Allegiant Air Flight 758
McDonnell Douglas DC-9-83 (MD-83) · Accident: wheels up landing
From Portsmouth International Airport at Pease (PSM) to Orlando Sanford International Airport (SFB)
Event
- NTSB case
- MIA07LA068
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
McDonnell Douglas DC-9-83 (MD-83)
- Aircraft type
- McDonnell Douglas DC-9
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N877GA
- Operator
- Allegiant Air
- Onboard fatalities
- Unknown
- Route
- From Portsmouth International Airport at Pease (PSM), Portsmouth, NHTo Orlando Sanford International Airport (SFB), Sanford, FL
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 121: Air Carrier
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Landing · emergency landing
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Wheels up landing
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Flightcrew › Checklist, not complied with
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The flight crew (FC) was in cruise flight when a master caution light illuminated indicating a loss of the right hydraulic system pressure and hydraulic fluid. The FC used the checklist to trouble shoot the system and attempted to manually extend the main and nose landing gear (NLG) using the alternate extension control lever. Both main gear extended and locked into place; however the NLG did not extend. The airplane was landed with the NLG in the retracted position. Initial inspection of the airplane revealed that a B-nut to the check valve on the rudder power hydraulic shut off valve, was separated from the valve resulting in a total loss of right hydraulic quantity and pressure. Examination of the hydraulic tube, including the B-nut and check valve, did not reveal any abnormalities. Examination of the cockpit revealed the landing gear handle was in the stowed position. A placard on the alternate landing gear extension lever stated, "Pull up forcibly Full Stroke." The airplane was placed on jacks and maintenance personnel successfully extended the nose landing gear. The alternate gear extension control system was also inspected and no defects were noted.
Probable cause
The flight crew's failure to complete the checklist and adhere to airplane placards. Contributing to the accident was a separation of a B-nut on the rudder power hydraulic shut off valve for undetermined reasons.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record MIA07LA068
- Event ID
- 20070409X00387
- Case number
- MIA07LA068
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: fff2304f224332fd01e353bc8d34e863972bcd450883b6734a94e7dc04346683; retrieved 2026-09-18T14:45:57.662Z.