A survey drone is booked to map a conservancy boundary between seven and half past nine in the morning, never higher than 400 feet. A helicopter operator has low-level work over the same ground between eight and nine. Both crews have done their homework. Neither knows the other is coming.
That is the problem KASS, the Kenya Airspace Safety System, is built to solve. It comes from the same team as AngaBrief, and this 75-second video shows how it works.
The Short Version
- KASS is a companion to AngaBrief. AngaBrief helps pilots and instructors check PAVE and IMSAFE risk before the flight. KASS adds the other half of the picture: who else will be in the air.
- Operators declare their flights in advance: area, height band and time window. KASS shows every declared flight on one map.
- When two declared flights overlap in area, height and time, KASS alerts both pilots by SMS and WhatsApp, early enough for them to coordinate.
- Drone operators can check a survey area against every Kenyan airstrip before take-off. 345 aerodromes and bush strips are already loaded.
- KASS is advisory only. It is not air traffic control and it does not authorise anything; the Kenya Civil Aviation Authority does that.
- KASS is still in testing and not yet open to operators. This article explains what it is meant to do, so schools and operators can tell us whether it would help them.
Same airspace, nobody sees both
The low airspace over Kenya's national parks, conservancies and bush strips used to belong almost entirely to light aircraft on safari and charter runs. It is now shared with helicopters doing game counts, filming and anti-poaching patrols, and with a fast-growing number of drones flying mapping, survey and inspection jobs.
Each of those groups plans carefully within its own world. A charter pilot checks NOTAMs and files a flight plan. A drone operator works within the KCAA drone regulations and the limits of their authorisation. A helicopter crew briefs its own low-level task. What none of them has is a single place that shows all of those plans side by side, in the same time window, over the same patch of ground.
The usual last line of defence is see and avoid. It works poorly here. A small drone is very hard to see from a cockpit, a helicopter working low against a tree line blends into the background, and a drone pilot looking at a screen may not hear an aircraft until it is close. A warning that arrives an hour before the flight is worth far more than one that arrives as a shape in the windscreen.
What KASS does
One map of declared flights. Operators declare a flight with its area, its height band above ground and its time window. KASS draws every declared flight on the same map, so a drone survey, a helicopter task and a light aircraft movement in the same area appear together.
Overlap checks in three dimensions plus time. Two flights only conflict if they share area, height and time at once. A drone at 0 to 400 feet and a helicopter at 300 to 1,000 feet over the same ground overlap in height between 300 and 400 feet; if their windows also overlap, KASS flags it. A flight above the drone's ceiling, or an hour later, does not raise a warning.
Alerts to both pilots. When KASS finds an overlap, it sends the warning to both parties by SMS and WhatsApp, the channels Kenyan crews already carry. The point is not to cancel anyone's flight but to get the two people concerned talking early enough to agree a height, a time or a boundary.
Airstrip check for drone operators. Before take-off, a drone operator can check the survey area against every Kenyan aerodrome and bush strip KASS knows about, 345 of them at launch, and see at a glance whether the job sits close to a strip that light aircraft use.
A worked example
The demonstration in the video uses exactly the case from the start of this article.
- Declared drone survey: 07:00 to 09:30 local, 0 to 400 feet above ground.
- Declared helicopter low-level work: 08:00 to 09:00 local, over the same area.
- KASS draws both on the map, finds that the areas overlap, that the height bands overlap at the top of the drone's range, and that the time windows overlap for the whole hour from 08:00 to 09:00.
- Both pilots receive the same warning, marked advisory and not air traffic control, with the overlapping height band and the hour in question.
The fix is then ordinary airmanship: the drone operator pauses or caps the survey below the helicopter's floor for that hour, or the two crews split the area. KASS does not decide; it makes sure the conversation happens before anyone is airborne.
Where KASS fits with AngaBrief
AngaBrief and KASS cover two different moments.
- Before the flight, AngaBrief: the PAVE and IMSAFE risk assessment, the instructor's sign-off, and a KCAA-compliant audit log of every brief.
- In the air, KASS: who else is flying and where, the restriction and aerodrome information that matters for the area, and alerts by SMS and WhatsApp.
Put simply: AngaBrief prepares the pilot, and KASS shows who else is flying. A flight school using AngaBrief would see KASS information as part of the same picture a student checks before a cross-country into bush strip country.
What KASS is not
It is worth being clear, because safety tools that overclaim do harm.
- Not air traffic control. KASS gives no clearances and no separation. Pilots remain responsible for collision avoidance, exactly as before.
- Not an authorisation. Declaring a flight on KASS does not replace any KCAA approval, drone permission, flight plan or NOTAM. Those rules apply in full.
- Only as complete as its declarations. KASS can only warn about flights that have been declared. An undeclared drone or aircraft is invisible to it, which is why see and avoid, radio calls and bush strip discipline still matter.
Where it stands, and how to get involved
KASS is being tested by the AngaBrief team and is not yet open to operators. The aerodrome and bush strip data is in place and the overlap checks and alerts are working in the demonstration. What it needs next is the people who fly low over Kenya every day, drone operators, helicopter crews, safari and charter pilots, flight schools and park and conservancy managers, telling us how they would want to declare flights and receive warnings.
If you fly or manage flying in Kenya's low airspace and want early access to KASS, write to hello@angabrief.com with what you fly and where. Flight schools already using AngaBrief will hear first.
KASS is an advisory safety tool. It does not replace KCAA regulations, approvals or air traffic services.