NTSB investigations, 2010
176 cases where the phase of flight was Approach.
Cases per year
| 1962 | 14 |
|---|---|
| 1963 | 10 |
| 1964 | 530 |
| 1965 | 502 |
| 1966 | 600 |
| 1967 | 640 |
| 1968 | 597 |
| 1969 | 572 |
| 1970 | 583 |
| 1971 | 550 |
| 1972 | 522 |
| 1973 | 543 |
| 1974 | 541 |
| 1975 | 530 |
| 1976 | 504 |
| 1977 | 586 |
| 1978 | 567 |
| 1979 | 541 |
| 1980 | 508 |
| 1981 | 473 |
| 1982 | 433 |
| 1983 | 445 |
| 1984 | 433 |
| 1985 | 408 |
| 1986 | 382 |
| 1987 | 327 |
| 1988 | 342 |
| 1989 | 324 |
| 1990 | 334 |
| 1991 | 308 |
| 1992 | 291 |
| 1993 | 276 |
| 1994 | 251 |
| 1995 | 301 |
| 1996 | 272 |
| 1997 | 261 |
| 1998 | 238 |
| 1999 | 244 |
| 2000 | 256 |
| 2001 | 230 |
| 2002 | 232 |
| 2003 | 236 |
| 2004 | 216 |
| 2005 | 229 |
| 2006 | 225 |
| 2007 | 258 |
| 2008 | 211 |
| 2009 | 190 |
| 2010 | 176 |
| 2011 | 194 |
| 2012 | 181 |
| 2013 | 189 |
| 2014 | 178 |
| 2015 | 158 |
| 2016 | 160 |
| 2017 | 191 |
| 2018 | 172 |
| 2019 | 163 |
| 2020 | 156 |
| 2021 | 178 |
| 2022 | 204 |
| 2023 | 186 |
| 2024 | 164 |
| 2025 | 186 |
| 2026 | 88 |
Where
Latest cases
Query with SQL
duckdb -csv -c "WITH phase_names(main, name) AS (VALUES (100, 'Prior to flight'), (150, 'Standing'), (200, 'Pushback/towing'), (250, 'Taxi'), (300, 'Takeoff'), (350, 'Initial climb'), (400, 'Enroute'), (450, 'Maneuvering'), (500, 'Approach'), (550, 'Landing'), (600, 'Emergency descent'), (650, 'Uncontrolled descent'), (700, 'Post-impact'), (750, 'After landing'), (800, 'Other'), (990, 'Unknown')),
crosswalk(code, main, name) AS (VALUES (500, 150, 'Standing'), (501, 150, 'Standing - pre-flight'), (502, 150, 'Standing - starting engine(s)'), (503, 150, 'Standing - engine(s) operating'), (504, 150, 'Standing - engine(s) not operating'), (505, 150, 'Standing - idling rotors'), (510, 250, 'Taxi'), (511, 200, 'Taxi - pushback/tow'), (512, 250, 'Taxi - to takeoff'), (513, 250, 'Taxi - from landing'), (514, 250, 'Taxi - aerial'), (520, 300, 'Takeoff'), (521, 300, 'Takeoff - roll/run'), (522, 350, 'Takeoff - initial climb'), (523, 300, 'Takeoff - aborted'), (530, 400, 'Climb'), (531, 400, 'Climb - to cruise'), (540, 400, 'Cruise'), (541, 400, 'Cruise - normal'), (542, 400, 'Maneuvering - holding (IFR)'), (550, 400, 'Descent'), (551, 400, 'Descent - normal'), (552, 600, 'Descent - emergency'), (553, 650, 'Descent - uncontrolled'), (560, 500, 'Approach'), (561, 500, 'Approach - VFR pattern - downwind'), (562, 500, 'Approach - VFR pattern - base turn'), (563, 500, 'Approach - VFR pattern - base leg/base to final'), (564, 500, 'Approach - VFR pattern - final approach'), (565, 500, 'Go-around (VFR)'), (566, 500, 'Approach - IAF to FAF/outer marker (IFR)'), (567, 500, 'Approach - FAF/outer marker to threshold (IFR)'), (568, 500, 'Circling (IFR)'), (569, 500, 'Missed approach (IFR)'), (570, 550, 'Landing'), (571, 550, 'Landing - flare/touchdown'), (572, 550, 'Landing - roll'), (573, 550, 'Landing - aborted'), (574, 550, 'Emergency landing'), (575, 550, 'Emergency landing after takeoff'), (576, 600, 'Emergency descent/landing'), (580, 450, 'Maneuvering'), (581, 450, 'Maneuvering - aerial application'), (582, 450, 'Maneuvering - turn to reverse direction'), (583, 450, 'Maneuvering - turn to landing area (emergency)'), (590, 450, 'Hover'), (591, 450, 'Hover - in ground effect'), (592, 450, 'Hover - out of ground effect'), (600, 800, 'Other'), (610, 990, 'Unknown')),
current_codes AS (
SELECT e.case_mkey, TRY_CAST(e.\"tier1Number\" AS INTEGER) AS code,
row_number() OVER (PARTITION BY e.case_mkey ORDER BY coalesce(e.\"isDefiningEvent\", false) DESC, e.position) AS n
FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' e
WHERE e.aircrafts_position = 1 AND e.\"tier1Number\" GLOB '[1-9][0-9]*'
AND (e.\"isDefiningEvent\" OR e.case_mkey IN (SELECT \"mKey\" FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' WHERE \"isPre1982\"))
),
phases AS (
SELECT case_mkey, 'current' AS scheme, code, CASE WHEN code >= 990 THEN 990 ELSE code // 50 * 50 END AS main
FROM current_codes WHERE n = 1
UNION ALL
SELECT o.case_mkey, 'older', o.\"phaseOfFlightCode\", w.main
FROM 'https://openairdocs.org/data/latest/ntsb_occurrences.parquet' o JOIN crosswalk w ON w.code = o.\"phaseOfFlightCode\"
WHERE o.aircrafts_position = 1 AND o.\"occurrenceNumber\" = 1 AND o.case_mkey NOT IN (SELECT case_mkey FROM current_codes)
),
case_phases AS (
SELECT p.*, c.\"eventDate\", c.\"highestInjuryLevel\" = 'Fatal' AS fatal, a.aircraft_model_code
FROM phases p JOIN 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c ON c.\"mKey\" = p.case_mkey
LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = p.case_mkey AND a.position = 1
WHERE c.\"eventDate\" >= DATE '1962-01-01' AND p.main IN (SELECT main FROM phase_names)
)
SELECT c.\"ntsbNumber\", c.\"eventDate\", c.\"eventType\", c.\"eventCity\", c.\"eventStateOrRegion\", a.n_number, a.\"aircraftMake\", a.\"aircraftModel\", c.\"highestInjuryLevel\", c.\"totalFatal\", c.\"completionStatus\", c.report_url
FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = c.\"mKey\" AND a.position = 1
WHERE year(c.\"eventDate\") = 2010
AND c.\"mKey\" IN (SELECT case_mkey FROM case_phases WHERE main = 500)
ORDER BY c.\"eventDate\" DESC, c.\"ntsbNumber\" DESC"Prints the whole list as CSV. It reads the release’s Parquet files over HTTPS, so there’s nothing to download first. Install DuckDB to run it.
WITH phase_names(main, name) AS (VALUES (100, 'Prior to flight'), (150, 'Standing'), (200, 'Pushback/towing'), (250, 'Taxi'), (300, 'Takeoff'), (350, 'Initial climb'), (400, 'Enroute'), (450, 'Maneuvering'), (500, 'Approach'), (550, 'Landing'), (600, 'Emergency descent'), (650, 'Uncontrolled descent'), (700, 'Post-impact'), (750, 'After landing'), (800, 'Other'), (990, 'Unknown')),
crosswalk(code, main, name) AS (VALUES (500, 150, 'Standing'), (501, 150, 'Standing - pre-flight'), (502, 150, 'Standing - starting engine(s)'), (503, 150, 'Standing - engine(s) operating'), (504, 150, 'Standing - engine(s) not operating'), (505, 150, 'Standing - idling rotors'), (510, 250, 'Taxi'), (511, 200, 'Taxi - pushback/tow'), (512, 250, 'Taxi - to takeoff'), (513, 250, 'Taxi - from landing'), (514, 250, 'Taxi - aerial'), (520, 300, 'Takeoff'), (521, 300, 'Takeoff - roll/run'), (522, 350, 'Takeoff - initial climb'), (523, 300, 'Takeoff - aborted'), (530, 400, 'Climb'), (531, 400, 'Climb - to cruise'), (540, 400, 'Cruise'), (541, 400, 'Cruise - normal'), (542, 400, 'Maneuvering - holding (IFR)'), (550, 400, 'Descent'), (551, 400, 'Descent - normal'), (552, 600, 'Descent - emergency'), (553, 650, 'Descent - uncontrolled'), (560, 500, 'Approach'), (561, 500, 'Approach - VFR pattern - downwind'), (562, 500, 'Approach - VFR pattern - base turn'), (563, 500, 'Approach - VFR pattern - base leg/base to final'), (564, 500, 'Approach - VFR pattern - final approach'), (565, 500, 'Go-around (VFR)'), (566, 500, 'Approach - IAF to FAF/outer marker (IFR)'), (567, 500, 'Approach - FAF/outer marker to threshold (IFR)'), (568, 500, 'Circling (IFR)'), (569, 500, 'Missed approach (IFR)'), (570, 550, 'Landing'), (571, 550, 'Landing - flare/touchdown'), (572, 550, 'Landing - roll'), (573, 550, 'Landing - aborted'), (574, 550, 'Emergency landing'), (575, 550, 'Emergency landing after takeoff'), (576, 600, 'Emergency descent/landing'), (580, 450, 'Maneuvering'), (581, 450, 'Maneuvering - aerial application'), (582, 450, 'Maneuvering - turn to reverse direction'), (583, 450, 'Maneuvering - turn to landing area (emergency)'), (590, 450, 'Hover'), (591, 450, 'Hover - in ground effect'), (592, 450, 'Hover - out of ground effect'), (600, 800, 'Other'), (610, 990, 'Unknown')),
current_codes AS (
SELECT e.case_mkey, TRY_CAST(e."tier1Number" AS INTEGER) AS code,
row_number() OVER (PARTITION BY e.case_mkey ORDER BY coalesce(e."isDefiningEvent", false) DESC, e.position) AS n
FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' e
WHERE e.aircrafts_position = 1 AND e."tier1Number" GLOB '[1-9][0-9]*'
AND (e."isDefiningEvent" OR e.case_mkey IN (SELECT "mKey" FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' WHERE "isPre1982"))
),
phases AS (
SELECT case_mkey, 'current' AS scheme, code, CASE WHEN code >= 990 THEN 990 ELSE code // 50 * 50 END AS main
FROM current_codes WHERE n = 1
UNION ALL
SELECT o.case_mkey, 'older', o."phaseOfFlightCode", w.main
FROM 'https://openairdocs.org/data/latest/ntsb_occurrences.parquet' o JOIN crosswalk w ON w.code = o."phaseOfFlightCode"
WHERE o.aircrafts_position = 1 AND o."occurrenceNumber" = 1 AND o.case_mkey NOT IN (SELECT case_mkey FROM current_codes)
),
case_phases AS (
SELECT p.*, c."eventDate", c."highestInjuryLevel" = 'Fatal' AS fatal, a.aircraft_model_code
FROM phases p JOIN 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c ON c."mKey" = p.case_mkey
LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = p.case_mkey AND a.position = 1
WHERE c."eventDate" >= DATE '1962-01-01' AND p.main IN (SELECT main FROM phase_names)
)
SELECT c."ntsbNumber", c."eventDate", c."eventType", c."eventCity", c."eventStateOrRegion", a.n_number, a."aircraftMake", a."aircraftModel", c."highestInjuryLevel", c."totalFatal", c."completionStatus", c.report_url
FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = c."mKey" AND a.position = 1
WHERE year(c."eventDate") = 2010
AND c."mKey" IN (SELECT case_mkey FROM case_phases WHERE main = 500)
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESCRun it at the DuckDB prompt, or in any tool that reads Parquet over HTTPS. More ways to query the release are on Use the data.
NTSB CEN11CA132Accident · No injuriesData collectionFinal reportCessna T210L · Abilene, TXThe pilot’s improper fuel management, which resulted in a loss of engine power due to fuel exhaustion.NTSB CEN11CA136Accident · Minor injuriesData collectionFinal reportAero Commander 500-B · Columbus, OHThe pilot’s improper fuel management which resulted in a loss of engine power due to fuel exhaustion.NTSB ERA11FA095Accident · 1 fatalField investigationFinal reportMooney M20R · Dundee, NYThe pilot's decision to operate in known moderate-to-severe icing conditions, which resulted in a loss of control during approach.NTSB CEN11FA124Accident · 2 fatalField investigationFinal reportMooney M20E · Colorado Springs, COThe pilot’s decision to initiate an approach into weather conditions where the ceiling and visibility were below the minimums for the approach and where reported icing existed, in an airplane not certified for flight in icing conditions, and his failure to…NTSB ERA11WA098Accident · 1 fatalForeign investigationBell 206 · Aracuju, BrazilOn December 21, 2010, about 1300 universal coordinated time, a Bell 206B, Brazilian registration PR-HQB, during an approach for landing; encountered a strong wind gust, impacted the terrain, and was substantially damaged in Aracaju, Segripe, Brazil. The pilot…NTSB CEN11CA128Accident · No injuriesData collectionFinal reportCessna 340A · Madison, WIThe pilot's failure to maintain adequate airspeed during the approach, which resulted in an aerodynamic stall. Contributing to the accident was the pilot's failure to check the de-ice fluid level prior to takeoff, which resulted in the failure of the de-ice…NTSB CEN11LA148Accident · No injuriesLimited investigationFinal reportBeech H35 · Des Moines, IAA total loss of engine power due to fuel exhaustion as a result of the pilot's inadequate fuel planning.NTSB CEN11FA110Accident · 2 fatalField investigationFinal reportBeech B60 · Edwards, COControlled flight into terrain, while on an instrument approach in instrument meteorological conditions, for undetermined reasons.NTSB ERA11WA090Accident · 2 fatalForeign investigationHawker Beechcraft TC-45J · Nassau, BahamasOn December 14, 2010, about 1442 eastern standard time, a Hawker Beechcraft TC-45J, N38L, registered to and operated by Monarch Air Group, impacted ocean waters about 7 miles southwest of Lynden Pindling International Airport (MYNN), Nassau, Bahamas. The…NTSB WPR11LA076Accident · Serious injuriesLimited investigationFinal reportTaylorcraft BC12-65 · College Place, WAThe pilot's failure to abort the landing when he lost sight of the runway due to sun glare, and his inadequate compensation for the crosswind.NTSB CEN11IA108Incident · No injuriesIncident investigationFinal reportPiaggio P180 · Columbus, OHThe failure of water to properly drain through the fuselage drain holes, thus becoming trapped and freezing around the flight control cables, which resulted in the loss of control authority to the airplane's ailerons, elevator, and rudder.NTSB WPR11FA073Accident · Serious injuriesField investigationFinal reportCessna T210M · Ogden, UTThe pilot did not maintain clearance from obstacles after descending below the published approach decision height when visibility was less than published approach minimums due to heavy ground fog and he did not execute a missed approach after failing to…NTSB ERA11IA091Incident · No injuriesIncident investigationFinal reportEurocopter Deutschland MBB-BK 117 C-1 · Boston, MAImproper installation of wiring associated with a medical cabinet interior, which resulted in chafing and a subsequent in-flight fire. Contributing to the incident was inadequate maintenance procedures for continued airworthiness.NTSB CEN11LA089Accident · No injuriesLimited investigationFinal reportCessna 180 · Omaha, NEA loss of engine power due to a stuck check valve in the carburetor acceleration pump, resulting in an improper fuel mixture when the pilot attempted to add power.NTSB WPR11LA068Accident · No injuriesLimited investigationFinal reportTaylorcraft BC-65 · Madras, ORThe failure of both pilots to see and avoid the other airplane while in the traffic pattern to land, which resulted in a midair collision.NTSB CEN11LA086Accident · 1 fatalLimited investigationFinal reportMaule M-5-180C · Emory, TXThe pilot's loss of control and failure to attain/maintain adequate airspeed during an attempted go-around after a hard bounced landing, resulting in an aerodynamic stall. Contributing to the accident was the pilot’s recent minimal experience in airplane…NTSB WPR11LA062Accident · Minor injuriesLimited investigationFinal reportCessna 172E · Suisun City, CAA total loss of engine power for undetermined reasons.NTSB ERA11FA070Accident · 3 fatalField investigationFinal reportPiper PA 46-350P · Destin, FLControlled flight into water due to the pilot's improper descent below the published minimum descent altitude.NTSB WPR11FA054Accident · 3 fatalField investigationFinal reportBeech 19A · Newport Beach, CAThe pilot's inadequate fuel planning, which resulted in a total loss of engine power due to fuel exhaustion.NTSB ERA11GA066Accident · 3 fatalFinal reportCessna M337B · Avon Park, FLThe pilot's inadvertent encounter with an unexpected intense rain shower with severe turbulence at night.NTSB CEN11LA076Accident · No injuriesLimited investigationFinal reportBeech 35-33 · Roanoke, TXA loss of engine power for undetermined reasons.NTSB CEN11LA077Accident · No injuriesLimited investigationFinal reportHalbrook Rans S-6S · St. Cloud, MNThe airplane kit manufacturer’s recommended use of an improper nut type for securing the door hinge.NTSB WPR11FA046Accident · 1 fatalField investigationFinal reportCessna 150J · Tucson, AZThe pilot's inability to maintain airplane control while on final approach due to undiagnosed cardiac disease, which caused a medical emergency and subsequent pilot incapacitation.NTSB ERA11CA057Accident · Serious injuriesData collectionFinal reportAeronca O58B · Livingston, NYThe pilot's improper fuel management, which resulted in a loss of engine power due to fuel exhaustion.NTSB ERA11LA050Accident · 1 fatalLimited investigationFinal reportNorth American/Schwamm AT-6F · Fitchburg, MAA total loss of engine power due to a cracked carburetor float and resulting carburetor malfunction.NTSB CEN11CA033Accident · Minor injuriesData collectionFinal reportMcClish B85C · New Baden, ILThe pilot's failure to maintain control of the airplane during landing.NTSB ERA11CA030Accident · Minor injuriesData collectionFinal reportCirrus SR20 · Sanford, FLThe student pilot's loss of directional control during a go-around maneuver following a bounced landing.NTSB ERA11LA025Accident · No injuriesLimited investigationFinal reportSchempp-Hirth Ventus B/16.6 · Warren, VTThe pilot's inadvertent deployment of the airbrake handle past the upper limit of its normal operating range, which resulted in binding of the controls.NTSB ANC11LA004Accident · No injuriesLimited investigationFinal reportBeech 1900C · Sitka, AKA lightning strike which resulted in substantial damage to the elevator.NTSB CEN11CA028Accident · Minor injuriesData collectionFinal reportWeddington Double Eagle · Temple, TXThe loss of engine power for undetermined reasons.NTSB CEN11CA030Accident · No injuriesData collectionFinal reportConrad Theodore J Thorp T-18 · Fredericksburg, TXThe malfunction of the throttle clamp, which resulted in the pilot's inability to control the engine's power setting.NTSB ERA11CA018Accident · Minor injuriesData collectionFinal reportLong EZ · Leesburg, FLThe pilot’s improper fuel management, which resulted in a loss of engine power due to fuel starvation.NTSB DCA11WA003Accident · 8 fatalForeign investigationLockheed L-100 · Kabul, AfghanistanOn October 12, 2010, about 1505 UTC, a Trans Afrique Airlines (under contract to National Air Cargo) Lockheed L-100, registration 5X-TUC, impacted terrain while maneuvering to land at Kabul International Airport (OAKB), Kabul Afghanistan. The two flight crew…NTSB WPR11LA012Accident · No injuriesLimited investigationFinal reportCessna 172 · Portland, ORThe pilot's inadequate preflight inspection and failure to ensure adequate fuel was onboard for the flight, which resulted in a total loss of engine power due to fuel exhaustion.NTSB CEN11LA014Accident · Serious injuriesLimited investigationFinal reportDrake Ronald A Acro Sport 1 · Fowlerville, MIThe pilot's loss of control during a go-around maneuver following a bounced landing. Contributing to the accident was the pilot's limited experience in the make and model airplane.NTSB ERA11CA045Accident · No injuriesData collectionFinal reportEvolution Revo · Gransonville, MDThe pilot's improper recovery from a bounced landing and the certificated flight instructor's inadequate remedial action, which resulted in an aerodynamic stall during a go-around.NTSB CEN11CA010Accident · Minor injuriesData collectionFinal reportMartin Curtis Zenair CH701 SP · Lonsdale, MNThe pilot's failure to maintain clearance from a power line while on approach to land.NTSB ERA11CA007Accident · Minor injuriesData collectionFinal reportAeronca 11AC · Taylorsville, KYThe pilot’s failure to maintain clearance from an unmarked power line during the final approach to land.NTSB ERA10LA506Accident · Serious injuriesLimited investigationFinal reportCirrus SR22 · Mathias, WVThe pilot's loss of control of the airplane during an instrument approach in turbulent weather conditions.NTSB CEN10LA572Accident · Serious injuriesLimited investigationFinal reportCessna 172RG · Tulsa, OKA shorted terminal lug on the landing gear hydraulic pump which resulted in a cabin fire. Contributing to the accident was the lack of clear installation procedures for the hydraulic pump.NTSB WPR10FA473Accident · 1 fatalField investigationFinal reportHawker Beechcraft F33 · Phoenix, AZA partial loss of engine power during approach for reasons that could not be determined because postaccident examination did not reveal any anomalies that would have precluded normal operation.NTSB ERA10CA505Accident · No injuriesData collectionFinal reportCessna 172S · Franconia, NHThe pilot’s delay in initiating a go-around, which resulted in an in-flight collision with a fence.NTSB WPR10CA469Accident · No injuriesData collectionFinal reportPiper PA-18-150 · White Sulphur Springs, MTThe pilot's failure to maintain control of the airplane during a go-around in turbulent wind conditions, which resulted in a collision with trees.NTSB CEN10FA557Accident · 2 fatalField investigationFinal reportPiper PA-44-180 · Woodruff, WIThe pilot's decision to attempt an instrument approach in turbulent night instrument meteorological conditions with a recently-identified deficiency with his instrument flight proficiency, which resulted in a loss of airplane control as a result of spatial…NTSB ERA10WA498Accident · Minor injuriesForeign investigationAero Commander 500 · Santo Domingo, Dominican RepublicNTSB ERA10TA493Accident · Minor injuriesFinal reportBell 412 · Brooklyn, NYThe fatigue fracture of the reduction gearbox output drive gear, which resulted in the loss of power output from the engines to the helicopter rotor blade system and a subsequent forced landing. The fracture of the output drive gear was caused by a fatigue…NTSB ANC10CA093Accident · Minor injuriesData collectionFinal reportCessna T310R · Nome, AKThe pilot's failure to maintain clearance from terrain during a special VFR approach, resulting in a collision with terrain.NTSB WPR10LA456Accident · Serious injuriesLimited investigationFinal reportSavage Savage-Cozy · Aurora, ORThe pilot’s failure to maintain control of the airplane following a loss of engine power in the traffic pattern; the cause of the loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not…NTSB ERA10FA471Accident · 1 fatalField investigationFinal reportCessna 182T · Helena, GAThe pilot’s continuance of the GPS approach below the minimum descent altitude while landing in instrument meteorological conditions.NTSB CEN10CA517Accident · Minor injuriesData collectionFinal reportBeech D35 · Guymon, OKThe loss of engine power for undetermined reasons.