of N44AZ reported he was "entering downwind runway one seven right." The pilot of N55SU was cleared to land on runway 17L at 1132:10 and again at 1133:55. Both times he acknowledged the clearances and repeated the landing runway to which he had been assigned. At 1132:16, the pilot of N44AZ was told he was "number three, follow a twin Cessna on right base north of Arapahoe Road. Runway one seven right, cleared to land. Report traffic in sight." The pilot replied, "I understand. I do not have the traffic in sight. I'll proceed north to Arapahoe (Road)." The pilot of the twin Cessna turned onto final approach and inadvertently aligned himself with runway 17L. The controller called the pilot at 1132:56 and asked him to "verify lined up for runway one seven right. You appear to be lined up for the left." The pilot replied, "I requested left. I thought you gave it to me..." The controller then reiterated the clearance to land on runway 17R. At 1133:30, the controller advised the pilot of N44AZ, "...your traffic's over the numbers. The pilot replied, "I got him, I see him now." Seconds later, the SU-29 landed on top of the RV-4. The collision occurred approximately 800 feet past the threshold of runway 17L. The Su-29 is a 2-place, tandem seat airplane and the pilot flies solo from the rear seat. The pilot told investigators that because he was in the rear seat and forward visibility is restricted, he was forced to do "periodic slight S-turns to check for traffic...the runway (17L) was clear, I continued the approach until contact was made with an aircraft on the approach end on runway 17L. I landed and rolled to a stop in the center of 17L." The pilot said that his approach speed was 180 km (112 mph). PERSONNEL INFORMATION According to N44AZ pilot's logbook, he had flown into Centennial Airport on at least nine different occasions. The pilot of N55SU, a Boeing 737 captain for a major U.S. airline, said he routinely flew into Centennial Airport and was familiar with the airport layout and air traffic control procedures. AERODROME INFORMATION Centennial Airport's (APA) runway 17L is 10,001 feet long and 100 feet wide. It is asphalt paved, grooved, and the main precision instrument runway. Runway 17R is 7,003 feet long and 77 feet wide. It is also asphalt paved with a porous friction coarse overlay. There are no instrument approaches to this runway, and it is used for VFR operations only. According to control tower supervisor, the threshold of runway 17R is 1800 ft beyond the threshold of runway 17L. The two runways are 700 ft apart. WRECKAGE AND IMPACT INFORMATION The collision between N44AZ and N55SU occurred approximately 800 feet from the threshold of runway 17L. The pilot of N55SU said he felt a mild bump and he eased back the control stick. The airplane rose slightly, then settled back to the runway. As the airplane rolled out, the pilot noticed there were "stubs where the propeller blades use to be." He stopped the airplane alongside the runway, secured the engine, and got out to assess the airplane damage. When he looked back and saw the wreckage of N44AZ in the middle of the runway, he realized he had been involved in a midair collision. After being struck, N44AZ rolled approximately 200 feet before coming to a halt. Several witnesses said N44AZ was on the runway when the collision occurred. Others said it was still airborne over the runway. When the NTSB investigator arrived on the scene, N44AZ was still on runway 17L. Cockpit controls (fuel selector, mixture, magnetos) had been secured by CFR (crash/fire/rescue) personnel. Examination disclosed the right elevator trailing edge and the top of the vertical stabilizer had slash marks similar to propeller strikes. The dorsal fin forward of the vertical stabilizer had been torn off. The canopy was shattered. Slightly aft of the canopy was another slash mark. There were black rubber smears on the tops of both wings, and the wings were compressed downward. The left wing fuel tank had been compromised. The main landing gear was pushed down and out. The intact 2-blade wooden propeller remained attached to the crankshaft. The back surfaces of the propeller were painted black, and there were scratch marks on these surfaces. Prior to the arrival of NTSB, FAA officials had given airport personnel permission to tow N55SU to a nearby hangar. Examination disclosed all three composite propeller blades were shattered. A potion of the propeller spinner was missing. There were black paint transfer marks on the dented lower left engine cowling. MEDICAL AND PATHOLOGICAL INFORMATION Dr. Michael J. Dobersen of the Arapahoe County Coroner's Office performed an autopsy (#96-76) on the pilot of N44AZ. A toxicological screen was performed by FAA's Civil Aeromedical Institute. No cyanide, ethanol, or drugs were detected. A carbon monoxide test was not possible. TESTS AND RESEARCH An Air Traffic Control specialist from NTSB's Operational Factors Division was dispatched to assist in the investigation. According to his report, 6 controllers --- were on duty in the control tower at the time of the accident: two local controllers, two spotters, a ground controller, and an area supervisor. All of the controllers were interviewed. Local Controller 2, who was handling west operations, stated he first observed N44AZ when it was on downwind, almost abeam the tower, at an altitude between 6,500 and 6,600 feet msl. He advised the pilot his landing sequence, assigned runway, and traffic he was following. He next saw the airplane on base leg for runway 17R, and he reiterated the traffic advisory. His attention was diverted to new traffic depicted on the BRITE radar, an airplane that was turning off the runway, and another airplane that was blocking an intersection. When he looked up, he saw the collision. The controller said he felt the briefing he re ## Aircraft 1 - Registration: [N44AZ](https://openairdocs.org/deregistered/N44AZ-1996-07-24), registration cancelled 1996-07-24, S/N 1 (OpenAirDocs) - Reported make and model: JERRELL RV-4 - Registry model: [Jerrell Donald A JERRELL RV-4](https://openairdocs.org/model/jerrell-donald-a-jerrell-rv-4) (registry code 05608LB) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 1 - Airframe hours: 223 - Engines: Lycoming O-320-E3D 150 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Registered owner: James L. Lenahan - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, April 29, 1996, 1 hours before - Departed: 00V, PEYTON, CO - Destination: APA - Airport: APA, Centennial, runway 17L, 10,001 × 100 ft, asphalt ## Aircraft 2 - Registration: [N55SU](https://openairdocs.org/deregistered/N55SU-2014-10-09), registration cancelled 2014-10-09, S/N 73-05 (OpenAirDocs) - Reported make and model: Sukhoi SU-29 - Registry model: [Sukhoi SU-29](https://openairdocs.org/model/sukhoi-su-29) (registry code 9850103) (OpenAirDocs) - Category: Airplane - Serial number: 73-05 - Airframe hours: 123 - Engines: Vendeneyev M-14P 360 horsepower reciprocating - Damage: Minor damage - Flight: Personal, Part 91 - Registered owner: Donald W. Nelson - Airworthiness certificate: Standard, Aerobatic - Last inspection: 100 hour, February 8, 1996, 29 hours before - Departed: FTG, WATKINS, CO - Destination: APA - Airport: APA, Centennial, runway 17L, 10,001 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N44AZ; age 61; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: front; toxicology performed; flight hours: 736 total, 171 in this make and model, 663 as pilot in command, 1 in the last 24 hours - Pilot, aircraft N55SU; age 55; flight instructor, flight engineer, commercial, airline transport; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: rear; flight hours: 21,000 total, 35 in this make and model, 25 in the last 90 days, 8 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 4 knots - Visibility: 40 statute miles - Lowest ceiling: none - Temperature: 66 °F, dew point 30 °F - Altimeter: 30.00 inHg - Observed at: APA ## FAA reports on this event (2) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19960511010161A](https://openairdocs.org/incident/19960511010161A), May 11, 1996: Amtr RV4, Englewood, CO, Substantial damage, 1 fatal. Landed on wrong runway, hit by aircraft cleared to land on this runway. - [Accident 19960511046492A](https://openairdocs.org/incident/19960511046492A), May 11, 1996: Sukhoi SU29, Denver, CO, Minor damage. (.4) The pilot of the RV-4, N44AZ, had made initial contact with the control tower on the west arrival frequency, and was instructed to report entering a right… ## Other investigations on N44AZ (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB SEA91LA154](https://openairdocs.org/ntsb/SEA91LA154), Jul 4, 1991: Jerrell RV-4 (N44AZ), Yellowstonepark, WY, substantial damage, 1 fatal. Probable cause: A COLLAPSED INDUCTION AIR DUCT. FACTORS INCLUDE INADEQUATE DESIGN BY THE MANUFACTURER/BUILDER, AND A MISJUDGED RATE OF DESCENT BY THE PILOT. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.