It appears that QantasLink (Cobham Aviation-operated) Boeing B717-200 VH-NXO broke down early on Saturday 28 July.
This means that only one B717-200 (being VH-NXD) was available to fly Central Queensland services out of Brisbane, and obviously, this saw several disruptions for passengers. As a result, few additional services popped into several Central Queensland airports over recent days, to transport the stranded passengers.
On Saturday 28 July, Qantas Boeing B737-400 VH-TJS was noted arriving into Mackay Airport from Brisbane as QF1348. This additional flight later departed back to Brisbane as QF1349.
Also, QantasLink Dash-8-Q400 VH-QOH (which wears Breast Cancer Awareness colours) operated as QLK2950/2951 Brisbane to Gladstone to Brisbane.
On Sunday 29 July, Alliance Airlines Fokker F-100 VH-FWH operated two return flights to Gladstone Airport from Brisbane - as shown in a Blog post below.
On Monday 30 July, QantasLink Dash-8's were used to fill the void - and interestingly, some of these flights were operated by aircraft either returning from or heading to other airports on fly-in fly-out (FIFO) duties.
From what I can see, Dash-8-Q400 VH-QOH operated as QLK2598/2599 Brisbane to Mackay to Brisbane.
Dash-8-Q300 VH-TQZ operated as QLK2586 flying from Brisbane to Rockhampton and then onto Moranbah, where it operated a FIFO charter back to Brisbane.
Meanwhile, Dash-8-Q400's VH-QON and VH-QOP both operated from Moranbah to Rockhampton to Brisbane, after first operating a FIFO charter flight from Brisbane direct to Moranbah.
On Wednesday 1 August, I noted that an additional B717-200 in the form on VH-NXM had ferried into Brisbane direct from Perth to fill the void while VH-NXO is being repaired.