Part 91 vs. Part 135 Staffing: What Changes When You Add Managed Aircraft

Putting aircraft on a Part 135 certificate changes who can fly them. The same pilot now needs federal duty and rest limits, recurring FAA checks, indoctrination on your certificate, and drug and alcohol testing. Onboarding runs weeks instead of days, so your usable crew pool shrinks the day the first managed aircraft arrives.

Your scheduler spends the first hour of the morning calling five pilots to fill one seat. Not five who are available. Five who are typed, current, indoctrinated on your certificate, and not sitting inside a rest period nobody can shorten.

The first aircraft onto the certificate never causes the problem. You cover the early trips out of the corporate side and it works fine. Somewhere around the fourth or fifth managed airplane it stops working, and it shows up on the schedule rather than in a compliance file.

More operations are running into this, because the certificate side is where the flying is. ARGUS put Part 135 charter activity up 4.5 percent year over year this past April and fractional flying up 13 percent, while Part 91 owner and corporate flying slipped 1.5 percent. A growing share of business aviation happens where the FAA, not your insurance underwriter, decides who is qualified to sit in the seat.

Take one pilot and one airplane. Fly it non-commercially under Part 91 on Monday and under Part 135 on Tuesday. Nothing about the pilot changed. Nine categories of federal obligation did.

Every one is a staffing constraint dressed as a regulation, and each narrows the pool of people who can legally fly your trip on short notice. Four cost the most.

Under Part 91, the FAA sets no flight time, duty time, or rest limits for your crew. Your limits come from your SOPs, your insurance, and whatever your chief pilot thinks is reasonable.

Under Part 135, 135.267 makes it arithmetic. Flight time is capped at 8 hours in any 24 consecutive hours for a single pilot and 10 for a two-pilot crew. Duty tops out at 14 hours, bracketed by 10 consecutive hours of rest. Cumulative ceilings run 500 hours a quarter and 1,400 a year. And the rest number moves when a trip runs long.

Sixty-one minutes of holding turns a 10-hour rest obligation into a 16-hour one. Your crew is now unavailable for a window that no longer fits tomorrow's schedule. That is not a paperwork problem. That is a second crew, sourced tonight. And rest means freedom from all obligation, so a crewmember sitting on call is not resting, a point NBAA has had to correct repeatedly.

Under 135.101, no person may carry passengers IFR under Part 135 without a second in command. The only exception is 135.105, an approved autopilot in lieu of an SIC, under an authorization written into your op specs.

So a single-pilot-certificated airplane that one captain flew IFR with passengers all year under Part 91 may need two qualified pilots per trip once it flies under the certificate. Not two names on a roster. Two people who have both been through your approved training program and passed the required checks. If you are building a bench for a managed fleet, this is the multiplier that breaks the spreadsheet.

Under Part 91, a captain in a turbojet or multi-pilot type needs a proficiency check under 61.58 once a year. Under Part 135, the same pilot picks up four recurring obligations: a written or oral test every 12 months under 135.293(a), a competency check in type every 12 months under 135.293(b), an instrument proficiency check every six months under 135.297 for IFR PICs, and a line check every 12 months under 135.299 over a real route segment. That last one applies to every Part 135 PIC, not only two-pilot operations, and it is the one operators most often get wrong.

The six-month IPC is what hurts scheduling. Every captain now has a cliff twice a year rather than once, and the cliffs do not line up. If nobody owns that calendar, you find out when a captain shows up for a trip he cannot legally fly.

Under 135.107, an aircraft with more than 19 passenger seats requires a flight attendant, and that person becomes a required crewmember: tested every 12 months under 135.295, given duty and rest limits under 135.273, and folded into your approved training program. A cabin attendant you used to book by preference is now a compliance object.

Then there is 14 CFR Part 120, which requires a DOT and FAA drug and alcohol testing program for anyone performing a safety-sensitive function for your certificate. That reaches wider than most people expect: dispatchers, operations control specialists, and anyone doing aircraft maintenance, temporary and intermittent people included, and explicitly people performing those functions by contract.

Read that last clause again. The contract A&P in your hangar and the temp scheduler covering vacation are inside the program, so if your staffing vendor is not running one, or is placing people as 1099 contractors, that exposure sits on your certificate. Our post on 1099 crew misclassification risk covers what the classification test looks at. A certificate is also what usually breaks a one-person scheduling desk, which is what ONeCALL Flight Dispatch covers.

The constraint stops being "can I find a pilot" and becomes "can I find a pilot who is already legal on my certificate this week."

Under Part 91, a qualified contract captain can often fly inside a few days: verify the certificate and medical, confirm time in type and currency, check that they clear your policy minimums, and go. Under Part 135 they cannot fly until they have completed basic indoctrination on your certificate, ground and flight training under your approved program, the 135.293 test and competency check, the 135.297 instrument check, and the 135.299 line check. Part 135 sets no programmed hour minimum for any of it, unlike Part 121, so the real number is whatever your approved program says.

Two details make that runway harder to shorten than people expect. You cannot credit training a pilot completed under another certificate holder's program, so ten years on the same airframe for the operator across the ramp does not transfer. And while a reduced curriculum is allowed for an experienced hire, indoctrination, emergency training, and CRM hours cannot be cut. Experience shortens the middle, not the front.

Which reorders how to think about a contract bench. A pilot you onboard in October is available in October. One you decide to onboard the night a captain calls in sick is not available at all. If you run a mixed fleet, qualify everyone to the Part 135 standard by default and let the Part 91 legs inherit it. Tracking two qualification states per person is how trips get canceled.