AD 77-13-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Textron Aviation Inc. | BH.125 Series 400A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | BH.125 Series 600A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 1A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 1A-522 | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 1A/R-522 | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 1A/S-522 | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 3A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 3A/R | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 3A/RA | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 400A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 Airplanes |
Unsafe Condition
Failure of the knife edges of the brake control valve, P/N AC. 61520, which could result in possible complete loss of braking on one side of the airplane with no advance warning to the flight crew.
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Required Actions
Replace the knife edges with new parts P/Ns ACO. 34629, ACO. 34630, and ACO. 36133, following Service Bulletin 32-166 or FAA-approved equivalent. Alternatively, replace the brake control valve P/N AC. 61520 with a valve incorporating the specified knife edges, following the same service bulletin.
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Compliance Time
Prior to the accumulation of specified landings as follows: (1) 4,500 landings for those with <4,300 landings on effective date; (2) additional 200 landings for those with 4,300-5,899 landings; (3) 6,100 landings or additional 100 landings (later) for those with ≥5,900 landings; (4) 100 landings post-effective date if no records exist. Thereafter, comply every 4,500 landings.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
HAWKER SIDDELEY AVIATION, LTD Model DH/BH-125 airplanes, all series, certificated in all categories.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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