# NTSB MIA93LA088: Christen Industries Pitts S1-T, N218MC, Naples, FL, March 21, 1993

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: March 21, 1993, 11:42 local (16:42 UTC)
- Place: Naples, FL
- Location: 26.1640° N, 81.7659° W: Placed by OpenAirDocs from NTSB’s distance and direction from NAPLES MUNI (APF), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=26.1640&lon=-81.7659&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report February 10, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 33243
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA93LA088
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33243/pdf
- Page: https://openairdocs.org/ntsb/MIA93LA088

## Probable cause

THE INSTALLATION OF AN IMPROPER DESIGNED INTAKE TUBE AND AIR FILTER BY THE NONMECHANIC RATED PILOT-IN-COMMAND, WHICH RESULTED IN MOISTURE BUILD UP AND COLLAPSE OF THE AIR FILTER, WHICH RESULTED IN BLOCKAGE OF AIR FLOW TO THE ENGINE AND LOSS OF ENGINE POWER. CONTRIBUTING TO THE ACCIDENT WAS THE FAILURE OF THE PILOT-IN-COMMAND TO MAINTAIN AIRSPEED AND FLARE PROPERLY DURING A FORCED LANDING.

## Sequence of events

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

- Loss of engine power(partial) - nonmechanical, takeoff - initial climb
  - induction air ducting - inadequate (cause)
  - maintenance,installation - improper, unqualified person (cause)
  - acft/equip,inadequate design, manufacturer (cause)
  - induction air control,air filter/screen - inadequate (cause)
  - maintenance,installation - improper, unqualified person (cause)
  - induction air control,air filter/screen - collapsed (contributing factor)
  - induction air control,air filter/screen - blocked(partial) (contributing factor)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown
  - airspeed - not maintained, pilot in command (cause)
  - flare - improper, pilot in command (cause)
- Nose over, landing - flare/touchdown

## Analysis

THE PILOT, WHO DOES NOT HOLD AN AIRFRAME OR POWERPLANT MECHANIC'S LICENSE STATED HE INSTALLED A STRAIGHT AIR INTAKE TUBE ON HIS AIRCRAFT. THIS TUBE DID NOT HAVE ANY MEANS FOR ALTERNATE AIR OR FILTERING OF INCOMING AIR. HE FURTHER MODIFIED THE TUBE BY INSTALLING A SCREEN AND A PIECE OF AIR FILTERING MATERIAL IN THE TUBE. DURING THE FIRST TAKEOFF AFTER THE MODIFICATION THE AIRCRAFT CLIMBED TO 200 FEET, AT WHICH TIME THE MANIFOLD PRESSURE DROPPED AND THE ENGINE LOST POWER. HE WAS UNABLE TO MAINTAIN ALTITUDE AND THE AIRCRAFT TOUCHED DOWN HARD ON THE RUNWAY AND NOSED OVER INVERTED. POSTCRASH EXAMINATION AND TESTING OF THE INTAKE TUBE WAS PERFORMED BY AN FAA INSPECTOR. WHEN A VACUUM CLEANER WAS ATTACHED TO THE ENGINE SIDE OF THE INTAKE TUBE AND TURNED ON THE AIR FLOW THROUGH THE TUBE WAS NORMAL FOR SEVERAL MINUTES. AFTER THIS, MOISTURE BUILT UP ON THE AIR FILTERING MATERIAL AND THE FILTER COLLAPSED. THE VACUUM CLEANER THEN BEGAN TO STRAIN DUE TO LACK OF AIR FLOW.

## Aircraft

- Registration: [N218MC](https://openairdocs.org/deregistered/N218MC-2011-01-26), registration cancelled 2011-01-26, S/N 1041 (OpenAirDocs)
- Reported make and model: Christen Industries PITTS S1-T
- Registry model: [Christen Industries PITTS S-1T](https://openairdocs.org/model/christen-industries-pitts-s-1t) (registry code 2210002) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Airplane
- Serial number: 1041
- Airframe hours: 470
- Engines: LYCOMING AEIO-360 200 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Cutshaw, Michael H.
- Registered owner: Cutshaw, Michael H.
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, June 20, 1992, 25 hours before
- Departed: APF
- Airport: APF, Naples Municipal, runway 4, 5,000 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 14,000 total, 350 in this make and model, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 100° at 3 knots
- Visibility: 10 statute miles
- Lowest ceiling: 4,000 ft broken
- Temperature: 75 °F, dew point 66 °F
- Altimeter: 30.00 inHg
- Observed at: APF, 1 nm away

## FAA reports on this event (1)

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

- [Accident 19930321005679A](https://openairdocs.org/incident/19930321005679A), Mar 21, 1993: Child S1TPITTS, Naples, FL, Substantial damage. Lost power on takeoff. Crash landed on side of runway. Had installed wrong engine air intake. Cut off air to engine

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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