Firstly Andrew Tyrie wasn't happy with the government over what assurances Nissan had been given on Brexit, writing to the head of the National Audit Office for more detail.
And now, the chairman of the Treasury Committee has called on the government to be more forthcoming on Heathrow expansion too.
The Conservative politician has written to Chancellor Philip Hammond about the economic case for expansion, and stressed that: "Parliament is being asked to vote on the biggest infrastructure project in a generation. It is crucial that it has all the tools at its disposal."
In his latest letter to the Chancellor, dated 8 December, Tyrie said it was important the process "is transparent and accountable".
Tyrie said: "The Chancellor should publish the cost-benefit analysis over shorter appraisal periods, and under the different 'demand scenarios' proposed by the Commission. This is not a new request. The Treasury Committee has been asking for this information since November 2015.
The government’s revised economic case, published alongside the announcement of its decision to expand Heathrow on 25 October, also raises a new question.
Of the four investment measures used to evaluate the proposals, only the seldom-used Net Public Value measure presents a clear case for a third runway at Heathrow.
The Chancellor needs to explain how much weight was placed on this measure when making the decision to expand the airport, and why.
The Net Public Value considers only those impacts that are directly felt by the public, so excludes the direct impacts on both the airport and the airlines that use it.
When the government published its own assessment of the Airport Commission's economic case in October, Tyrie noted it had answered some of his previous questions, but some remain unanswered.
He has previously accused Hammond's predecessor George Osborne of "obfuscation and delay", after repeatedly demanding more information on airport expansion.
It comes after Transport for London (TfL) criticised the government for not sharing information over matters such as air quality.
A DfT spokesman said: “We have regular meetings with TfL on airport surface access issues and these will continue in the future.
“We recognise TfL will have an important role in making surface access to the airport work.”