Let's talk Part 91 vs Part 135. These are two completely different worlds, like day and night.
Part 135 is highly structured and very similar to the 121 airline world, versus part 91 where things aren't as structured but you have less privileges. Let's dig into some of the biggest differences.
1) Ownership Operations
As an aircraft owner you absolutely cannot charter out your plane to people for the purpose of making money. If you buy a plane and want to make money off of this to use as an investment, then it should be used for the purpose of flight instruction. Can your friend fly it on a trip and pay you all expenses plus $600 so you have something to pocket? NO.
But what if they pay you in cash? I include this because as a CFI I get lots of questions about loopholes to regs. Paying cash isn't a loophole, it's still illegal. Whenever you encounter situations like this and think it may or may not be illegal, think of it like this: what if the aircraft crashes or has an incident and the FAA begins asking questions? will you be able to confidently explain everything about the flight to them and not have anything to worry about? If the answer is no, don't agree to the flight until you consult someone highly knowledgable in the regs and are 100% confident the situation you are faced with is legal.
-Remember that you can submit questions about regulations to the FAA and they will write back. It will take weeks to months but is a highly resourceful tool.
If you're looking into try to offset costs/generate revenue from your aircraft look into putting it on a 135 certificate! There are several different types of certifices you can apply for through this FAA 135 General Information Link. Also read Starting a 135 Operation by the NBAA to help guide you through this too.
2) Flight Operations
This list goes on and on for this subpart in the FAR/AIM but I'll highlight a few.
In Part 91.211 for an unpressurized aircraft, like a Piper Saratoga for example, pilots are not required to wear oxygen until passing 12,500 feet MSL. From 12,500 ft - 14,000 ft if there longer than 30 minutes than a mask is required, or any altitude past 14,000 a mask must be worn at all times.
With 14 CFR 135.89 the 30 minute duration period is brought down to 10,000 ft - 12,000 ft and now must be worn continuously past 12,000 ft rather than 14,000 ft. Therefore, the regulations are more strict in Part 135. But remember that 135 is given more priviliges including generating revenue, so it makes sense!
The requirements for a pressurized aircraft are more strict in 135 versus 91 as well.
3) IFR Takeoff, Approach & Landing Minimums
As an instrument pilot, these are VERY important to know. Your minimums are going to come from 14 CFR 91.175 and 14 CFR 135.225. These are linked because there is a lot to these regulations to know that need to be read from the primary source itself.
-What are standard takeoff minimums? The quick and easy answer for 135/121 operations is 1 statute mile visibility for one or two engines, or 1/2 mile for three or more engines.
-Are there takeoff minimums for part 91? A quick answer again for this....no. You can legally takeoff zero/zero unless you've been assigned and accepted a SID. But a smart pilot won't do this, so read further into your regs.
Note that when it comes to minimums, visibility is always prevailing. When I break out of a low ceiling, can I see a deer crossing the runway? Yes. Because I can see now! What if visibility is poor? Maybe not. You don't just "break out" of visibility like you break out of clouds.
Approach minimums: You may not begin an instrument approach unless the airport has an approved weather facility AND the latest weather is above minimums. A loophole to this is eligible on-demand can begin the approach without an approved weather facility if the alternate has one and have an approved altimeter setting. If you are shooting the approach and weather deteorates below minimums, you can only continue under certain circumstances such as if you're beyond the final approach fix. Otherwise, you have to go around.
These 3 bullet points are just 3 key differences between the Part 91 and Part 135 world. There's various other regulations that should be thoroughly looked over as well if you're transitioning from one operation to the other in order to not only stay legal but remain proficient.
Questions or comments? Confused by any of the regs in either of these parts that you'd like broken down? Write to us below! We always enjoy feedback from readers.
Cheers to 2021 and Happy New Year from everyone at Globalair.com!