I'm not a pilot but it looks like the airport has a airplane size restriction unless airport manager approves.
The Saab 2000 is a 58 passenger. I certain there is a reasonable explanation.

UNALASKA (DUT)(PADU) 1 N UTC–9(–8DT) N53º53.94´ W166º32.70´
23 B TPA—2101(2078) ARFF Index—See Remarks NOTAM FILE DUT
RWY 13–31: H4500X100 (ASPH–GRVD) S–60, 2D–210
PCN 86 F/B/X/T MIRL
RWY 13: REIL. VASI(V4L)—GA 3.0º TCH 38´. Thld dsplcd 300´. Boat.
RWY 31: REIL. VASI(V4R)—GA 3.0º TCH 32´. Thld dsplcd 300´. Boat.
Rgt tfc.
RUNWAY DECLARED DISTANCE INFORMATION
RWY 13: TORA–4500 TODA–4500 ASDA–4200 LDA–3900
RWY 31: TORA–4337 TODA–4500 ASDA–4200 LDA–3900
SERVICE: FUEL JET A LGT For MIRL Rwy 13–31, REIL Rwys 13 and
31; stop lgt for vehicle tfc crossing Rwy 31 thld; key 122.6 – 7 times
for on, 3 times for stop lgt and REIL off. VASI Rwy 13 and Rwy 31 opr
continuously. VASI Rwy 31 usable distance is 1.4 miles due to
mountain. VASI right side of rwy skewed 5º south of rwy heading.

AIRPORT REMARKS: Attended 1700–0130Z‡. Class I, ARFF Index A.
CLOSED to air carrier ops with more than 30 pax seats exc PPR in
writing to arpt mgr P.O. Box 920525, Dutch Harbor, AK 99692.

ARFF
eqpt staffed only during periods of large air carrier ops. Arpt maint duty
hrs 1700–0130Z‡ Mon thru Sun. Arpt hazard reporting only
performed during maintenance duty hrs and for air carrier ops over 30
pax seat acft. Snow removal and deicing of rwy, twy, and ramps only
performed during maintenance duty hrs. Tfc pattern around mountain. Tran acft must park on Ramp B. Be alert: vessel
tfc within 1,500´ from Rwy 13. Be Alert: Vessel fueling dock within 1,300´ from Rwy 31. Arpt area subject to moderate
to extreme concentrations of birds. Do not perform locked wheel turns on Rwy 13–31. Personnel and eqpt may be working
on the rwy at any time. Jet blast area AER 31 clsd to taxiing acft exc when road vehicle and pedestrian tfc is ctld by oprs
representative. Clockwise turn requested. For seaplane gate opr key 122.8, 7 times to open, 3 times to close, gate closes
automatically after 5 minutes. See Section "C" notices for gate ctl procedure.
AIRPORT MANAGER: 907-581-1786
WEATHER DATA SOURCES: AWOS–3P 125.8 (907) 581–2803. (WX CAM)
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