REFERENCE
NADP-1 vs. NADP-2
Last Updated: 04 OCT 26
Comparison
| Feature | NADP-1 | NADP-2 |
|---|---|---|
| Purpose | Reduce noise close to the airport | Reduce noise farther from the airport |
| Acceleration in the note | 3,000 ft AFE | 1,000 ft AFE |
| Thrust reduction in the note | 1,000 ft AFE | Flaps selected to 1 or 5 |
| Flap retraction | Later, at acceleration height | Earlier, at acceleration height |
Choosing the profile
- Aerodata/ACARS does not tell the crew which noise profile applies.
- Verify the Airport Briefing pages, departure procedure and State Rules/Procedures; use the applicable airport/company procedure.
- NADP-1 delays acceleration to reduce noise close to the airport.
- NADP-2 accelerates earlier to reduce noise farther from the airport.
NADP-1 - Close-in profile
FMS:
- EO ACCEL HT: (Reference Performance sheet)
- ACCEL HT: 3000
- THR REDUCTION: 1000
What is happening?
With all engines operating, the 1000 entry sets thrust reduction at 1,000 ft above the airport. Thrust reduces to climb thrust, while acceleration is delayed. At 3,000 ft, the ACCEL HT entry marks the start of acceleration and flap retraction on schedule. The sequence is thrust reduction first, acceleration later.
EO ACCEL HT is separate: use the performance sheet for the engine-out acceleration height.
NADP-2 - Distant profile
FMS:
- EO ACCEL HT: (Reference Performance sheet)
- ACCEL HT: 1000
- THR REDUCTION: Flaps 1 or 5, depending on takeoff flap setting
What is happening?
With all engines operating, the 1000 entry marks the start of acceleration at 1,000 ft above the airport. As speed increases, retract flaps on schedule. In the setup shown, thrust reduction is tied to selecting Flaps 1 or 5, depending on the takeoff flap setting, rather than a fixed height. Acceleration and cleanup begin earlier than in NADP-1.
- NADP-2 is the preferred NADP when no restrictions or limitations apply. Typically used in the U.S.
"NADP-1.5" - Modified NADP-1
FMS:
- EO ACCEL HT: (Reference Performance sheet)
- ACCEL HT: 3000
- THR REDUCTION: 1500
What is happening?
With all engines operating, the 1500 entry sets thrust reduction at 1,500 ft above the airport. Acceleration remains delayed until 3,000 ft, when acceleration and flap retraction on schedule begin. Compared with the NADP-1 setup above, thrust reduction occurs 500 ft later; the acceleration height stays the same.
- This is the modified NADP-1 specified for EBBR in GOM FIB 25-11; it is an airport-specific example.
- TAKEOFF REF height entries are above origin airport elevation. Convert chart MSL altitudes before entering heights.
Source references
- K4 Profiles rev 8.0, PDF pp1-2: Noise Abatement Takeoff 1 / 2, close-in / distant profiles.
- FCTM section 3.10.7, PDF p127: Noise Abatement Takeoff; specific local airport procedures.
- GOM FIB 25-11, PDF p15 (printed p1): EBBR Noise Awareness; modified NADP-1. Effective 09 JUN 25; expiry indefinite in the local copy.