Investigation brief · generated 2026-10-09 · source: NTSB public docket and accident database
EMBRAER ERJ170 200LR — San Antonio, TX, USA, 2016-12-04
NTSB number
ENG17IA005
Operator
SKYWEST AIRLINES INC
Registration
N161SY
Highest injury
Minor injury
Regulation
Part 121
Damage
Minor
Cohort
Part 121 airline
Recorder data
Tier 1 — decoded recorder tables
Every sentence below is taken directly from NTSB records — the accident database, the docket's recorder reports and the Board's findings — with its source noted. Nothing is paraphrased or inferred.
NTSB summary
Based on the material laboratory examinations, the area around the failure point contained higher than allowable levels of retained austenite. The presence of too much retained austenite subsequently resulted in the formation of intergranular cracking. The intergranular cracking resulted in the formation of progressive cracking, which caused the separation and subsequent failure of the downlock spring. After the failure, the spring became lodged in the nose landing gear yoke, which prevented the nose gear from achieving a down and locked position. Without the NLG being fully down and locked, as the weight of the aircraft during landing was transferred to the nose and main landing gear, the NLG subsequently retracted back into the nose gear wheel.
A failure of the nose landing gear down lock spring which precluded normal downlock operation of the nose landing gear. The spring failure was due to the presence of too much retained austenite which led to the formation of progressive cracking and subsequent failure of the spring.
Computed from the docket's tabular attachment; times as recorded (local or SRN as published).
Sequence of events (FDR factual report)
Time
Event
Page
18:16
Flight departed and climbed to cruise altitude of 36,000 ft
3
19:06
Aircraft began to descend
3
19:30:08
Landing gear commanded down with landing gear lever, aircraft descending through 3,677 ft; left, right, and nose landing gear status transitioned from Up and Locked to In Transit
3
19:30:20 (approx, 12 sec after transition)
Left and right landing gear status became Down and Locked; nose gear status remained In Transit
3
19:30:29
Master Warning annunciated with associated Gear Lever Disagree message (7 seconds after main gear became Down and Locked)
3
~19:31:00
Aircraft stopped its descent at about 3,650 ft
3
19:31:34
Gear handle moved to the up position; both main and nose gear transitioned to Up and Locked; Gear Lever Disagree message cleared
3
~19:36 (about 5 minutes after 19:31:34)
Gear handle moved to down position again, with same result as first attempt (nose gear remained In Transit)
3
19:40:48
Gear handle moved back to up position; aircraft began to climb
3
20:02
Aircraft climbed to 33,000 ft then began a second descent
3
20:18:40
Gear handle moved to down position with aircraft descending through 10,200 ft; all gear status became In Transit, followed by left and right gear becoming Down and Locked; nose gear status remained In Transit
3
20:19:12
Gear retracted
3
20:19:34
Gear commanded down again; left and right gear transitioned to Down and Locked, nose gear remained In Transit
3
20:29
Aircraft descended to 500 feet AGL for one minute
3
20:29-20:41 (approx, climb then circle for ~12 minutes)
Aircraft climbed to 4,000 ft where it circled one time
3
20:49
Aircraft began its final descent
3
prior to 20:53:28
Airspeed stable at 130-132 knots during approach
3
20:53:28
Aircraft touched down on main gear at KSAT runway 4 with airspeed 113 knots and ground speed 95 knots
3
20:53:28 to 20:53:38 (approx 10 sec)
Pitch decreased slowly to a value consistent with the nose gear resting on the ground
3
20:53:41
Nose gear began to retract at a ground speed of 52 knots with no change in the recorded gear handle position
4
~20:53:51 (about 10 seconds later)
Aircraft slowed to a stop; final resting pitch of the aircraft was -5.98 degrees
4
20:53:54
Engines were shut down and recording stopped
4
Extracted by claude-sonnet-5; 9 of 22 stated events verified against the raw recorder data.