E PLURIBUS UNUM

NATIONAL TRA SPORTATIO

N

B OARD

SAFE T Y

N

National Transportation Safety Board 

Washington, D.C. 20594 

Aviation Accident Brief

Accident Number: NYC05MA039 

Operator: LifeNet, Inc. 

Aircraft and Registration: Eurocopter EC-135 P2, N136LN 

Location: Oxon Hill, Maryland 

Date: January 10, 2005 

Adopted On: December 4, 2007 

HISTORY OF THE FLIGHT 

On January 10, 2005, about 2311 eastern standard time,1

 a Eurocopter Deutschland 

GmbH EC-135 P2 helicopter, N136LN, operated by LifeNet, Inc., as Life Evac 2, crashed into 

the Potomac River during low-altitude cruise flight near Oxon Hill, Maryland. The certificated 

commercial pilot and the flight paramedic were killed, and the flight nurse received serious 

injuries. The helicopter was destroyed. The positioning flight was conducted under the 

provisions of 14 Code of Federal Regulations (CFR) Part 91 and visual flight rules (VFR) with a 

company flight plan filed. Night visual meteorological conditions prevailed at the time of the 

accident. 

The flight originated at the Washington Hospital Center Helipad (DC08), Washington, 

D.C., about 2304, and was en route to Stafford Regional Airport (RMN), Stafford, Virginia. 

Global positioning system (GPS) data for the flight2 showed that the helicopter proceeded 

toward the Federal Aviation Administration’s (FAA) published helicopter route 1.3

 According to 

FAA air traffic control (ATC) transcripts, the pilot contacted the local controller at Ronald 

Reagan Washington National Airport (DCA), Washington, D.C., at 2305:47 and stated, 

“washington tower life evac two . . . sir we’re at uh medstar like to go out to uh r f k route one 

 1

 Unless otherwise indicated, all times are eastern standard time, based on a 24-hour clock. 

2

 The helicopter was equipped with an Outerlink GPS tracking system, which enabled communications 

specialists at LifeCom in Omaha, Nebraska, to track the location of each flight and provide flight requests and 

flight-following services to the pilots. The GPS data recorded by the operator included ground track and altitude 

information and were consistent with the ATC radar data for the accident flight. 

3

 The FAA’s National Aeronautical Charting Office (NACO) publishes helicopter route charts that depict 

aeronautical information for helicopter pilots, including helicopter route charts that depict routes, heliport locations, 

navigational aids, geographical features, landmarks, and obstructions. According to the NACO BaltimoreWashington Helicopter Route Chart current at the time of the accident, a section of helicopter route 1 followed the 

Anacostia River, passed near Robert F. Kennedy Memorial Stadium, and intersected with route 4 at the Potomac 

River. Helicopter route 4 ran north-south along the Potomac River and crossed the Woodrow Wilson Bridge. 

According to the chart, the route’s maximum altitude restriction north of the bridge was 200 feet and south of the 

bridge was 300 feet. 
2

then to route four south.” The local controller responded, “life evac two (unintelligible) bravo 

airspace altimeter three zero two five.” The pilot responded, “roger understand cleared as 

requested.” 

 then flew 

southbound along the Potomac River toward Woodrow Wilson Bridge (see figure 1). 

Figure 1. Helicopter route chart with routes 1, 4, and select landmarks highlighted. 

Examination of FAA ATC radar data showed that the helicopter intercepted a segment of 

published helicopter route 1, followed it southwest to intercept helicopter route 4, and

NTSB/AAB-07/04 
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As the helicopter flew over the river toward Woodrow Wilson Bridge, its Mode C 

transponder reported that its altitude varied from 0 to 100 feet.4

 When the helicopter was about 

0.5 nautical mile (nm) north of the bridge, its reported Mode C altitude was 200 feet. 

At 2311:20, the pilot reported to the local controller, “life evac two is at the Woodrow 

Wilson [Bridge],” and the controller responded, “life evac two washington tower traffic on a 

ten mile final is a seven [sic] an airbus.”5

 At 2311:30, the pilot responded, “roger we have him in 

sight and will be out of his way,” and the controller stated, “life evac two maintain visual 

separation from traffic.” ATC radar data showed that, at the time of the pilot’s response, the 

helicopter was about 0.25 nm north of the Woodrow Wilson Bridge at an altitude of about 

200 feet. The pilot made no further radio communications. 

According to the flight nurse, who was seated in the helicopter’s left front copilot’s seat, 

the pilot maneuvered the helicopter to cross the bridge midspan. The flight nurse stated that the 

helicopter appeared to be at the same or higher altitude than the lights he saw on some 

construction cranes near the Woodrow Wilson Bridge. He stated that he “called the lights” on 

both sides of the river to the pilot and that the pilot acknowledged him. According to a Maryland 

Department of State Police report, the flight nurse also stated that there was a “commercial 

airplane coming into [DCA], and the pilot . . . made a change in his flightpath and started to 

descend.”6

 

According to ATC radar data, at 2311:39, the helicopter had crossed over the Woodrow 

Wilson Bridge and was just south of the bridge with a ground track of about 180o and an altitude 

of about 200 feet. Four seconds later, the helicopter had a ground track of about 190o and an 

altitude of about 100 feet. The helicopter’s last recorded position at 2311:48 showed a ground 

track of about 200o and an altitude of about 0 feet. According to ATC radar data, at the time of 

the helicopter’s last radar return, the northbound Airbus that the local controller previously 

mentioned was about 2.2 nm south of the helicopter’s position at an altitude of about 1,700 feet. 

According to the flight nurse, after the helicopter flew over the southern half of the 

Woodrow Wilson Bridge, the next thing he recalled was being submerged in water with his 

seatbelt on and his helmet off. He stated that the helicopter’s master caution lights and panel 

segment lights did not illuminate and that he did not hear any audio alarms sound before the 

 4

 A Mode C transponder transmits the helicopter’s identification and altitude information in response to 

interrogation signals received from ground-based radar equipment. Mode C information, if available, provides the 

helicopter’s altitude above mean sea level (msl) in 100-foot increments. All altitudes in this report were derived 

from transmitted Mode C altitudes. The elevation of the river in the vicinity of the accident site is about 10 feet 

above msl. 

5

 At the time that the controller notified the helicopter pilot of the Airbus, the Airbus was south of the 

helicopter’s position and was about to turn and fly northbound for the final approach to DCA. The controller also 

advised the Airbus flight crew to expect that, once they were on the final approach, the southbound helicopter would 

be at their 12 o’clock position and 2 miles away. A member of the Airbus crew stated to the controller that the 

helicopter was in sight. 

6

 According to the police report, this interview took place about 10 hours after the accident at the hospital where 

the flight nurse was receiving treatment. 

NTSB/AAB-07/04 
4

crash. He stated that the pilot did not execute any evasive maneuvers or communicate any 

difficulties, either verbally or nonverbally. 

According to witnesses in vehicles on the Woodrow Wilson Bridge, the helicopter 

crossed over the bridge before it descended and then impacted the water. None of the witnesses 

reported seeing the helicopter impact any objects before its descent. The wreckage was located in 

the Potomac River about 0.5 nm south of the Woodrow Wilson Bridge. 

At 2314:46 (about 3 minutes after the helicopter crashed), the DCA local controller 

stated, “life evac two frequency change approved.” The controller received no reply and made no 

further attempts to contact the flight. The Maryland State Police later notified the controller of 

the crash. 

PILOT INFORMATION 

The pilot, age 56, was hired by LifeNet in June 2004. He held a commercial pilot 

certificate with ratings for airplane single- and multi-engine land, rotorcraft helicopter, and 

instrument helicopter. His most recent FAA second-class airman medical certificate was issued 

on May 28, 2004. On his application for the medical certificate, he reported 1,500 hours total 

civilian flight experience, 30 hours of which were accumulated in the previous 6 months.7

 A 

review of company records showed that, in the 90 days, 30 days, and 24 hours before the 

accident, the pilot flew 42 hours, 12 hours, and 1 hour, respectively, and performed a total of 

71 night landings. 

According to LifeNet’s training records, during the pilot’s first few weeks of 

employment, the company provided 12 hours of basic indoctrination training, as well as 20 hours 

of initial ground training and 7.8 hours of flight training in the Messchersmitt Bolkal Blohm 

BK-117 helicopter. The training records indicated that the pilot completed the initial pilot-testing 

requirements of 14 CFR 135.293 and the pilot-in-command flight check required by 

14 CFR 135.299 on July 8, 2004, in the BK-117. The company subsequently provided the pilot 

18 hours of transition ground training and 5.8 hours of transition flight training for the EC-135, 

and the pilot completed the initial testing and flight-check requirements in the EC-135 on 

October 3, 2004. 

During his employment with LifeNet, the pilot accumulated 51.5 flight hours in the 

BK-117 and 40.8 flight hours in the EC-135. According to LifeNet’s assistant chief pilot, when 

the pilot applied for employment, he reported that he had been retired since 1997 but that he was 

current for Part 135 operations and had passed Part 135 flight checks in a Bell 206 helicopter in 

February 2004 and in a BK-117 in April 2004. The assistant chief pilot stated that, according to 

the pilot’s interview and résumé, he had been a military pilot in the U.S. Army from 1968 to 

1971 and had accumulated about 2,400 military flight hours in helicopters, including about 

350 hours of night flying and about 70 hours of instrument flying. From 1971 to his retirement in 

 7

 On the medical application, the pilot listed as his employer the name of a Part 135 helicopter operator that had 

terminated his employment 1 month earlier. 

NTSB/AAB-07/04 
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1997, the pilot worked for a corporation in both nonflying and flying positions. During his 

26-year corporate employment, the pilot accumulated 400 hours total flight experience in 

Agusta 109 and Sikorsky S76 helicopters and about 300 total civilian flight hours in fixed-wing 

airplanes. 

The résumé that the pilot submitted to LifeNet did not list his most recent employer, 

which was another Part 135 helicopter operator that had terminated his employment after about 

2 weeks. According to the chief pilot for that company, the accident pilot was hired on April 12, 

2004, but the company terminated his employment on April 28, 2004, because the pilot was 

unable to adequately perform complex tasks in the helicopter or fly a “complete mission” 

involving several tasks in a series.8 During his training with this operator, the pilot accumulated 

about 7 hours of flight time in a BK-117. 

Two medical crewmembers who flew with the pilot the night before the accident on the 

same route as the accident flight and on other previous flights stated that the pilot flew the 

helicopter in a manner equivalent to other pilots in the company. 

HELICOPTER INFORMATION 

The helicopter was manufactured in 2004 and was equipped with two Pratt & Whitney 

Canada PW206B-series turboshaft engines. The helicopter was configured with a front right pilot 

seat, a front left copilot’s seat, an aft-facing passenger seat in the left aft cabin, and an area for 

one medical patient in the aft cabin. Each seat was equipped with lap belt and shoulder harness 

restraints. 

The helicopter was maintained in accordance with an FAA-approved aircraft inspection 

program. According to maintenance records, the most recent 50-hour inspection was performed 

on December 17, 2004. The most recent 100-hour inspection was performed on 

November 23, 2004, at an airframe total time of 94.5 hours. At the time of the accident, the 

helicopter had accumulated 166.6 total hours. 

The maintenance logbook recovered from the helicopter included an entry dated 

January 10, 2005, for an inoperative radar altimeter.9

 The maintenance log also contained a 

“Record of Minimum Equipment List (MEL) Items and Deferred Maintenance” section that 

 8

 In accordance with the Pilot Records Improvement Act of 1996, which was enacted to ensure that an operator 

adequately investigates a pilot’s background before hiring him or her, LifeNet requested records from the previous 

employer listed on the pilot’s résumé. Because the pilot did not disclose to LifeNet his most recent employer, 

LifeNet was unaware of the employment termination. 

9

 A radar altimeter is also known as a radio altimeter. The radar altimeter in the accident helicopter, when 

functional, provided a digital readout of altitude in feet above terrain, a low/high warning (visual amber indicator), 

and an indicator on the pilot’s multifunction display. 

NTSB/AAB-07/04 
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included an entry stating that the inoperative radar altimeter could be deferred for maintenance 

until January 20, 2005.10 

METEOROLOGICAL INFORMATION 

According to the DCA automated surface observing system, located about 3.5 nm north 

of the accident site, the reported conditions at 2251 were winds calm, visibility 10 statute miles, 

broken clouds at 13,000 feet and 20,000 feet, temperature 45o Fahrenheit (F), dew point 36o F, 

and altimeter setting 30.25 inches of mercury. 

According to recorded astronomical data, at the time and location of the accident, a new 

moon was below the horizon and provided no illumination. 

WRECKAGE AND IMPACT INFORMATION 

The helicopter was recovered from about 5 feet of water in the Potomac River. Wreckage 

was scattered along a north-south oriented debris path. The wreckage was recovered, and 

examination indicated no evidence of a collision with a bird or other object, fatigue fractures, or 

other anomalies. 

The main fuselage section was separated into the lower cockpit area and upper cockpit 

area. The lower cockpit area included the flight-crew floorboard section, antitorque pedals, the 

forward skid frame, and fragments of the fuel tank. The upper cockpit area included the flightcontrol tubes, the center electrical and flight-control structure, the upper flight-control deck, 

engines, the main transmission, and the rotor head. 

The cyclic, collective, and antitorque control systems were damaged, and portions of 

some push-pull tubes were separated and not recovered. Continuity could not be established 

because of the separations; however, the separated surfaces showed fracture features consistent 

with impact-related overload. 

The main rotor mast was in place and intact in the main transmission. The root ends of 

the four main rotor blades remained attached to the main rotor hub on the mast. Three of the four 

pitch-change links were connected to their two attach points, and the other pitch-change link was 

fractured in the middle. The fracture surfaces were consistent with compression-bending 

overload. 

 10 According to the FAA, certain aircraft equipment may be inoperative without compromising an acceptable 

level of safety if the operator adheres to the conditions and limitations stated in the operator’s FAA-approved MEL. 

The FAA’s master MEL for the EC-135-series helicopter, on which the operator’s MEL is based, states that the 

helicopter may be dispatched with an inoperative radar altimeter, provided that the radar altimeter is repaired within 

10 calendar days, excluding the day that the malfunction was recorded in the aircraft maintenance records. 

According to LifeNet’s director of operations, when the radar altimeter was functional, generally, the pilots of twinengine helicopters would set the altitude preselect/alerter to the landing decision point (LDP) altitude. The LDP is 

the last point in the approach and landing path at which a balked landing can be accomplished with a failed or failing 

critical engine and with the engine failure recognized by the pilot. 

NTSB/AAB-07/04 
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Portions of all four main rotor-blade tips were recovered. Each main rotor blade had 

overload fractures and chordwise scoring on the lower blade skin between 6 to 12 inches from 

the blade hub. Each blade also showed fractures along the blade span, consistent with impact 

damage. The main transmission remained attached to the center section of the upper airframe 

structure, and all four mounting points were intact. The main transmission turned freely, no chips 

were found on the detectors, and the transmission appeared intact and functional. 

The tail boom was separated at the aft fuselage frame. The tail section included the 

complete fenestron assembly11 with the tail rotor gearbox and tail rotor. The tail rotor driveshaft 

was displaced forward about 1.5 inches. The aft portion of the driveshaft, which was carbon 

composite, was found fractured, torsionally cracked, and deformed. All tail rotor blades 

remained complete and attached to the hub. The fenestron shroud around the tail rotor showed a 

rotational scrape at the 5 o’clock position. The width of the scrape corresponded with the tail 

rotor-blade width. 

Both engines showed little damage, and the gas generator (N1 compressor and turbine) 

and power turbine (N2 turbine) for each engine rotated freely. Nonvolatile memory data 

extracted from the electronic engine control units for each engine revealed no evidence of 

preimpact faults. 

MEDICAL AND PATHOLOGICAL INFORMATION 

The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, 

performed toxicological testing on specimens from the pilot, and no drugs or alcohol were 

detected in the pilot’s blood or urine. 

SURVIVAL ASPECTS 

The State of Maryland, Office of the Chief Medical Examiner, performed autopsies on 

the pilot and the flight paramedic. The medical examiner determined that the pilot’s cause of 

death was “multiple injuries.” The flight paramedic’s cause of death was listed as “drowning 

complicated by hypothermia”;12 the paramedic was found still belted into the left aft cabin seat. 

According to the flight nurse, after the crash, he was submerged in water but was able to 

remove his seat restraints, exit the helicopter, and remain near the helicopter’s partially 

submerged tail section until a rescue boat arrived. He was taken to a hospital and treated for a 

broken arm and burns. 

Several of the witnesses who saw the helicopter impact the water telephoned 911 to 

report the crash. According to the DCA tower’s daily record of operation, the DCA controller 

 11 A fenestron is a type of helicopter tail rotor system in which the tail rotor assembly consists of a series of 

rotating blades shrouded within the vertical tail structure. 

12 The report also stated that the flight paramedic sustained a pelvic injury that, “although not fatal, may have 

contributed to death by restricting . . . mobility.” 

NTSB/AAB-07/04 
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received a call about 2326 from a Maryland State Police helicopter crew advising that they were 

inbound to investigate reports of a downed aircraft near the Woodrow Wilson Bridge. According 

to an incident report from the City of Alexandria (Virginia) Fire Department, Station 201, the 

station was notified about the downed aircraft at 2330:18 and dispatched the first of nine 

emergency medical service apparatuses about 2331:12; the first boat was dispatched at 2333:09. 

ORGANIZATIONAL AND MANAGEMENT INFORMATION 

LifeNet’s Part 135 certificate was issued in 1995. LifeNet is headquartered in 

Chesterfield, Missouri, and has 89 aircraft based at various locations across the country. 

LifeNet’s fleet includes various AS-350, BK-117, and EC-135 series helicopters, various models 

of Bell helicopters, Eurocopter BO-105 helicopters, McDonnell Douglas MDHS-MD-900 

helicopters, and Beech BE-100 and BE-200 twin-engine turboprop airplanes. LifeNet employs 

pilots and medical personnel. 

TESTS AND RESEARCH 

A National Transportation Safety Board performance engineer completed a performance 

study using the last 30 seconds of the flight’s Mode C radar data and the location of the crash site 

to estimate the helicopter’s bank angle and flightpath descent angle at impact, as well as the time 

of the crash. The study estimated that the helicopter’s flightpath angle was about -3o, its bank 

angle was about 12o right, and it impacted the water about 3.5 seconds after the last radar 

return.13 

The study also used primary and Mode C radar data to examine the helicopter’s 

proximity to other aircraft and to evaluate any possible encounter with wake turbulence or a bird 

flock.14 Review of the Mode C radar data showed that a 70-passenger Canadair Regional Jet 700 

(CRJ-700) passed northbound over Woodrow Wilson Bridge about 1 minute 45 seconds before 

the helicopter passed over the bridge. According to the data, the helicopter passed 900 feet 

directly beneath the flightpath of the CRJ-700. On the basis of the radar data, weather 

information, and information obtained through consultation with an FAA wake turbulence 

specialist, the study concluded that the time frame was sufficient to expect that the jet’s wake 

would be completely decayed before it could reach the helicopter and that, even if the wake had 

not decayed at all, its descent rate would not have been sufficient for it to have reached the 

helicopter. 

Review of the primary radar data showed that an area of primary returns, which could 

possibly represent a bird flock, occurred north of the bridge about 1 nm north of the point where 

the helicopter began its descent and about 30 seconds before the beginning of descent. The data 

showed that the helicopter’s flightpath continued undisturbed beyond the location of the primary 

 13 The study assumed that the helicopter followed a constant descent rate and angle from the location of the last 

radar return to the location of the wreckage and considered a Mode C uncertainty range of +/- 50 feet. 

14 The flight nurse reported that he observed a white bird fly up from the lower left of the helicopter before the 

accident. Two medical crewmembers who had flown with the accident pilot on the night before the accident 

reported observing a large flock of white birds flying up from the water near the Woodrow Wilson Bridge. 

NTSB/AAB-07/04 
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returns, which is not consistent with a sudden or catastrophic collision with a bird flock. No 

evidence of bird remains was observed in the area surrounding the accident site. 

Construction Crane Information 

During interviews, the flight nurse stated that, although he did not remember the 

helicopter striking anything, he thought that it must have struck an unlighted construction crane. 

Safety Board investigators used the recorded ATC radar data and data from the operator’s GPS 

to examine sites along the Potomac River. The helicopter’s projected ground track along the data 

points toward the accident site was at least 300 feet laterally from the nearest construction crane, 

and no additional obstacles were observed along the track. Examination of the five construction 

cranes closest to the flightpath showed no evidence of an aircraft strike or structural damage, and 

all of the cranes had the required lighting on top of their respective boom. Also, a Maryland 

Department of Transportation traffic surveillance camera located on the east side of the Potomac 

River at Woodrow Wilson Bridge captured video that showed, at the time of the accident, an 

aircraft overflew the bridge, passing above and beyond the construction cranes, then began to 

descend. 

Comparison of Accident Flight with Previous Flight on the Same Route 

The pilot had flown the route from DC08 to RMN the night before the accident. A review 

of the operator’s GPS data revealed that the previous flight’s ground track and altitudes were 

nearly identical to those of the accident flight while north of Woodrow Wilson Bridge and up to 

the point of crossing the bridge midspan at an altitude of about 200 feet. According to the data, 

after the helicopter crossed the bridge on the previous night’s flight, it continued southbound on 

a steady ground-track heading and at an altitude of about 200 feet until it was at least 3 nm south 

of the bridge, then it climbed. The data showed that the accident flight also crossed the bridge 

midspan at an altitude of about 200 feet; however, its heading then deviated to the right while it 

descended into the water. 

ADDITIONAL INFORMATION 

Night Flying and Featureless Terrain Considerations 

Several professional helicopter pilots who routinely fly along the Potomac River in the 

vicinity of the Woodrow Wilson Bridge were interviewed regarding their observations of 

physical lighting and the natural horizon of the shoreline. All of the pilots reported that the river 

widens south of the bridge and that the area becomes “very dark” because the parks and natural 

bird habitats there limit the physical lighting on the shoreline. 

One helicopter pilot reported the following in a written statement: 

Flying at night from North to South over the Woodrow Wilson Bridge is very 

similar to going into actual instrument conditions. A pilot [flying] low-level North 

of the bridge is typically flying VFR due to the intense amount of ground lights 

NTSB/AAB-07/04 
10

available along the river. Once the pilot crosses the bridge he is now flying into a 

black void. At this point an instrument scan must be established to maintain 

altitude. Because of the close proximity to water . . . a radar altimeter is necessary 

to ensure altitude awareness. 

According to the FAA Aeronautical Information Manual (AIM),15 chapter 8-1-5, 

Illusions in Flight, Featureless Terrain Illusion, “An absence of ground features, as when landing 

over water, darkened areas, and terrain made featureless by snow, can create the illusion that the 

aircraft is at a higher altitude than it actually is.” 

The FAA Airplane Flying Handbook,16 chapter 10, states the following about night 

flying: 

Night flying requires that pilots be aware of, and operate within, their abilities and 

limitations. . . . Night flying is very different from day flying and demands more 

attention of the pilot. The most noticeable difference is the limited availability of 

outside visual references. Therefore, flight instruments should be used to a greater 

degree. 

Air Defense Identification Zone and Flight Restricted Zone Communication Requirements 

After September 11, 2001, an Air Defense Identification Zone (ADIZ) was established 

for the Washington, D.C., area, which includes the DCA class B airspace. According to the 

National Security Flight Advisory, pilots are required to maintain two-way radio 

communications with a controller while in the ADIZ. The Washington, D.C., Metropolitan Area 

Flight Restricted Zone (FRZ), which includes an area within the ADIZ transitioned by the 

accident flight, also requires the pilot to maintain two-way radio communications with a 

controller. 

Pilots of flights that enter the ADIZ/FRZ typically maintain two-way radio 

communications with a controller and do not change from the assigned radio frequency until 

instructed to do so by a controller.17 Pilots who violate the provisions of the ADIZ/FRZ could be 

subject to criminal charges and/or FAA administrative action, including civil penalties and 

suspension or revocation of airman certificates, or military interception. 

 15 U.S. Department of Transportation, Federal Aviation Administration, Aeronautical Information Manual: 

Official Guide to Basic Flight Information and ATC Procedures (Washington, DC: FAA, 2006). 

16 U.S. Department of Transportation, Federal Aviation Administration, Airplane Flying Handbook, 

FAA-H-8083-3A (Washington, DC: FAA, 2004). 

17 The rules for operating within an ADIZ are outlined in 14 CFR Part 99 and include requirements for a 

functioning two-way radio and transponder, as well as certain procedural, position-reporting, and flight-planning 

requirements. The rules for operating within class B airspace are outlined in 14 CFR 91.131 and include two-way 

radio and transponder requirements. 

NTSB/AAB-07/04 
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ANALYSIS 

Examination of the helicopter revealed no mechanical deficiencies, and no evidence of 

impact with a bird or other object was found. Studies determined that an encounter with wake 

turbulence was unlikely. 

Other pilots who were familiar with the accident flight route reported that, because of the 

lack of physical lighting on the shoreline, flying south of the Woodrow Wilson Bridge at night 

was like flying into actual instrument meteorological conditions. According to the AIM and the 

FAA Airplane Flying Handbook, such an absence of ground features, especially at night, can 

result in illusions that make it difficult for a pilot to visually determine altitude, depth perception, 

and orientation. 

The helicopter crossed over the Woodrow Wilson Bridge at an altitude of about 200 feet, 

then it entered a gradual descent and right bank, and, about 14 seconds later,18 it impacted the 

water. Performance calculations estimated that the helicopter struck the water at a 3o nose-low 

and 12o right-bank attitude, which was consistent with the damage observed on the wreckage. 

Because the helicopter was traveling in dark conditions over featureless terrain, the pilot 

would have needed to reference the flight instruments to help maintain the helicopter’s safe 

altitude over the water. However, about 8 seconds before the onset of the helicopter’s banking 

descent, the pilot diverted his attention from the instruments, at least momentarily, because he 

stated to the controller that he was looking for the approaching Airbus traffic. Additionally, the 

flight nurse stated that, because of the traffic, the pilot “made a change in his flightpath and 

started to descend.” 

If the pilot had continued to look out the windscreen for the traffic, he would have had 

few or no outside visual ground references to provide information about the helicopter’s altitude, 

and detection of an unintentional descent during this time would have been difficult using 

external cues. Once the pilot detected any unintentional descent, he would have had to respond 

immediately to arrest it because of the helicopter’s cruise speed and low altitude. Other pilots 

familiar with the area stated that radar altimeters are necessary to ensure altitude awareness. 

During low-altitude flight, a functioning radar altimeter provides a pilot constant altitude 

information in feet above terrain and has an alerter function that can visually and/or aurally alert 

a pilot that the aircraft had descended below a preset altitude.19 However, on the night of the 

accident, the helicopter’s radar altimeter was inoperative. 

The night before the accident, the helicopter’s radar altimeter was functional, and the 

pilot successfully flew a nearly identical route southbound over the river, crossed the Woodrow 

 18 This includes the 10-second descent observed using radar data and the 3.5 seconds that the performance 

study estimated the helicopter continued to fly after the last radar return. 

19 The pilot can set the alerter function by setting the altitude bug, or indicator, at any altitude, in feet above 

terrain, that the pilot determines is appropriate for the flight or flight segment. The alerter will then produce a visual 

and/or aural warning (depending on the altimeter model) any time the aircraft descends below that height above 

terrain. 

NTSB/AAB-07/04 
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Wilson Bridge at an altitude of about 200 feet, and then continued southbound over the river and 

eventually climbed to a higher altitude. For the accident flight, the inoperative radar altimeter 

was allowable for 10 calendar days, according to conditions and limitations stated in the 

operator’s FAA-approved MEL. If a functioning radar altimeter had been available to and used 

by the pilot, it could have provided a constant altitude cue, in the form of a digital readout of feet 

above the terrain, to enhance his awareness of the helicopter’s height above the water. This cue 

may have prevented the pilot from descending the helicopter into the water. Additionally, the 

visual alerter features of the radar altimeter could have provided the pilot additional tools to alert 

him that the helicopter had descended below a set altitude.20

About 3 minutes after the helicopter crashed, the DCA local controller issued frequencychange instructions to the pilot but received no reply and was unaware that the helicopter had 

crashed. Because of the rules associated with the airspace, it would be unusual for a pilot not to 

maintain radio contact with the controller; thus, the controller should have attempted to locate 

the flight when he did not receive a reply.21 However, because witnesses immediately called 911 

to report the crash and rescue resources were dispatched, no evidence shows that the controller’s 

actions adversely impacted the timeliness of the rescue response. 

PROBABLE CAUSE 

The National Transportation Safety Board determines that the probable cause of this 

accident was the pilot’s failure to identify and arrest the helicopter’s descent, which resulted in 

controlled flight into terrain. Contributing to the accident were the dark night conditions, limited 

outside visual references, and the lack of an operable radar altimeter in the helicopter. 

 20 As a result of the investigations of this and another HEMS accident, the Safety Board issued Safety 

Recommendations A-07-111 through -112 relating to radar altimeters in HEMS operations. The recommendation 

letter is available on the Board’s Web site at <http://www.ntsb.gov/recs/letters/2007/A07_111_112.pdf>. 

21 The flight was operated under VFR; therefore, a controller would not typically continuously monitor its radar 

data. However, after the controller received no radio response from the pilot, he should have made further attempts 

to contact the flight by radio and should have noticed that radar data for the flight ceased. 

NTSB/AAB-07/04 
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BY THE NATIONAL TRANSPORTATION SAFETY BOARD 

MARK V. ROSENKER ROBERT L. SUMWALT 

Chairman Vice Chairman 

DEBORAH A. P. HERSMAN KATHRYN O. HIGGINS 

Member Member 

STEVEN R. CHEALANDER 

Member 

Adopted: December 4, 2007 

Member Higgins filed the following concurring statement on November 21, 2007, and 

was joined by Vice Chairman Sumwalt. 

NTSB/AAB-07/04 
14

NTSB/AAB-07/04 
15

NTSB/AAB-07/04 
16

NTSB/AAB-07/04