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Cross Country - 50.9 or 49.0 hours?
 

Cross Country - 50.9 or 49.0 hours?

Chris VanHorn
2017-Jun-13

I am back from a long cross country round trip flight from Charlottetown, PE, Canada to Idaho Falls, ID, USA in a Piper Warrior II.  It was an excellent trip full of fun, sights and VFR interrupting weather.  In the end I logged 52.6 flight hours, 50.9 hours tach time and 49.0 hours time in service (air time).  

FromToHobbsTachTime in Service
CYYGKBGR2.62.32.3
KBGRKPBG1.91.811.6
KPBGKVGC1.81.681.6
KVGCN030.70.530.5
N03C654.64.624.4
C65C091.21.221.1
C09KLCG54.914.7
KLCGKAIA3.33.333.2
KAIAKEAN1.51.331.3
KEANKEMM2.82.752.6
KEMMKIDA1.51.41.3
KIDAKRKS2.32.212.1
KRKSKGGF3.33.283.2
KGGFKBIE2.82.712.6
KBIEI751.81.721.7
I75KHHG3.63.563.5
KHHGKFDY1.11.021.0
KFDYKBFD2.92.782.8
KBFDKAVP1.41.351.3
KAVPKBGR3.93.863.8
KBGRCYYG2.62.522.4
52.650.8949.0

So is the aircraft 50.9 or 49.0 hours closer to a 100-hour inspection?

The answer can be found in 14 CFR 91.409 (https://www.law.cornell.edu/cfr/text/14/91.409) which states:

(b) Except as provided in paragraph (c) of this section, no person may operate an aircraft carrying any person (other than a crewmember) for hire, and no person may give flight instruction for hire in an aircraft which that person provides, unless within the preceding 100 hours of time in service the aircraft has received an annual or 100-hour inspection and been approved for return to service in accordance with part 43 of this chapter or has received an inspection for the issuance of an airworthiness certificate in accordance with part 21 of this chapter. The 100-hour limitation may be exceeded by not more than 10 hours while en route to reach a place where the inspection can be done. The excess time used to reach a place where the inspection can be done must be included in computing the next 100 hours of time in service.

According to this regulation, 100 hour inspections are to be done every 100 hours of time in service (time in the air).  The correct answer is 49.0 hours closer to the next 100 hour inspection.  By using Time in Service instead of tachometer time, an aircraft owner can increase their flying hours between required 100-hour inspections.  This can result in additional revenue and aircraft availability.

Of course, you have to track time in service to be able to use it for maintenance planning.  Fortunately that is easy with the Canairy Cockpit Monitor.  It does it for you!