Date: 201811
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Learjet 70
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Taxi
Reporter function: Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Object
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: Aircraft Aircraft Damaged; General Maintenance Action
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: During refueling; a grounding plug was dropped on the inboard portion of the flap causing a small dent. We were scheduled to depart that afternoon with 6 passengers. [Company] Maintenance were notified of the problem and pictures were sent. Over the phone; I was told that the dent did not meet any of the criteria that would require it to be repaired. As a result of this conversation; I did not find it necessary to enter a discrepancy in the aircraft log book as the dent appeared to be cosmetic in nature. We departed to ZZZ and then home to ZZZ1. The [next] morning; the airplane was scheduled to fly on a Part 135 flight. I again talked with Maintenance about the dent in the flap and they responded that they had looked at it in the morning and again found no cause for concern. We flew; then flew the planned flight for the day. [Several days later;] the aircraft was scheduled for routine maintenance at the manufacture. I asked them to take a look at the flap in hopes of repairing the cosmetic damage. It was determined from Lear Jet that the flap did in fact have structural damage and required a repair. At this time; I became aware that we had flown the aircraft over several legs in an unairworthy condition. I was asked by the Director of Operations to place a write up in the aircraft log book dated [the date of the incident] and to send it to Maintenance.The root cause of this was my failure to write up the damage on the ground. Contributing factors to my decision were that [Company] Maintenance had been advised by phone; text; and email; and did not believe that the damage was more than cosmetic.


Second narrative: While refueling prior to a passenger flight to be conducted under 14 CFR 135; the line service technician damaged the skin of the right flap when he dropped a grounding strap adapter onto the right flap panel after completing the refueling. I observed the refueling from start to finish and witnessed the dent and scratch in the right flap skin. I informed the Captain of the damage and the certificate holders. Director of Maintenance was contacted to determine airworthiness. The crew supplied photos and a verbal description of the damage. The DOM advised the crew verbally that the damage did not exceed the limits specified in the aircraft maintenance manual and would be verified upon return to operations base; so it was not necessary to write up the damage.The crew completed the 135 passenger flight and two repositioning flights under 14 CFR 91; the last of repositioning flight to an OEM factory service center five days after the damage occurred. The OEM service center determined the damage did in fact exceed the airworthiness limits. Upon learning this information; the certificate holder; Director of Operations; directed the crew to write up the damage retroactively; essentially forging the maintenance documents after the fact. The Captain and I refused.In hindsight; the Captain and I should have written up the damage as soon as it occurred and let the DOM sign it off as airworthy instead of accepting the verbal determination.


Synopsis: Learjet 70 flight crew reported minor damage discovered on the flap was later determined to be in an unairworthy condition.