Airworthiness Directive Lookup Free FAA AD search by N-number, make or model
Find the FAA airworthiness directives that may apply to an aircraft: 12,857 ADs from the Federal Register since 1995, through Oct 1, 2026, each with its applicability text and the official document. Free, no account.
N51FN is a 1976 Learjet 35A in the FAA registry (aircraft page). Matched on type certificate model 35A.
RESULTS
11 ADs in effect may apply to N51FN
- In effect11
- Recurring1
- Superseded or removed2
Informational only. These are FAA airworthiness directives whose published applicability names this make and model. Whether an AD applies to a particular aircraft depends on its serial number, installed engines, propellers, parts and modifications, and some ADs listed here will not apply. This list is not the official AD record and not a compliance determination: confirm applicability and compliance against the FAA’s Dynamic Regulatory System and the aircraft’s records with a certificated mechanic or inspector. Covers ADs published in the Federal Register since 1995, through Oct 1, 2026; older ADs, and engine, propeller and appliance ADs that do not name the aircraft, are not included.
Also show 2 superseded or removed N51FN’s registration record
- AD 2022-05-01 One-time
Learjet, Inc., Airplanes
This AD was prompted by a report indicating that a repair station performed a life extension program on spoiler assemblies that had reached or were close to reaching their life limit.
Applicability, as the AD words it
This AD applies to Learjet, Inc., Model 35, 35A (C-21A), 36, 36A, 55, 55B, 55C, and 60 airplanes, certificated in any category, with any spoiler assembly that meets any of the criteria identified in paragraph (c)(1) or (2) of this AD. (1) The spoiler assembly's life limit was extended by Restored Aircraft Sales and Service, LLC. (2) The maintenance records related to the life limit for the spoiler assembly are missing or incomplete.
- AD 2010-06-11 One-time Engine
Honeywell International Inc. TFE731 Series Turbofan Engines
We are issuing this AD to prevent an uncontained failure of a second stage LPCR disc and/or a third stage LPCR disc due to cracks in the bore, which could result in damage to the airplane.
Applicability, as the AD words it
This AD applies to Honeywell International Inc. TFE731-2, TFE731-2A, TFE731-2C, TFE731-3, TFE731-3A, TFE731-3AR, TFE731-3B, TFE731-3BR, TFE731-3C, TFE731-3CR, TFE731-3D, TFE731-3DR, TFE731-3R, TFE731-4, TFE731-4R, TFE731-5, TFE731-5AR, TFE731-5BR, and TFE731-5R series turbofan engines with certain second stage low-pressure compressor rotor (LPCR) discs, part number (P/N) 3072396-1 or 3075190-1, and/or certain third stage LPCR discs, P/N 3072397-1 or 3075192-1, installed. These engines are installed on, but not limited to, the airplanes listed in Table 1 of this AD. Table 1--Installed on Airplanes by Manufacturer Manufacturer Model Dassault-Aviation or Dassault Aviation. Falcon 10 (Falcon 100) and Mystere-Falcon 20, 50, 900 and MF900 series. Cessna Aircraft Company: Model 650, Citation III, VI, and VII. Gulfstream Aerospace LP: 1125 Westwind Astra. Israel Aircraft Industries: 1124 and 1124A (Westwind). Learjet Inc: 31, 31A, 35, 35A, 36, 36A, 55, 55B, 55C, and M31. Lockheed Martin Corporation (formerly 1329-23A, 1329-23D, 1329-23E, Lockheed-Georgia). and 1329-25. Raytheon Corporate Jets (formerly DH.125 Series 1A, 3A, and 3A/ British Aerospace and Hawker RA, HS.125 Series F3B and F3B/ Beechcraft Corporation). RA, BH.125 and DH.125 Series 400A, HS.125 Series 403B, F400B, and F403B, HS.125 Series 600A, BH.125 Series 600A, HS.125 Series F600B, 700A, and 700B, BAe.125 Series 800 and 1000, and Hawker 800 and 850XP series.
- AD 2007-17-17 One-time
Learjet Model 31, 31A, 35, 35A (C-21A), 36, 36A, 55, 55B, and 55C Airplanes, and Model 45 Airplanes
We are issuing this AD to prevent penetration of flammable liquids or fire through the engine firewall into the engine pylon, which could lead to fire inside the airplane.
Applicability, as the AD words it
This AD applies to Learjet Model 31, 31A, 35, 35A (C-21A), 36, 36A, 55, 55B, and 55C airplanes, and Model 45 airplanes; certificated in any category; as identified in the service information specified in Table 1 of this AD. Table 1.--Applicable Service Information Learjet airplane model Service Bulletin Revision level Date 31/31A: Bombardier Service 1: August 21, 2006. Bulletin 31-54-2. 45: Bombardier Service 2: August 15, 2003. Bulletin 45-54-3. 35/35A (C-21A) and 36/36A: Learjet Service Original: March 16, 2001. Bulletin 35/36-54-3. 55/55B/55C: Learjet Service Original: March 16, 2001. Bulletin 55-54-3.
- AD 2007-04-18 One-time
Learjet Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F, 28, 29, 31, 31A, 35, 35A (C-21A), 36, 36A, 55, 55B, and 55C Airplanes
We are issuing this AD to prevent this inadvertent operation, which could result in inadvertent fuel transfer by the left or right wing fuel system and subsequent over-limit fuel imbalance between the left and right wing fuel loads.
Applicability, as the AD words it
This AD applies to the Learjet models identified in the applicable Bombardier service bulletin listed in Table 1 of this AD. Table 1.--Applicability by Service Bulletin Bombardier service bulletin Revision level Date Learjet model(s) SB 23-28-6: Original: April 21, 1998: 23. SB 24/25-28-3: 2: February 21, 1998: 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, and 24F-A airplanes; and 25, 25A, 25B, 25C, 25D, and 25F airplanes. SB 28/29-28-4: 3: June 2, 1999: 28 and 29 airplanes. SB 31-28-7: 3: January 26, 2001: 31 and 31A airplanes. SB 35/36-28-11: 4: December 4, 2000: 35 and 35A (C-21A) airplanes; 36 and 36A airplanes. SB 55-28-13: 3: December 15, 2000: 55, 55B and 55C airplanes.
- AD 2005-13-36 One-time
Learjet Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F, 28, 29, 31, 31A, 35, 35A (C-21A), and 36 Airplanes
This AD was prompted by a report indicating that an aileron cable failed on one affected airplane when the cable underwent a tension check.
Applicability, as the AD words it
This AD applies to Learjet Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F, 28, 29, 31, 31A, 35, 35A (C-21A), and 36 airplanes; certificated in any category; as identified in the Bombardier alert service bulletins in Table 1 of this AD. Table 1.--Service Bulletins Bombardier alert service bulletin Date Model A23/24/25-27-17: December 23, 2002: 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, and 25F airplanes. A28/29-27-24: December 23, 2002: 28 and 29 airplanes. A31-27-25: December 23, 2002: 31 and 31A airplanes. A35/36-27-42: December 23, 2002: 35, 35A (C-21A), and 36 airplanes.
- AD 2004-03-08 Recurring
Learjet Model 31, 31A, 35, 35A (C-21A), 36, and 36A Airplanes
To prevent significant structural damage to the engine pylons, possible separation of the engines from the fuselage, and consequent reduced controllability of the airplane.
Applicability, as the AD words it
The following airplanes, certificated in any category, as applicable: Table 1.--Applicability As Listed in Bombardier Service Bulletin-- Model-- 31 and 31A Airplanes: 31-51-2, dated February 1, 2001; and 31- 51-3, Revision 1, dated August 2, 2001. 35, 35A (C-21A), 36 and 36A 35/36-51-3, dated February 1, 2001; and Airplanes. 35/36-51-4, Revision 1, dated August 2, 2001.
- AD 2001-07-11 One-time
Learjet Model 23, 24, 25, 28, 29, 31, 35, 36, and 55 Series Airplanes
Applicability, as the AD words it
All Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D- A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F, 28, 29, 31, 31A, 35, 35A (C-21A military), 36, 36A, 55, 55B, and 55C airplanes; certificated in any category.
- AD 2000-24-19 One-time
Learjet Model 35, 35A, 36, and 36A Series Airplanes
To prevent incapacitation of the flightcrew and consequent loss of control of the airplane due to delays in donning oxygen masks in response to the activation of the cabin altitude warning horn.
Applicability, as the AD words it
Model 35, 35A, 36, and 36A series airplanes, certificated in any category.
- AD 99-23-19 One-time
Learjet Model 31, 31A, 35, 35A, and 60 Airplanes
To prevent failure of the spoiler actuator, which could result in the spoiler panel floating and inducing an uncommanded roll of the airplane.
Applicability, as the AD words it
Model 31 and 31A airplanes, serial numbers 31- 033, 31-105, 31-114, 31-126, and 31-150 through 31-161 inclusive; Model 35 and 35A airplanes, serial numbers 35-065, 35-242, 35-300, 35-323, 35-447, 35-622, and 35-670; and Model 60 airplanes, serial numbers 60-029, 60-050, 60-120 through 60-139 inclusive; certificated in any category.
- AD 98-06-28 One-time
Learjet Model 31 and 35A Airplanes
To prevent electrical arcing and consequent fire hazard.
Applicability, as the AD words it
Model 31 airplanes having serial numbers 31-002 through 31-029 inclusive, and Model 35A airplanes having serial numbers 35-647 through 35-670 inclusive; certificated in any category.
- AD 96-19-13 One-time
Gates Learjet Model 35 and 36 Series Airplanes Modified by Raisbeck Supplemental Type Certificate (STC) SA766NW
To prevent deterioration of the airplane's lateral control characteristics as a result of aileron buffet or buzz.
Applicability, as the AD words it
Model 35, 35A, 36, and 36A series airplanes; certificated in any category; that have been modified in accordance with Raisbeck Group Supplemental Type Certificate (STC) SA766NW, and that do not have one of the airplane serial numbers listed in Table 1 of this AD. Table 1.--Serial Numbers* NOT affected by this AD 35-023 35A-092 35A-192 36-004 35-034 35A-093 35A-203 36-017 35-042 35A-095 35A-206 36-028 35-044 35A-118 35A-207 36A-029 35-047 35A-127 35A-209 36A-031 35A-068 35A-132 35A-228 36A-038 35A-073 35A-135 35A-231 36A-043 35A-075 35A-145 35A-244 36A-044 35A-076 35A-172 35A-245: 35A-086 35A-185 36-003: *Airplanes having the serial numbers listed in Table 1 are subject to similar requirements mandated by AD 85-16-04, amendment 39-5110.
Radar reads the logbooks and ties each AD to the entries that show how and when it was complied with, with recurring ADs due by date and hours.
QUESTIONS
AD lookup questions
Sources: FAA final rules under 14 CFR part 39, from the Federal Register; make and model from the FAA aircraft registry. The FAA’s Dynamic Regulatory System holds the official AD list.
What is an airworthiness directive (AD)?
An airworthiness directive is a legally enforceable rule the FAA issues under 14 CFR part 39 when it finds an unsafe condition in an aircraft, engine, propeller or appliance that is likely to exist in others of the same design. It says which products it applies to and what must be done, and by when: an inspection, a part replacement, a modification or a limitation. No one may operate a product to which an AD applies except in accordance with it.
How do I look up the ADs for my aircraft?
Type the N-number, or the make and model, into the box above. Radar finds the aircraft's make and model in the FAA registry and lists every AD published in the Federal Register whose applicability names it, newest first, with the AD's own applicability text and a link to the official document. The FAA's Dynamic Regulatory System (drs.faa.gov) holds the official list.
Does every AD in the results apply to my aircraft?
Not necessarily. An AD can be limited to serial number ranges, to aircraft with certain parts or modifications installed, or to a configuration. The results are ADs that may apply because they name the make and model. A certificated mechanic or inspector determines applicability against the aircraft's serial number and records, and records how each applicable AD was complied with.
What is the difference between a recurring and a one-time AD?
A one-time AD is complied with once, for example by replacing a part. A recurring (repetitive) AD requires an action again at an interval, such as an inspection every 100 hours or every 12 months, until a terminating action ends it. Radar marks an AD Recurring when its text requires repetitive actions; always read the AD for the intervals.
What does superseded mean?
When the FAA replaces an AD with a new one, the old AD is superseded: its requirements are carried into, or replaced by, the new AD. Results show the ADs in effect by default; superseded and removed ADs can be shown for the history.
Where does this data come from?
The Federal Register, where the FAA publishes every AD as a final rule. Radar reads each one from the Federal Register API (12,857 ADs since 1995) and refreshes the list every weekday. Make and model come from the FAA aircraft registry. ADs issued before 1995 are not in the Federal Register's online edition and are not included.
Are engine and propeller ADs included?
Only when their applicability names the aircraft. Most engine and propeller ADs name the engine or propeller model, so check those by the installed engine and propeller models. Appliance ADs that list the aircraft among those the appliance can be installed on are included and marked Appliance.
Know which ADs apply, and where each one was signed off.
Radar reads every logbook page, typed or handwritten, and builds one searchable record per tail: times, inspections, ADs and components, each tied to the page it came from.