ERA13LA022

NTSB accident investigation · Hughes/Helicopter Assocs 369A · West Chester, PA · October 13, 2012

Accident · No injuriesLimited investigationFinal report
Date
October 13, 2012, 09:20 local (13:20 UTC)
Place
West Chester, PA
Injuries
5 uninjured
Phase of flight
Maneuvering
Aircraft
N546Hughes/Helicopter Assocs 369AN369SNHughes 369A
Defining events
Maneuvering-hover: Midair collisionManeuvering-hover: Midair collision
Weather
Visual (VMC) · Day
Status
Completed · report March 14, 2016
Report
Approved by Office Director
NTSB office
Eastern Region Aviation
Parties
FAA/FSDO
Case key
85324

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

The pilot’s failure to see and avoid the preceding helicopter while maneuvering for landing. Contributing to the accident were the flight lead pilot’s inadequate preflight briefing and in-flight instruction to the formation pilots, which resulted in the loss of the formation flight's integrity and the pilots’ situational awareness within the flight.

The other pilot’s failure to see and avoid the preceding helicopter while maneuvering for landing. Contributing to the accident were the flight lead pilot’s inadequate preflight briefing and in-flight instruction to the formation pilots, which resulted in the loss of the formation flight's integrity and the pilots’ situational awareness within the flight.

Findings · 4

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

N546 · Hughes/Helicopter Assocs 369A

N369SN · Hughes 369A

Attention/monitoring: monitoring other aircraftPersonnel issues › Psychological · Pilot of other aircraftHughes OH-6A: 1 caseAll aircraft: 231 casesProbable cause
Planning/preparation: flight planning/navigationPersonnel issues › Task performance · Not specifiedHughes OH-6A: 1 caseAll aircraft: 179 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

N546 · Hughes/Helicopter Assocs 369A

N369SN · Hughes 369A

Analysis

The formation flight of helicopters, designated Chalk 1 through 5, was en route to an annual airshow. The lead helicopter (Chalk 1) was on the left base leg of the traffic pattern at the nontower-controlled destination airport when the Chalk 3 helicopter pilot identified and announced that an airplane was on final approach for the landing runway. The Chalk 1 helicopter pilot announced that he was conducting a go-around and turned the helicopter left, inside the landing runway, and proceeded upwind. About the same time, the flight lead pilot, who was traveling in the trail position (Chalk 5), instructed the other helicopter pilots to "break left or land." The flight lead pilot's ambiguous instruction resulted in the breakdown of the formation flight's integrity. Instead of a flight of five helicopters and one airplane attempting to avoid conflict in the traffic pattern, each of the six individual aircraft were immediately placed in a position in which the pilots had to avoid potential collisions with the other aircraft. The Chalk 4 pilot subsequently lost sight of the Chalk 3 helicopter as the pilots of both helicopters were maneuvering for landing. The Chalk 4 helicopter pilot then landed the helicopter and was hover-taxiing to park when the helicopter collided with the Chalk 3 helicopter as its pilot was maneuvering it to land on the runway. Before the flight, the flight lead pilot presented briefing slides to the group of pilots; however, the slides did not provide any procedures for a loss of visual contact while flying in formation.

The formation flight of helicopters, designated Chalk 1 through 5, was en route to an annual airshow. The lead helicopter (Chalk 1) was on the left base leg of the traffic pattern at the nontower-controlled destination airport when the Chalk 3 helicopter pilot identified and announced that an airplane was on final approach for the landing runway. The Chalk 1 helicopter pilot announced that he was conducting a go-around and turned the helicopter left, inside the landing runway, and proceeded upwind. About the same time, the flight lead pilot, who was traveling in the trail position (Chalk 5), instructed the other helicopter pilots to "break left or land." The flight lead pilot's ambiguous instruction resulted in the breakdown of the formation flight's integrity. Instead of a flight of five helicopters and one airplane attempting to avoid conflict in the traffic pattern, each of the six individual aircraft were immediately placed in a position in which the pilots had to avoid potential collisions with the other aircraft. The Chalk 4 pilot subsequently lost sight of the Chalk 3 helicopter as the pilots of both helicopters were maneuvering for landing. The Chalk 4 helicopter pilot then landed the helicopter and was hover-taxiing to park when the helicopter collided with the Chalk 3 helicopter as its pilot was maneuvering it to land on the runway. Before the flight, the flight lead pilot presented briefing slides to the group of pilots; however, the slides did not provide any procedures for a loss of visual contact while flying in formation.

Factual narrative

On October 13, 2012, about 0920 eastern daylight time, two helicopters in a flight of five, a Hughes 369A, N369SN (Chalk 3), and another Hughes 369A, N546 (Chalk 4), collided during hover-taxi while landing at Brandywine Airport (OQN), West Chester, Pennsylvania. The 3 occupants in Chalk 3 and the 2 occupants in Chalk 4 were not injured. Chalk 4 sustained substantial damage to all four main rotor blades and the tail pylon. Chalk 3 sustained substantial damage to the left landing skid. Both helicopters were operated under the provisions of 14 Code of Federal Regulations Part 91as personal flights. Visual meteorological conditions prevailed.The flight of helicopters, each designated "Chalk 1" through "Chalk 5," were enroute to an annual all-helicopter airshow. The pilots of Chalk 1, 3, and 4 provided written statements, and their statements were consistent throughout. They each said that "Flight Lead," Chalk 5 was flying in the trail aircraft position. According to their statements, the flight arrived in trail formation and overflew runway 09 at 1,200 feet and 60 knots. Chalk 1 stated he entered left traffic, and while on the left base leg for landing, Chalk 3 announced airplane traffic on final approach to Runway 09. Chalk 1 stated he turned left prior to the runway, and initiated a go-around on the north side of the runway. Flight lead, in the trail aircraft, then announced over the flight's internal radio frequency to, "Break left or land." According to Chalk 3, he then "initiated a steep approach" to land on runway 09, and while he maintained visual separation from Chalk 2, noticed the rotor disk of another helicopter immediately below and to the right of his just as contact between the two was made, which separated the left landing gear skid. Chalk 3 then egressed his passengers from a hover, and repositioned the helicopter back to LNS and sought the assistance air traffic control (ATC) and crash/fire/rescue services. The helicopter landed without further incident. According to Chalk 4, Chalk 1 announced a go-around, but Chalk 5 gave the command to break left or land. At that point, he had Chalks 1, 2, and 3 in sight. Chalk 4 then confirmed the airplane traffic was "no factor" and had initiated a go-around on the south side of the runway. When he looked back on the formation in front of him, he had only Chalk 2 in sight, and had lost visual contact with Chalks 1 and 3. Chalk 4 then performed a "normal" approach to a 5-foot hover over the runway centerline, began a hover-taxi to parking, and about 20 seconds later "felt" the contact with the other helicopter. He then landed the helicopter without further incident. The pilot of Chalk 4 held a private pilot certificate, with a rating for a rotorcraft-helicopter. He reported 586 total hours of flight experience, of which 253 hours were in the accident helicopter make and model. The pilot of Chalk 3 held a commercial pilot certificate, with a rating for a rotorcraft-helicopter. He reported 1,617total hours of flight experience, 92 hours of which were in the accident helicopter make and model. Each of the accident helicopters had 100-hour inspections performed during the year prior to the accident, and each pilot reported there were no mechanical deficiencies with either helicopter that would have prevented normal operation. Examination of briefing slides provided to the group by the flight lead (Chalk 5) revealed that the aircraft position order briefed on the slides was not the order flown. There were no slides that provided guidance for loss of visual contact or an inadvertent encounter with instrument meteorological conditions. There was no slide that identified flight lead would fly from the trail position of the formation.

On October 13, 2012, about 0920 eastern daylight time, two helicopters in a flight of five, a Hughes 369A, N369SN (Chalk 3), and another Hughes 369A, N546 (Chalk 4), collided during hover-taxi while landing at Brandywine Airport (OQN), West Chester, Pennsylvania. The 3 occupants in Chalk 3 and the 2 occupants in Chalk 4 were not injured. Chalk 4 sustained substantial damage to all four main rotor blades and the tail pylon. Chalk 3 sustained substantial damage to the left landing skid. Both helicopters were operated under the provisions of 14 Code of Federal Regulations Part 91as personal flights. Visual meteorological conditions prevailed. The helicopters were part of a flight of 5 helicopters that attended an annual all-helicopter airshow.The pilots of Chalk 1, 3, and 4 provided written statements and their statements were consistent throughout. They each said that "Flight Lead" was in Chalk 5; the trail aircraft. According to their statements, the flight arrived in trail formation and overflew runway 09 at 1200 feet and 60 knots. Chalk 1 stated he entered left traffic, and while on the left base leg for landing, Chalk 3 announced airplane traffic on final approach to Runway 09. Chalk 1 stated he turned left prior to the runway, and initiated a go-around on the north side of the runway. Flight lead, in the trail aircraft, then announced over the flight's internal radio frequency to, "Break left or land." According to Chalk 3, he then "initiated a steep approach" to land on runway 09, and while he maintained visual separation from Chalk 2, noticed the rotor disk of another helicopter immediately below and to the right of his just as contact between the two was made, which separated the left landing gear skid. Chalk 3 then egressed his passengers from a hover, and repositioned the helicopter back to LNS in order to avail him of air traffic control and crash/fire/rescue services. The helicopter landed without further incident. According to Chalk 4, Chalk 1 announced a go-around, but Chalk 5 gave the command to break left or land. At that point, he had Chalks 1, 2, and 3 in sight. Chalk 4 then confirmed the airplane traffic was "no factor" and had initiated a go-around on the south side of the runway. When he looked back on the formation in front of him, he had only Chalk 2 in sight, and had lost visual contact with Chalks 1 and 3. Chalk 4 then performed a "normal" approach to a 5-foot hover over the runway centerline, began a hover-taxi to parking, and about 20 seconds later "felt" the contact with the other helicopter. He then landed the helicopter without further incident. The pilot of Chalk 4 held a private pilot certificate, with a rating for a rotorcraft-helicopter. He reported 586 total hours of flight experience, of which 253 hours were in the accident helicopter make and model. The pilot of Chalk 3 held a commercial pilot certificate, with a rating for a rotorcraft-helicopter. He reported 1,617 total hours of flight experience, 92 hours ofwhich were in the accident helicopter make and model. Each of the accident helicopters had 100-hour inspections performed during the year prior to the accident, and each pilot reported there were no mechanical deficiencies with either helicopter that would have prevented normal operation. Examination of the Rotorfest 2012 Briefing slides revealed that the Chalk order briefed on the slides was not the Chalk order flown. There was no slide that provided guidance for loss of visual contact or inadvertent IMC procedures. There was no slide that identified "Flight Lead" would fly from the trail position of the formation. Examination of military and Formation and Safety Team (FAST) training documents revealed that flight lead was always the lead aircraft in a given multi-ship formation. While the air mission commander (AMC) may fly from any position in the formation, the lead aircraft always maintained the role of flight lead. Following in-flight formation changes, the aircraft assuming the lead position in the flight, assumed the role of flight lead. Army Field Manual (FM 3-04.203) Fundamentals of Flight, Chapter 6, Multi-Aircraft Operations stated: FLIGHT LEAD (TEAM LEAD) 6-8. Flight (team) lead and wingman are roles flight members fulfill based upon their positions within the flight. Team lead is used to denote the flight lead for two aircraft operating in teams. Flight lead is the formation leader designated by the AMC and is generally the most proficient PC (pilot in command). Flight leads are selected based on ability and demonstrated knowledge of missions and tactics, and local SOPs. The flight lead's responsibilities include navigation, en route communication (between flight members, ATC, and supported units), obstacle and threat avoidance, wingmen position awareness, and the energy states of all aircraft. The AMC may delegate some of these duties throughout the flight. Chalk 2 should always be prepared to lead the flight. FORMATION LANDING 6-41. All aircraft touch down at the same time while maintaining their relative positions within the flight. The rate of closure throughout approach and landing is somewhat slower at night than during the day. Flight lead should maintain straight-and-level flight until the desired approach angle is intercepted. Lead then maintains a constant approach angle and, where terrain and obstacles permit, makes the approach to the ground avoiding hovering turbulence and brownout or whiteout conditions. If the rate of closure is too fast, the aviator should avoid S-turns to lose airspeed. Instead, execute a go-around if unable to slow to the appropriate airspeed, especially with heavily loaded aircraft. 6-42. Lead must plan to touch down far enough forward in the PZ/LZ to provide sufficient landing space for the entire flight.

Aircraft · 2

Registration
N546
Reported as
Hughes/Helicopter Assocs 369A
Category
Helicopter
Serial number
HA001
Built
1997
Airframe hours
1,154
Engine
Rolls-Royce 250-C10D, 317 horsepower, turbo shaft
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · December 31, 2011 · 94 hours before
Departed
LNS · Lancaster, PA
Destination
OQN · West Chester, PA
Airport
OQN · Brandywine, runway 09, 3,347 × 50 ft, asphalt

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Registration
N369SN
Reported as
Hughes 369A
Category
Helicopter
Serial number
66-14389
Built
1968
Airframe hours
4,386
Engine
Allison/RR 250-C10D, 317 horsepower, turbo shaft
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · October 8, 2012
Departed
LNS · Lancaster, PA
Destination
OQN · West Chester, PA
Airport
OQN · Brandywine, runway 09, 3,347 × 50 ft, asphalt

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew · 2

As NTSB recorded them. NTSB leaves out names.

Role
Pilot, aircraft N546
Age
57
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, With waivers/limitations
Last flight review
February 28, 2012
Seat
Right
Flight hours
586 total · 253 in this make and model · 379 as pilot in command · 32 in the last 90 days · 17 in the last 30 days · 3 in the last 24 hours
Role
Pilot, aircraft N369SN
Age
49
Injuries
None
Certificates
Private, Commercial, Flight instructor
Airplane ratings
Single-engine land
Medical
Class 2, With waivers/limitations
Last flight review
April 2, 2012
Seat
Right
Flight hours
1,617 total · 92 in this make and model · 1,458 as pilot in command · 29 in the last 90 days · 22 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
None
Temperature
43 °F
Altimeter
30.53 inHg
Observed at
LNS, 35 nm away

Docket · 7

The files NTSB released with the investigation on February 3, 2016, on NTSB’s docket system: statements, records, photos and specialists’ reports. 4.0 MB in all.

FAA reports on this event · 2

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.