# AD 71-24-04: Flexible Hoses In Engine Compartment - Type: Airworthiness directive - Status: Current - Products: Cessna 177, 206, 210D, 210E, 210F, 210G, 210H, 336, 337, 337A, 337B, 337C and 19 more - Effective: November 23, 1971 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-1340 - Registered aircraft: 1,525 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9CBDF0C33F477B3786256A34006306BF.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/71-24-04 ## The airworthiness directive 71-24-04 CESSNA: Amdt. 39-1340. Applies to following airplanes: MODELS SERIAL NUMBERS AFFECTED 177 661, 17700001 and 17700003 thru 17701164 206 206-0001 thru 206-0275 U206 U206-0276 thru U206-0437 P206 P206-0002 thru P206-0160 U206A U206-0438 thru U206-0656 P206A P206-0161 thru P206-0306 TU206A U206-0487 thru U206-0656 P206B P206-0307 thru P206-0419 TU206B U206-0657 thru U206-0914 TP206A P206-191 thru P206-0306 TP206B P206-0307 thru P206-0419 U206B U206-0657 thru U206-0914 P206C, TP206C P206-0420 thru P206-0519 U206C, TU206C U206-0915 thru U206-1234 210D 21058221 thru 21058510 210E 21058511 thru 21058715 T210F T210-0001 thru T210-0197 210F 21058716 thru 21058818 T210G T210-0198 thru T210-0307 210G 21058819 thru 21058936 T210H T210-0307 thru T210-0392 210H 21058937 thru 21059062 336 633, 636, 336-001 thru 336-0195 337 337-0002 thru 337-0239 337A 337-0240 thru 337-0525 (except 337-0306 and 337-0470) 337B 337-0001, 337-0470, 337-0526 thru 337-0755 T337B 337-0001, 337-0526 thru 337-0755 (except 337-0569) 337C, T337C 337-0756 thru 337-0978 Compliance: Required as indicated, unless already accomplished. To detect leakage of flammable fluids from flexible hose assemblies in the engine compartment within 100 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 100 hours' time in service, accomplish the following: A. Visually, or by any other method approved by FAA, inspect fuel lines as follows: 1. Pressurize the fuel lines with boost pump operating in high position. When accomplishing this test, the mixture control should be in the idle cutoff position. 2. With fuel lines pressurized, examine all flexible hose exteriors in the engine compartment for evidence of fuel stains, wetness, or leakage. 3. After pressure testing fuel hoses, allow sufficient time for excess fuel to drain overboard from the engine manifold before attempting an engine start. B. Visually, or by any other method approved by the FAA, inspect oil lines for evidence of wetness or leakage. C. If, as a result of the inspections required by Paragraphs A or B, fuel and/or oil stain, wetness or leaking is found, replace with a serviceable hose assembly. D. Inspections required by Paragraphs A and B will no longer be required when hose assemblies are replaced with assemblies having a Cessna dated metal tag attached. TSO-C53a Type C approved hose assemblies are also acceptable for this replacement. (See Note 1) NOTE 1: This does not preclude continued inspections of this area as required by FAR 91. NOTE: Cessna Service Letter SE71-7, Supplement No. 1 dated November 3, 1971, covers this subject. The above airplanes use Aeroquip 601 series or Stratoflex 156 series hose assemblies available under Cessna P/N S1236-x-xxxx. The hose assemblies are identified by a steel braided exterior. This amendment becomes effective November 23, 1971. ## Affected data sheets (5) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A4CE](https://openairdocs.org/tcds/A4CE): Textron Aviation Inc.; names 15 of 29 models: TP206B, TP206C, TU206A, U206, P206C, TP206A, 206, P206A… - [TCDS 3A21](https://openairdocs.org/tcds/3A21): Textron Aviation Inc.; names 8 of 28 models: 210D, 210H, 210E, T210F, T210G, 210G, T210H, 210F - [TCDS A6CE](https://openairdocs.org/tcds/A6CE): Textron Aviation Inc.; names 6 of 19 models: 337, T337B, 337C, 337A, T337C, 337B - [TCDS A13CE](https://openairdocs.org/tcds/A13CE): Textron Aviation Inc.; names 1 of 3 models: 177 - [TCDS A2CE](https://openairdocs.org/tcds/A2CE): Textron Aviation Inc.; names 1 of 1 models: 336 ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 1,525 (1,525 by airframe model, 0 by engine model) - Makers: Cessna 1,524, Cessna Conroy 1 Models with the most aircraft: - [Cessna 177](https://openairdocs.org/model/cessna-177): 446 aircraft (airframe model) - [Cessna 210D](https://openairdocs.org/model/cessna-210d): 123 aircraft (airframe model) - [Cessna 210E](https://openairdocs.org/model/cessna-210e): 74 aircraft (airframe model) - [Cessna T210F](https://openairdocs.org/model/cessna-t210f): 65 aircraft (airframe model) - [Cessna 206](https://openairdocs.org/model/cessna-206): 55 aircraft (airframe model) - [Cessna 337A](https://openairdocs.org/model/cessna-337a): 55 aircraft (airframe model) - [Cessna P206](https://openairdocs.org/model/cessna-p206): 53 aircraft (airframe model) - [Cessna U206](https://openairdocs.org/model/cessna-u206): 52 aircraft (airframe model) - [Cessna 337](https://openairdocs.org/model/cessna-337): 50 aircraft (airframe model) - [Cessna U206C](https://openairdocs.org/model/cessna-u206c): 47 aircraft (airframe model) - [Cessna U206B](https://openairdocs.org/model/cessna-u206b): 43 aircraft (airframe model) - [Cessna 337B](https://openairdocs.org/model/cessna-337b): 40 aircraft (airframe model) - [Cessna 210G](https://openairdocs.org/model/cessna-210g): 39 aircraft (airframe model) - [Cessna 210H](https://openairdocs.org/model/cessna-210h): 38 aircraft (airframe model) - [Cessna 336](https://openairdocs.org/model/cessna-336): 35 aircraft (airframe model) - [Cessna 210F](https://openairdocs.org/model/cessna-210f): 34 aircraft (airframe model) - [Cessna 337C](https://openairdocs.org/model/cessna-337c): 33 aircraft (airframe model) - [Cessna P206A](https://openairdocs.org/model/cessna-p206a): 31 aircraft (airframe model) - [Cessna T210H](https://openairdocs.org/model/cessna-t210h): 26 aircraft (airframe model) - [Cessna T210G](https://openairdocs.org/model/cessna-t210g): 25 aircraft (airframe model) All 32 models: https://openairdocs.org/ad/71-24-04/models.md Every aircraft: https://openairdocs.org/ad/71-24-04/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.