# NTSB LAX91GA016: McDonnell Douglas 369E, N451DS, Compton, CA, October 24, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: October 23, 1990, 19:46 local (Oct 24, 1990, 02:46 UTC)
- Place: Compton, CA
- Coordinates: 33.869327, -118.240325 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.8693&lon=-118.2403&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed, report May 10, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27028
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91GA016
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27028/pdf
- Page: https://openairdocs.org/ntsb/LAX91GA016

## Probable cause (aircraft 2)

INADEQUATE VISUAL LOOKOUT BY THE PILOTS OF BOTH AIRCRAFT, WHICH RESULTED IN A FAILURE OF EACH TO SEE-AND-AVOID CONFLICTING TRAFFIC.  FACTORS RELATED TO THE ACCIDENT WERE: DARKNESS, FAILURE OF THE PILOT OF AIR 28 (N48HR) TO USE HIS TRANSPONDER NEAR THE TCA, AND THE PILOT OF AIR 21 DIVERTED TOO MUCH OF HIS ATTENTION TO A MAP.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Midair collision, cruise
  - light condition - night (contributing factor)
  - visual lookout - inadequate, pilot in command (cause)
  - diverted attention, pilot in command (contributing factor)
  - visual lookout - inadequate, pilot of other aircraft (cause)
  - procedures/directives - not followed, pilot of other aircraft (contributing factor)
- Forced landing, descent - emergency
- Midair collision, maneuvering
  - light condition - night (contributing factor)
  - visual lookout - inadequate, pilot in command (cause)
  - procedures/directives - not followed, pilot in command (contributing factor)
  - visual lookout - inadequate, pilot of other aircraft (cause)
  - diverted attention, pilot of other aircraft (contributing factor)
- Forced landing, descent - emergency

## Analysis (aircraft 2)

TWO HELICOPTERS WERE BEING USED IN LAW ENFORCEMENT ACTIVITIES. ONE WAS A LOS ANGELES SHERIFF'S DEPT (LASD) MCDONNELL- DOUGLAS 369E, N451DS, CALL SIGN AIR 21. THE OTR WAS A COMPTON POLICE DEPT (CPD) ENSTROM F-28F, N48HR, CALL SIGN AIR 28. WHILE IN THE LAX TCA, AIR 21 RESPONDED TO AN EMERG CALL. AFTER DEPG THE TCA, THE PLT (AIR 21) SWITCHED HIS COM RADIO TO 123.02 MHZ (COMMON FREQ FOR LAW ENFORCEMENT IN THE AREA) & ANNOUNCED HIS PSN. WHEN NO RESPONSE WAS RCVD, HE SWITCHED TO THE COMPTON UNICOM FREQ (122.9 MHZ).  AT ABOUT THAT TIME, AIR 28 WAS ORBITING IN THE SAME VCNTY. THE PLT OF AIR 28 SAID HE HAD ANNOUNCED HIS PSN ON 122.9 MHZ (RQRD FREQ IN THE AREA FOR CPD ACFT) & WAS MONITORING 123.02 MHZ. THE 2 CONVERGED & COLLIDED, BUT BOTH REMAINED CONTROLLABLE & WERE LNDD FROM EMERG APCHS. BFR THE MIDAIR, THE PLT OF AIR 21 WAS HELPING HIS OBSERVER LOOK FOR A PSN ON A MAP. HE SAW AIR 28 JUST BFR IMPACT, BUT NOT IN TIME TO AVOID A COLLISION. THE PLT OF AIR 28 HAD HIS TRANSPONDER ON STANDBY, ALTHO HE WAS REQD TO BE OPERG IT, WHILE WITHIN 30 MI OF THE (GROUP 1) TCA.

## Aircraft 1

- Registration: N451DS (not matched to a registry record)
- Reported make and model: McDonnell Douglas 369E
- Category: Helicopter
- Serial number: 0251E
- Airframe hours: 3168
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Public aircraft, Part 91
- Operator: Los Angeles Sheriff Dept.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, September 28, 1990, 75 hours before
- Departed: NONE, CARSON, CA

## Aircraft 2

- Registration: N48HR (not matched to a registry record)
- Reported make and model: ENSTROM F-28F
- Category: Helicopter
- Serial number: 755
- Airframe hours: 1986
- Engines: LYCOMING HIO-360-F1AD 225 horsepower reciprocating
- Damage: Substantial damage
- Flight: Public aircraft, Part 91
- Operator: Compton Police Department
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, October 17, 1990
- Departed: CPM, COMPTON, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot, aircraft N451DS; age 43; commercial, private; airplane ratings: single-engine land, multi-engine land; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 3,734 total, 2,981 in this make and model, 3,662 as pilot in command, 263 in the last 90 days, 71 in the last 30 days, 5 in the last 24 hours
- Pilot, aircraft N48HR; age 35; private; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 233 total, 233 in this make and model, 148 as pilot in command, 217 in the last 90 days, 26 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/bright
- Wind: 250° at 9 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 70 °F
- Altimeter: 29.00 inHg

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.

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