# NTSB DEN85IA250: Boeing 727-100, N721PC, Denver, CO, September 30, 1985

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: September 29, 1985, 18:40 local (Sep 30, 1985, 00:40 UTC)
- Place: Denver, CO
- Coordinates: 39.729358, -104.919486 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.7294&lon=-104.9195&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 71 uninjured
- Status: Completed
- Report: Approved by Office Director
- Safety recommendations: Yes
- ADs cited in the narratives: AD 68-17-01 (OpenAirDocs)
- NTSB case key (mKey): 16585
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN85IA250
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16585/pdf
- Page: https://openairdocs.org/ntsb/DEN85IA250

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach - faf/outer marker to threshold (ifr)
  - maintenance,service bulletin/letter - not followed, other maintenance personnel (contributing factor)
  - maintenance,recordkeeping - improper, other maintenance personnel (cause)
  - landing gear,normal retraction/extension assembly - corroded (cause)
  - maintenance,compliance with ad - not performed (cause)
  - landing gear,normal retraction/extension assembly - failure,partial (cause)

## Analysis

DURING GEAR EXTN FOR LNDG, THE FLT CREW NOTED A 'LOUD & VERY NOTICEABLE JOLTING OF THE ACFT.'  SHORTLY THEREAFTER, THEY ALSO NOTICED THAT A PORTION OF THE RIGHT MAIN GEAR HAD PUNCTURED THE UPPER SURFACE OF THE RGT WING. THE CREW THEN DECLARED AN EMERGENCY & MADE AN UNEVENTFUL LNDG. AN INVESTIGATION REVEALED THE RGT MAIN GEAR ACTUATOR SUPPORT LINK, PN 65-19657-5, HAD BECOME CORRODED & FAILED. THE OUTBOARD END OF THE MAIN GEAR ACTUATOR BEAM THEN PUNCTURED THE UPPER WING PANEL. ALSO A HYDRAULIC LINE WAS SEVERED, WHICH DISABLED THE 'A' HYDRAULIC SYS. MAINTENANCE RECORDS FROM THE PREVIOUS ACFT OWNER ERRONEOUSLY INDICATED THAT IN 1971, THE FAILED PART HAD BEEN REPLACED WITH A NEWER LINK ASSEMBLY, PN 19657-11, WHICH DID NOT REQUIRE AN INSPECTION. CONSEQUENTLY, THE REQUIRED INSPECTIONS SPECIFIED IN AD 68-17-01, REGARDING THE FAILED LINK, HAD NOT BEEN COMPLIED WITH BY THE NEW OWNER. BOEING HAD ISSUED A SVC BULLETIN (727-32-306) WHICH RECOMMENDED THAT LINK ASSEMBLIES WITH PN 19657-5 (AS WELL AS -4, -8 & -13) BE REMOVED FROM SVC & DISCARDED.

## Aircraft

- Registration: N721PC (not matched to a registry record)
- Reported make and model: BOEING 727-100
- Category: Airplane
- Serial number: 18997
- Airframe hours: 30204
- Engines: P&W JT8D-7B 14000 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 121
- Registered owner: Ports Of Call Travel Club
- Airworthiness certificate: Standard, Transport; Standard, Normal
- Last inspection: Continuous airworthiness, September 26, 1983
- Departed: PVR, PUERTO VALLARTO, OF
- Destination: DEN
- Flight plan: IFR
- Airport: DEN, Stapleton, runway 17L, 12,000 × 200 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 54; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 13,000 total, 300 in this make and model, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 100° at 5 knots
- Visibility: 15 statute miles
- Lowest ceiling: 4,000 ft overcast
- Temperature: 27 °F, dew point 18 °F
- Altimeter: 30.00 inHg
- Observed at: DEN

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19850929055259I](https://openairdocs.org/incident/19850929055259I), Sep 29, 1985: Boeing 72721, Denver, CO, Minor damage. Gear actuator beam and support link assembly were forced through upper wing skin on gear extension due corrosion.

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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