Study Tips5 min readApril 2026

The 20 Numbers Every Part 107 Pilot Must Memorize

The Part 107 test asks for specific numbers, and "about 400 feet" instead of exactly 400 fails the question. Here are the 20 numbers the FAA asks about most, grouped so the ones you will confuse sit side by side, with a memory trick for each.

The Part 107 test is a precision test. If you remember "about 400 feet" when the answer is exactly 400 feet AGL, the question is wrong. Same for "a few days" when the answer is 10 calendar days.

Good news: there are only 20 numbers you really need to lock in. They are grouped below so the ones you will confuse sit side by side, with a memory trick for each.

What altitudes do I need to know?

Number	What it means	Source
400 ft AGL	Maximum altitude for standard Part 107 operations	14 CFR § 107.51(a)
400 ft	Structure exception: may fly 400 ft above a structure's highest point	14 CFR § 107.51(a)
18,000 ft MSL	Floor of Class A airspace	FAA AIM Chapter 3
2,500 ft AGL	Typical ceiling of Class D airspace	FAA AIM Chapter 3
1,200 ft AGL	Where Class E typically begins (away from airports)	FAA AIM Chapter 3

Speed, visibility, and cloud clearance

Number	What it means	Source
87 knots (100 mph)	Maximum groundspeed	14 CFR § 107.51(b)
3 statute miles	Minimum flight visibility	14 CFR § 107.51(c)
500 ft below clouds	Minimum vertical cloud clearance	14 CFR § 107.51(d)
2,000 ft horizontal	Minimum horizontal cloud clearance	14 CFR § 107.51(d)

The speed limit is the classic trap. The legal limit is 100 mph, which converts to 87 knots. The FAA lists both.

Test-takers see "100" and assume 100 knots. But 100 knots is 115 mph, well above the legal limit. 87 is the number to remember.

For cloud clearance, remember it as a pair: 500 down, 2,000 sideways. Both numbers appear together on nearly every weather minimums question.

Time limits and currency

Number	What it means	Source
10 calendar days	Window to report an accident to the FAA	14 CFR § 107.9
24 calendar months	Recurrent training/testing cycle	14 CFR § 107.65
8 hours	"Bottle to throttle": no alcohol within 8 hours of acting as PIC	14 CFR § 107.27
0.04%	Maximum blood alcohol concentration while acting as PIC	14 CFR § 107.27
30 minutes	Civil twilight window before sunrise / after sunset for night ops	14 CFR § 107.29
30 minutes	Time it takes for eyes to fully adapt to darkness	FAA Study Guide

Weight and registration

Number	What it means	Source
55 pounds	Maximum takeoff weight for a "small UAS" under Part 107	14 CFR § 107.3
0.55 pounds (250g)	Registration threshold under Part 48 (must register if at or above this)	14 CFR § 48.15
0.55 pounds or less	Maximum weight for Category 1 operations over people (no waiver)	14 CFR § 107.120
16 years old	Minimum age for a Remote Pilot Certificate	14 CFR § 107.61(a)
13 years old	Minimum age to register a drone under Part 48	14 CFR § 48.25
$500	Property damage threshold that triggers mandatory accident reporting	14 CFR § 107.9
70%	Minimum passing score on the knowledge test	FAA Testing
60 questions	Total questions on the UAG knowledge test	FAA Testing

How do I actually remember all this?

Group them by regulation. The operating limits (altitude, speed, visibility, cloud clearance) all come from 14 CFR § 107.51. When a question hits any of those topics, it traces back to one place.

The time numbers tell a story. The accident report window is short (10 days) because the FAA wants timely data. The recurrent cycle is long (24 months) because the material does not change quickly.

The alcohol window (8 hours) matches the general aviation "bottle to throttle" standard. It is the same number new pilots have been memorizing for decades.

The 0.55 lb number does double duty. It triggers drone registration. It also enables Category 1 operations over people.

The 55 lb number is the Part 107 ceiling. Same first digits as 0.55, but very different test contexts. Watch for them appearing close together in answer choices, where a quick read can lead you to the wrong one.

Ready to test your knowledge?

Practice with real FAA style questions and get detailed explanations for every answer.

Frequently asked questions

What is the maximum altitude for a Part 107 drone flight?

The maximum altitude is 400 feet AGL (above ground level). The exception is the structure exception: when within 400 feet of a structure, you may fly up to 400 feet above the structure's highest point. A 300-foot tower legally lets you fly at 700 feet AGL.

What is the maximum speed for a Part 107 drone?

The legal limit is 100 mph (87 knots) groundspeed. The FAA always lists both units. Watch out for "100 knots" as a distractor answer; 100 knots is 115 mph, well above the legal limit.

How long do I have to report a drone accident to the FAA?

10 calendar days, counted from the day of the accident. Reporting is required when there is serious injury or property damage over $500 (excluding the drone itself). The window is calendar days, not business days; weekends and holidays count. Submit through FAA DroneZone.

What is the Part 107 weight limit?

The Part 107 ceiling is 55 pounds total takeoff weight, including the drone, payload, and anything attached. Drones weighing 0.55 pounds (250g) or more must be registered. Drones under 0.55 pounds are exempt from registration but still subject to other Part 107 rules during commercial flights.

How long is the Part 107 certificate valid?

The Remote Pilot Certificate itself does not expire. To keep your privileges active, you must complete recurrent training every 24 calendar months. If you let currency lapse, the certificate is still valid, but you cannot legally fly commercially until you complete recurrent training again.